XML-XSH2/lib/XML/XSH2/Help.pm
# This file was automatically generated from src/xsh_grammar.xml on
# Sun Jun 12 16:34:31 2022
package XML::XSH2::Help;
use strict;
use vars qw($HELP %HELP $Apropos);
$HELP=<<'END';
Welcome to XSH help
-------------------
In this help:
[topic] is a cross reference that can be followed using 'help topic'
XSH2 acts as a command interpreter. Individual commands must be separated
with a semicolon. In the interactive shell, backslash may be used at the
end of a line to indicate that a command continues on the next line.
Output redirection can be used to pipe output of some XSH [command] to
some external program, or to capture the output to a variable. See
[Redirection] for more info.
XSH2 command [help] provides a complete reference, instantly from the
command-line:
'help command' gives a list of all XSH2 [commands].
'help type' gives a list of all argument types.
'help topic' followed by documentation chapter gives more information on
a given topic.
'help toc' displays the table of contents.
Within the interactive shell, press <TAB> for auto-completion.
END
$HELP{'toc'}=[<<'END'];
Help items:
-----------
toc - this page
XSH Language Topics:
Argtypes - Argument Types
Configuration - Global settings
Documents - Files/Documents
Flow - Flow control
Information - Retrieving more information
Manipulation - Tree modification
Namespaces - Namespaces in XML and XPath
Navigation - Tree navigation
Perl_shell - Interacting with Perl and Shell
Prompt - Prompt in the interactive shell
Redirection - Command output redirection
Variables - Variables
xsh2delta - Changes since XSH 1.x
XSH Commands:
apropos, assign, backups, call, canonical, catalog, cd,
change-ns-prefix, change-ns-uri, clone, close, copy, count, create,
debug, declare-ns, def, defs, do, doc-info, documents, dtd, edit,
edit-string, empty-tags, enc, encoding, eval, exec, exit, fold,
foreach, get, hash, help, if, ifinclude, include, indent, index,
insert, iterate, keep-blanks, last, lcd, lineno, load-ext-dtd, local,
locate, ls, map, move, my, namespaces, next, nobackups, nodebug,
normalize, open, parser-completes-attributes, parser-expands-entities,
parser-expands-xinclude, pedantic-parser, perl, prev, print,
process-xinclude, pwd, query-encoding, quiet, recovering, redo,
register-function, register-namespace, register-xhtml-namespace,
register-xsh-namespace, remove, rename, return, run-mode, save, set,
set-dtd, set-enc, set-ns, set-standalone, set_filename, settings,
skip-dtd, sort, stream, strip-whitespace, switch-to-new-documents,
test-mode, throw, try, undef, unfold, unless, unregister-function,
unregister-namespace, validate, validation, variables, verbose,
version, while, wrap, wrap-span, xcopy, xinsert, xmove,
xpath-axis-completion, xpath-completion, xpath-extensions, xslt,
xupdate
XSH Argument Types:
$variable, block, command, document, encoding, expression, filename,
location, node-type, nodename, perl-code, subroutine, xpath
XPath Extension Functions:
xsh:base-uri, xsh:context, xsh:current, xsh:doc, xsh:document,
xsh:document-uri, xsh:documents, xsh:evaluate, xsh:filename, xsh:grep,
xsh:id2, xsh:if, xsh:join, xsh:lc, xsh:lcfirst, xsh:lineno, xsh:lookup,
xsh:map, xsh:match, xsh:matches, xsh:max, xsh:min, xsh:new-attribute,
xsh:new-cdata, xsh:new-chunk, xsh:new-comment, xsh:new-element,
xsh:new-element-ns, xsh:new-pi, xsh:new-text, xsh:parse, xsh:path,
xsh:resolve-uri, xsh:reverse, xsh:same, xsh:serialize, xsh:span,
xsh:split, xsh:sprintf, xsh:strmax, xsh:strmin, xsh:subst, xsh:substr,
xsh:sum, xsh:times, xsh:uc, xsh:ucfirst, xsh:var
END
$HELP{'command'}=[<<'END'];
command
description:
XSH2 command consists of a command name and possibly command
parameters separated by whitespace. Individual [XSH2 commands]
are separated with a semicolon. A command may optionally be
followed by an output redirection directive (see
[binding_shell] for output redirection to a command and
[Variables] for output redirection to variable). Most commands
have aliases, so for example [remove] command may also be
invoked as 'del' or 'rm'.
XSH2 recognizes the following commands (not including
aliases): apropos, assign, backups, call, canonical, catalog,
cd, change-ns-prefix, change-ns-uri, clone, close, copy,
count, create, debug, declare-ns, def, defs, do, doc-info,
documents, dtd, edit, edit-string, empty-tags, enc, encoding,
eval, exec, exit, fold, foreach, get, hash, help, if,
ifinclude, include, indent, index, insert, iterate,
keep-blanks, last, lcd, lineno, load-ext-dtd, local, locate,
ls, map, move, my, namespaces, next, nobackups, nodebug,
normalize, open, parser-completes-attributes,
parser-expands-entities, parser-expands-xinclude,
pedantic-parser, perl, prev, print, process-xinclude, pwd,
query-encoding, quiet, recovering, redo, register-function,
register-namespace, register-xhtml-namespace,
register-xsh-namespace, remove, rename, return, run-mode,
save, set, set-dtd, set-enc, set-ns, set-standalone,
set_filename, settings, skip-dtd, sort, stream,
strip-whitespace, switch-to-new-documents, test-mode, throw,
try, undef, unfold, unless, unregister-function,
unregister-namespace, validate, validation, variables,
verbose, version, while, wrap, wrap-span, xcopy, xinsert,
xmove, xpath-axis-completion, xpath-completion,
xpath-extensions, xslt, xupdate
see also: block
END
$HELP{'block'}=[<<'END'];
block argument type
description:
a block of semicolon-separated XSH2 commands enclosed within
braces.
Example: Count paragraphs in each chapter
$i=0;
foreach //chapter {
$c=count(./para);
$i=$i+1;
print "$c paragraphs in chapter no.$i";
}
END
$HELP{'type'}=[<<'END'];
List of command argument types
description:
$variable, block, command, document, encoding, expression,
filename, location, node-type, nodename, perl-code,
subroutine, xpath
END
$HELP{'encoding'}=[<<'END'];
enc_string argument type
description:
An [expression] which evaluates to a valid encoding name, e.g.
to utf-8, utf-16, iso-8859-1, iso-8859-2, windows-1250 etc. As
with [filename], as long as the expression doesn't contain
special characters like braces, brackets, quotes, '$', nor
'@', it is taken as a literal and evaluates to itself.
END
$HELP{'$variable'}=[<<'END'];
variable name
description:
Variable names start with a dollar-sign ('$') followed by an
identifier. The identifier must match the following regular
expression '[a-zA-Z_][a-zA-Z0-9_]*', i.e., it must be at least
one character long, must beginning with a letter or
underscore, and may only containing letters, underscores, and
digits.
see also: Variables assign my local
END
$HELP{'subroutine'}=[<<'END'];
sub-routine name
description:
A sub-routine name is an identifier matching the following
regular expression '[a-zA-Z_][a-zA-Z0-9_]*', i.e., it must be
at least one character long, must beginning with a letter or
underscore, and may only containing letters, underscores, and
digits.
END
$HELP{'document'}=[<<'END'];
document
description:
A document is specified by arbitrary [expression] which
evaluates to a non-empty node-list. From this node-list, the
first node is taken and its owner document is used.
see also: Variables assign my local
END
$HELP{'filename'}=[<<'END'];
Filename argument type
description:
An [expression] which evaluates to a valid filename or URL. As
long as the expression contains no whitespace, no brackets of
any type, quotes, double-quotes, '$' character nor '@'
character, it is treated as a literal token which evaluates to
itself.
END
$HELP{'nodename'}=[<<'END'];
Node-name argument type
description:
An [expression] which evaluates to a valid name of an element,
attribute or processing-instruction node. As long as the
expression contains no whitespace, no brackets of any type,
quotes, double-quotes, '$' character, nor '@' character, it is
treated as a literal token which evaluates to itself.
END
$HELP{'xpath'}=[<<'END'];
XPath argument type
description:
XSH2 can evaluate XPath expressions as defined in W3C
recommendation at http://www.w3.org/TR/xpath with only a
little limitation on use of syntactically ignorable
whitespace. (Nice interactive XPath tutorials and references
can be found at http://www.zvon.org.)
In order to allow XSH2 to use white-space as a command
argument delimiter (which is far more convenient to type than,
say, commas), the use of white-space in XPath is slightly
restricted. Thus, in XSH2, white-space can only occur in those
parts of an XPath expression, that are surrounded by either
brackets, square brackets, single or double quotes. So, for
example, otherwise valid XPath expression like
/ foo / bar [ @baz = "bar" ]
should in XSH2 be written as either of
/foo/bar[ @baz = "bar" ]
avoiding any white-space outside the square brackets, or
completely enclosed in brackets as in
( / foo / bar [ @baz = "bar" ] ).
XSH2 provides a number of powerful XPath extension functions,
listed below and described in separate sections. XPath
extension functions by default belong to XSH2 namespace
'http://xsh.sourceforge.net/xsh/' with a namespace prefix set
to 'xsh'. A program may however call the [xpath-extensions]
command to map XSH2 XPath extension functions into the default
namespace, so that they may be used directly without any
prefix.
XPath extension functions defined in XSH2: xsh:base-uri,
xsh:context, xsh:current, xsh:doc, xsh:document,
xsh:document-uri, xsh:documents, xsh:evaluate, xsh:filename,
xsh:grep, xsh:id2, xsh:if, xsh:join, xsh:lc, xsh:lcfirst,
xsh:lineno, xsh:lookup, xsh:map, xsh:match, xsh:matches,
xsh:max, xsh:min, xsh:new-attribute, xsh:new-cdata,
xsh:new-chunk, xsh:new-comment, xsh:new-element,
xsh:new-element-ns, xsh:new-pi, xsh:new-text, xsh:parse,
xsh:path, xsh:resolve-uri, xsh:reverse, xsh:same,
xsh:serialize, xsh:span, xsh:split, xsh:sprintf, xsh:strmax,
xsh:strmin, xsh:subst, xsh:substr, xsh:sum, xsh:times, xsh:uc,
xsh:ucfirst, xsh:var
Example: Open a document and count all sections containing a subsection
xsh $scratch/> $v := open mydocument1.xml;
xsh $v/> $k := open mydocument2.xml;
xsh $k/> count //section[subsection]; # searches k
xsh $k/> count $v//section[subsection]; # searches v
END
$HELP{'expression'}=[<<'END'];
expression
description:
An XSH2 expression can be one of the following constructs:
1. XPath 1.0 expression with the following restriction:
whitespace is only allowed within parts the expression
enclosed in quotes (literal strings) or brackets (XPath has
two types of brackets - plain and square). Thus, while '/
foo / bar' is a valid XPath expression matching element
named bar under root element foo, in XSH2 this expression
must be written as '/foo/bar' or '(/ foo / bar)' or
'(/foo/bar)' etc. The reason for this restriction is simple:
XSH2, like most shell languages, uses whitespace as argument
delimiter so it must be able to determine expression
boundaries (otherwise, '/ bar / foo' could be anything
between one and four expressions).
2. In certain contexts, usually when a filename or a node
name is expected as an argument, bareword (otherwise XPath)
expressions are evaluated in a non-standard way: as long as
the expression contains no whitespace, no brackets of any
kind, quotes, double-quotes, '$' character, nor '@'
character, it is treated as a literal token which evaluates
to itself. This usually happens if a file name or element
name is expected, but some other commands, like [print],
evaluate its arguments in this way. In order to force an
XPath evaluation in such situations, the entire expression
should be enclosed with brackets '(...)'. For example, with
[open] command, 'open file' or 'open "file"' both open a
file whose name is 'file' (literally) whereas 'open (file)'
or 'open @file' compute the file name by evaluating '(file)'
or '@file' respectively, as XPath expressions.
3. Perl blocks. These are enclosed in braces like: '{
perl-code }'. Perl expressions can be used to evaluate more
complicated things, like complex string expressions, regexp
matches, perl commands, etc. In short, arbitrary perl. Of
course, things like '{`ls`}' work too, and that's why we
don't need to define shell-like backticks in XSH2 itself.
4. Result of one XSH2 command can be directly passed as an
argument to another. This is done using &{ xsh-code }
expressions. Most XSH2 commands always return 'undef' or 1,
but some do return a value, usually a node-list. Examples of
such commands are [open], [copy], [move], [wrap], [edit], or
[xslt].
5. Large blocks of literal data can be passed to commands
via "here document" expressions '<<EOF', '<<'EOF'',
<<"EOF"'', where 'EOF' is an arbitrary 'ID' string. '<<EOF'
and '<<"EOF"' are equivalent, and are subject to
interpolation of '${...}' constructs, where as '<<'EOF''
does not. The result of evaluation of these three is the
literal content (with '${...}' possibly interpolated) of the
script starting at the following line and ending at a line
containing just 'EOF'. '<<{EOF}' and '<<(EOF)' are
implemented too, but I'm not sure they are of any use since
putting the expression in ( ) or { } has the same effect.
XPath expressions (and their filename variant) are subject to
interpolation of substrings of the form '${...}' (called
interpolators), where '...' can be of several different forms,
described below. The interpolation can be suppressed by
preceding the '$' sign with a backslash.
Substrings of the form '${id}' or '${$id}' are interpolated
with the value of the variable named '$id'.
Interpolators of the form '${{' and '}}' evaluate their
contents as a Perl expression (in very much the same way as
the [perl] command) and interpolate to the resulting value.
Interpolators of the form '${(' and ')}' evaluate their
contents as an XPath expression and interpolates to a string
value of the result.
Substrings of the form '\${' interpolate to '${' (as a means
for escaping '${...}' in an expression).
Expressions are evaluated by XSH2 commands themselves, so the
exact value an expression evaluates to, is also
command-dependent. There are commands that can handle all data
types, but some commands expect their arguments to evaluate
only to specific kinds of values. As already mentioned above,
commands expecting a filename or a node name usually evaluate
simple expressions not containing any special characters as
literal strings, whereas commands expecting strings evaluate
all expressions so that they get a string value (e.g. by
converting a node-set to its text content). Similarly,
commands expecting a node-set usually convert strings to a
small XML fragments, while commands expecting a single
document node usually convert node-sets to a document node by
taking the owner document of the first element in the
node-set.
Example:
$a = "bar"; # $a contains: bar
$b = $a; # $b contains: bar
$b = "$a"; # $b contains: $a
$b = "${a}"; # $b contains: bar
$b = {$a}; # $b contains: bar
$b = //creature; # $b contains a node-set
ls $b; # prints the node-set as XML in document order
count $b; # prints number of nodes in the node-set
echo count($b); # the same
$c = string($b[1]/@name) # $c contains string value of //creature[1]/@name (e.g. Bilbo)
echo //creature # prints: //creature
echo (//creature) # evaluates (//creature) as XPath and prints the
# text content of the resulting node-set
echo { join(",",split(//,$a)) } # prints: b,a,r
echo ${{ join(",",split(//,$a)) }} # the same
echo "${{ join(",",split(//,$a)) }}" # the same
echo "${(//creature[1]/@name)}" # prints e.g.: Bilbo
echo ${(//creature[1]/@name)} # the same
echo //creature[1]/@name # the same
echo string(//creature[1]/@name) # the same
echo (//creature[1]/@name) # the same
Example: In-line documents
$a="bar"
echo foo <<END baz;
xx ${a} yy
END
# prints foo xx bar yy baz
echo foo <<"END" baz;
xx ${a} yy
END
# same as above
echo foo <<'END' baz;
xx ${a} yy
END
# prints foo xx $a yy baz
Example: Expressions returning result of a XSH2 command
copy &{ sort --key @best_score --numeric //player } into .;
END
$HELP{'try'}=[<<'END'];
usage: try [block] catch [[local|my] [$variable]] [block]
description:
Execute the [block] following the 'try' keyword. If an error
or exception occurs during the evaluation, execute the 'catch'
[block]. If the 'catch' keyword is followed by a variable
(possibly localized for the following block using [my] or
[local]) and the 'try' block fails with an exception, the
error message of the exception is stored to the variable
before the 'catch' block is executed.
The [throw] command as well as an equivalent Perl construction
'perl { die "error message" }' allow user to throw custom
exceptions.
Unless exception is raised or error occurs, this command
returns the return value of the 'try' block; otherwise it
returns the return value of the 'catch' block.
Example: Handle parse errors
try {
$doc:=open --format xml $input;
} catch {
try {
echo "XML parser failed, trying HTML";
$doc := open --format html $input;
} catch my $error {
echo "Stopping due to errors: $error";
exit 1;
}
}
see also: throw
END
$HELP{'if'}=[<<'END'];
usage: if [expression] [command]
if [expression]
[block] [ elsif [block] ]* [ else [block] ]
description:
Executes [command] or [block] if a given [expression]
expression evaluates to a non-emtpty node-list, true
boolean-value, non-zero number or non-empty literal. If the
first expression fails, then 'elsif' conditions are tested (if
any) and the [block] corresponding to the first one of them
which is true is executed. If none of the conditions is
satisfied, an optional 'else' [block] is executed.
Example: Display node type
def node_type %n {
foreach (%n) {
if ( . = self::* ) { # XPath trick to check if . is an element
echo 'element';
} elsif ( . = ../@* ) { # XPath trick to check if . is an attribute
echo 'attribute';
} elsif ( . = ../processing-instruction() ) {
echo 'pi';
} elsif ( . = ../text() ) {
echo 'text';
} elsif ( . = ../comment() ) {
echo 'comment'
} else { # well, this should not happen, but anyway, ...
echo 'unknown-type';
}
}
}
Example: Check a environment variable
if { defined($ENV{HOME}) } lcd { $ENV{HOME} }
END
$HELP{'unless'}=[<<'END'];
usage: unless [expression]
[command]
unless [expression]
[block] [ else [block] ]
description:
Like if but negating the result of the expression. Also,
unlike if, 'unless' has no 'elsif' block.
see also: if
END
$HELP{'while'}=[<<'END'];
usage: while [expression] [block]
description:
Execute the [command] or [block] as long as the given
[expression] evaluates to a non-emtpty node-list, true
boolean-value, non-zero number or non-empty literal.
Example: The commands in this example do the same thing
xsh> while /table/row remove /table/row[1];
xsh> remove /table/row;
END
$HELP{'do'}=[<<'END'];
usage: do [block]
description:
Execute [block]. This command is probably only useful when one
wants to redirect output of more than one command.
see also: block
END
$HELP{'eval'}=[<<'END'];
usage: eval [expression]
description:
NOTE: This command has very different behavior from XSH1,
where it used to be an alias for [perl].
This command first evaluates a given [expression] to obtain a
string, then evaluates this string as XSH2 code in the current
context, returning the return value of the last evaluated
command. This command raises an exception if either
[expression] evaluates to invalid XSH2 code or if evaluating
the code raises an exception.
Example: Evaluate "in-line" XSH snippets within a XML document
foreach //inline-xsh eval .;
END
$HELP{'foreach'}=[<<'END'];
usage: foreach [expression]
[command]|[block]
foreach [my|local] [$variable] in [expression]
[command]|[block]
aliases: for
description:
Evaluate given [expression] to a node-list and for each
resulting node execute given [command] or [block]. If used
without a loop [$variable], the loop temporarily sets current
node to the node being processed. Otherwise, the processed
node is assigned to the loop variable.
The [expression] may be [xpath] as well as a [perl-code]. In
the latter case, if used without a loop variable, the loop
automatically converts Perl objects to nodes. No conversion is
performed when a loop variable is used.
Example: Move all employee sub-elements in a company element into the
first staff subelement of the same company
xsh> foreach //company xmove employee into staff[1];
Example: List content of all XML files in current directory
xsh> foreach my $filename in { glob('*.xml') } {
$f := open $filename;
do_something $f;
}
END
$HELP{'for'}=$HELP{'foreach'};
$HELP{'undef'}=[<<'END'];
usage: undef [[subroutine] | [$variable]]
aliases: undefine
description:
This command can be used to undefine previously defined XSH2
subroutines and variables.
see also: close def
END
$HELP{'undefine'}=$HELP{'undef'};
$HELP{'def'}=[<<'END'];
usage: def [subroutine] [[$variable] ...] [block]
aliases: define
description:
Define a new XSH2 sub-routine named [subroutine]. The
subroutine may require zero or more parameters. These are
declared as a whitespace-separated list of parametric
variables. The body of the subroutine is specified as a
[block].
A sub-routine can be invoked directly by its name followed by
its arguments just as any XSH2 command, or indirectly using
the [call] command followed by an expression evaluating to the
routine name and sub-routine arguments. Sub-routine arguments
can be arbitrary expressions. These expressions are evaluated
prior the sub-routine's code execution and are assigned to the
sub-routine's parametric variables in the respective order.
The number of parameter variables in a sub-routine definition
and the number of arguments in a call to it must match.
Calling a sub-routine with less or more arguments than
declared is a run-time error.
Parametric variables are lexical variables within the
sub-routine body as if they were declared with [my].
Note that a subroutine has to be defined before it is first
called (in terms of execution -- depending on the structure of
the program, the actual definition of the sub-routine must not
necessarily precede all references to it).
Example:
def l3 $nodes {
ls --depth 3 $nodes; # list given nodes upto depth 3
}
l3 //chapter; # direct call
$subref = 'l3';
call $subref //chapter; # in-direct call
Example: Commenting and un-commenting pieces of document
def comment
$n # nodes to move to comments
$mark # maybe some handy mark to recognize such comments
{
foreach $n {
if ( . = ../@* ) {
echo "Warning: attribute nodes are not supported!";
} else {
echo "Commenting out:";
ls --depth 0 .;
add comment concat($mark,xsh:serialize(.)) replace .;
}
}
}
def uncomment $n $mark {
foreach $n {
if (. = ../comment()) { # is this node a comment node
local $string = substring-after(.,"$mark");
add chunk $string replace .;
} else {
echo "Warning: Ignoring non-comment node:";
ls --depth 0 .;
}
}
}
# comment out all chapters with no paragraphs
comment //chapter[not(para)] "COMMENT-NOPARA";
# uncomment all comments stamped with COMMENT-NOPARA
$mark="COMMENT-NOPARA";
uncomment //comment()[starts-with(.,"$mark")] $mark;
see also: call return my local
END
$HELP{'define'}=$HELP{'def'};
$HELP{'assign'}=[<<'END'];
usage: [assign] [$variable] = [expression]
[assign] [$variable] := [command]
[assign] [$variable] [-= | += | *= | /= | %= | x= | .= | ||= | &&= ] [expression]
[assign] [$variable] [-:= | +:= | *:= | /:= | %:= | x:= | .:= | ||:= | &&:= ] [command]
description:
Evaluate the expression (= assignment) or command (:=
assignment) on the right side of the assignment and store the
result in a given variable. Optionally a Perl operator (-
subtraction, + addition, * multiplication, / division, %
modulo, x repeat string n-times, . concatenation, || logical
OR, && logical AND) can precede the assignment, in which case
the variable is assigned the result of applying given operator
on its previous value and the value of the right side of the
assignment.
Example: Assign XPath (node-set, string), or Perl results
xsh> $a=chapter/title;
xsh> $b="hallo world";
xsh> $c={ `uname` };
xsh> ls $a;
Example: Arithmetic expressions (XPath)
xsh> $a=5*100 # assign 500 to $a
xsh> $a += 20 # add 20 to $a
xsh> $a = (($a+5) div 10)
Example: Arithmetic expressions (Perl)
xsh> $a={ 5*100 }
xsh> $a = { join ';', split //,"hallo" } # assigns "h;a;l;l;o" to $a
Example: Command result assignment
xsh> $doc := open "file.xml" # open a document
xsh> $copies := xcopy //foo into //bar # copy elements and store the copies
xsh> $wrappers := wrap "wrapper" $copies # wrap each node from $copies to a new element "wrapper" and store the wrapping elements
see also: variables
END
$HELP{'my'}=[<<'END'];
usage: my [$variable] [$var2 ...];
my [$variable] = [expression];
description:
Same as in Perl: a "my" declares the listed variables to be
local (lexically) to the enclosing block, or sub-routine.
see also: local
END
$HELP{'local'}=[<<'END'];
usage: local [$variable] = [xpath]
local [$variable] [ [$variable] ... ]
description:
This command acts in a very similar way as [assign] does,
except that the variable assignment is done temporarily and
lasts only for the rest of its enclosing [block] or
subroutine. At the end of the enclosing block or subroutine,
the original value is restored. This also reverts any later
usual assignments to the variable done occurring before the
end of the block. This command may also be used without the
assignment part.
Note, that the variable itself remains global in the sense
that it is still visible to any subroutine called subsequently
from the same block. Unlike [my] declaration, it does not
create a new lexically scoped variable.
Hint for Perl programmers: 'local' in XSH2 works exactly as
'local' in Perl.
see also: assign my def
END
$HELP{'settings'}=[<<'END'];
usage: settings
description:
List current values of all XSH2 settings (such as validation
flag or query-encoding).
'--variables' or ':v' flag enforces syntax which makes use of
variable assignments. Otherwise, settings are listed in the
form of XSH commands.
Example: Store current settings in your .xsh2rc
xsh> settings | cat > ~/.xsh2rc
END
$HELP{'defs'}=[<<'END'];
usage: defs
description:
List names and parametric variables for all user-defined XSH2
subroutines.
see also: def variables
END
$HELP{'ifinclude'}=[<<'END'];
usage: ifinclude [--encoding|:e [encoding]] [filename]
description:
Unless the file [filename] has already been included using
either [include] of [ifinclude], load the file and execute it
as a XSH2 script.
Use '--encoding' or ':e' parameter to specify character
encoding used in the included file.
see also: include
END
$HELP{'include'}=[<<'END'];
usage: include [--encoding|:e [encoding]] [filename]
aliases: .
description:
Load a file named [filename] and execute it as a XSH2 script.
Use '--encoding' or ':e' parameter to specify character
encoding used in the included file.
see also: ifinclude
END
$HELP{'.'}=$HELP{'include'};
$HELP{'apropos'}=[<<'END'];
usage: apropos [--fulltext] [--regexp] [expression]
description:
Print all help topics containing given expression in their
short description. The '--fulltext' flag forces the search to
be performed over the full text of help. '--regexp' indicates,
that the given [expression] is a regular expression instead of
a literal string.
END
$HELP{'help'}=[<<'END'];
usage: help [command]|argument-type|xsh:xpath-function
description:
Print help on a given command, argument type or XPath
extension function (use 'xsh:' as a prefix to XPath extensions
function names, e.g 'help xsh:id2').
END
$HELP{'exec'}=[<<'END'];
usage: exec [expression] [[expression] ...]
aliases: system
description:
This command executes given [expression](s) as a system
command and returns the exit code.
Example: Count words in "hallo wold" string, then print name of your
machine's operating system.
exec echo hallo world; # prints hallo world
exec "echo hallo word" | wc; # counts words in hallo world
exec uname; # prints operating system name
END
$HELP{'system'}=$HELP{'exec'};
$HELP{'xslt'}=[<<'END'];
usage: $result := xslt [--doc|:d | --precompiled|:p] [--string] [expression] [[document] name=[xpath] [name=[xpath] ...]]
$pre_compiled := xslt [--compile|:c] [expression]
aliases: transform xsl xsltproc process
description:
This function compiles a given XSLT stylesheet and/or
transforms a given document with XSLT.
A XSLT stylesheet is specified in the first argument either as
a file name (default), or as a document ('--doc' or ':d'), or
as a precompiled XSLT stylesheet object ('--precompiled' or
':p' - see '--compile' above).
If '--compile' or ':c' is used, compile a given XSLT
stylesheet and return a compiled XSLT stylesheet object. This
object can be later passed as a XSLT stylesheet to 'xslt
--precompiled'.
Without '--compile' or ':c', transform a given [document] (or
- if used with only the stylesheet argument - the current
document) using a given XSLT stylesheet and return the result.
All arguments following the second (document) argument are
considered to be stylesheet parameters and (after expanding
'${...}' interpolators) are directly passed to the XSLT engine
without being evaluated by XSH2. All stylesheet parameters
should be of the form 'name=[xpath]' (possibly in brackets).
Example: Process current document with XSLT
$result := xslt stylesheet.xsl . font='14pt' color='red'
Example: Same for several documents, reusing the XSLT stylesheet
$xslt := xslt --compile stylesheet.xsl;
foreach my $file in {qw(f1.xml f2.xml f3.xml)} {
save --file {"out_$file"} &{xslt --precompiled $xslt &{ open $file } font='14pt' color='red'};
}
END
$HELP{'transform'}=$HELP{'xslt'};
$HELP{'xsl'}=$HELP{'xslt'};
$HELP{'xsltproc'}=$HELP{'xslt'};
$HELP{'process'}=$HELP{'xslt'};
$HELP{'documents'}=[<<'END'];
usage: documents
aliases: files docs
description:
Try to identify open documents and list their URIs and
variables that contain them.
see also: open close
END
$HELP{'files'}=$HELP{'documents'};
$HELP{'docs'}=$HELP{'documents'};
$HELP{'set_filename'}=[<<'END'];
usage: set_filename [expression] [[document]]
description:
Changes filename or URL associated with a given document (or
the current document, if only one argument is specified).
Document filename is initialized by the [open] command and
used e.g. by [save]. It can be queried in XPath expressions
using the [xsh:filename] function.
see also: open save xsh:filename
END
$HELP{'variables'}=[<<'END'];
usage: variables
aliases: vars var
description:
List all global variables and their current values.
see also: documents defs
END
$HELP{'vars'}=$HELP{'variables'};
$HELP{'var'}=$HELP{'variables'};
$HELP{'copy'}=[<<'END'];
usage: copy [--respective|:r] [expression] [location] [expression]
$results := copy [--respective|:r] [expression] [location] [expression]
aliases: cp
description:
Copies nodes in the first node-list [expression] (source
nodes) to the destinations determined by the the [location]
directive applied to nodes in the second node-list
[expression] (target nodes). If the source node-list contains
more than one node, than N'th node in the source node-list is
copied to the location relative to the N'th node in the target
node-list.
If '--respective|:r' option is used, then the target node-list
[expression] is evaluated in the context of the source node
being copied.
Possible values for [location] are: 'after', 'before', 'into',
'replace', 'append' and 'prepend'. The first three location
directives cause making a copy of the source nodes after,
before, and within (as the last child-node) the target nodes,
respectively. If 'replace' location directive is used, source
node are copied before the respective target nodes and target
nodes are removed. The 'append' and 'prepend' location
directives allow, depending on the destination node type,
either inserting copies of the source nodes as the first or
last child nodes of a destination element or
appending/prepending destination node data in case of
non-element destination nodes. See [location] argument type
for more detail.
The command returns a node-list consisting of the copies of
all source nodes created by the command.
Despite the fact the command is named "copy", nodes resulting
from copying the source nodes may pass through certain type
conversion before they are inserted at the appointed
destinations. This, however, only happens in cases where the
types of the source and target nodes are not compatible with
the location directive. See [location] argument type for more
detail.
Note that XSH2 refuses to create multiple top-level elements
using 'copy', [move] and similar commands.
Example: Replace living-thing elements in the document b with copies of
the corresponding creature elements from the document $a.
xsh> copy $a//creature replace $b//living-thing
Example: Copy every element into itself
xsh> copy --respective $a//* into .
xsh> copy $a//* into $a//* #same as
above
see also: xcopy move xmove insert xinsert
END
$HELP{'cp'}=$HELP{'copy'};
$HELP{'xcopy'}=[<<'END'];
usage: xcopy [--respective|:r] [--preserve-order|:p] [expression] [location] [expression]
aliases: xcp
description:
xcopy is similar to [copy], but copies all nodes in the first
node-list [expression] to all destinations determined by the
[location] directive relative to the second node-list
[expression]. See [copy] for detailed description of 'xcopy'
arguments.
If '--respective|:r' option is used, then the target node-list
[expression] is evaluated in the context of the source node
being copied.
The '--preserve-order|:p' option can be used to ensure that
the copied nodes are in the same relative order as the
corresponding source nodes. Otherwise, if [location] is
'after' or 'prepend', the relative order of the copied nodes
will be reversed, because source nodes are placed to the
target location one by one.
Example: Copy all middle-earth creatures within the document $a into
every world of the document $b.
xsh> xcopy $a/middle-earth/creature into $b//world
see also: copy move xmove insert xinsert
END
$HELP{'xcp'}=$HELP{'xcopy'};
$HELP{'lcd'}=[<<'END'];
usage: lcd [expression]
aliases: chdir
description:
Changes the filesystem working directory to [expression], if
possible. If [expression] is omitted, changes to the directory
specified in HOME environment variable, if set; if not,
changes to the directory specified by LOGDIR environment
variable.
END
$HELP{'chdir'}=$HELP{'lcd'};
$HELP{'insert'}=[<<'END'];
usage: insert [--namespace|:n [expression]] [node-type] [expression] [location] [xpath]
aliases: add
description:
Works just like [xinsert], except that the new node is
attached only the first node matched.
see also: xinsert move xmove
END
$HELP{'add'}=$HELP{'insert'};
$HELP{'wrap'}=[<<'END'];
usage: wrap [--namespace [expression]]
[ [--inner] | [--while|:W [expression]] [--until|:U [expression]]
[--skip-whitespace|:w] [--skip-comments|:c] [--skip-pi|:p] ]
[expression] [xpath]
description:
For each node matching the [xpath] argument, this command
creates a new element node according to a given [expression]
(in the same way as [xinsert] does) which replaces the
matching node, and moves the matching node into this newly
created element. If namespace [expression] is given, the
namespace is applied on the created element. The command
returns a node-list consisting of the elements created.
With '--inner' (or ':i') flag the command wraps children nodes
of the matching node rather than the node it self the
following sense: for each matching node a new element node is
created, but this time it is placed into the matching node and
all previous children of the matching node are moved into the
newly created node. In this mode, all non-element matching
nodes are ignored. This flag cannot be used together with
'--while' and '--until', which we describe next.
'--while' (':W') and/or '--until' (':U') arguments can be
provided in order to move a sequence of adjacent siblings
following the matching node into the newly created element. In
this way the newly created element wraps not just the matching
node itself but a range of nodes starting at the matching node
and ending either before a first following node matching the
expression of '--until', or before a first following node not
matching the expression of '--while', or at the last sibling
if neither of the prior apply. Both these expressions are
evaluated in the context of the currently tested sibling and
prior to the creation of the wrapping element. The context
position for these expressions is 1 at the first sibling
following the matching node and increases with each tested
sibling; the context size is the number of all siblings
following the matching node. It is important to mention that
siblings wrapped in this way are excluded from further
processing by [wrap] even if included in the node-list
produced by the [xpath] argument. This allows to easily wrap
certain adjacent elements without worrying about some elements
being wrapped multiple times (for example, 'wrap :W x y //x'
wraps each sequence of adjacent elements '<x>' in a '<y>').
'--skip-whitespace' (':w'), '--skip-comments' (':c'), and
'--skip-pi' (':p') can be used in combination with '--while'
(':W') and/or '--until' (':U') to skip testing the expressions
on white-space text nodes, comments, and/or processing
instruction, respectively. Such nodes are only included in the
wrapped range if followed by a sibling that is to be wrapped.
Example:
$scratch/> ls /;
<?xml version="1.0" encoding="utf-8"?>
<scratch/>
$scratch/> wrap 'foo' *;
$scratch/> insert attribute 'bar=baz' into /foo;
$scratch/> insert text 'some text' into //scratch;
$scratch/> wrap --namespace 'http://foo/bar' 'a:A' //@*;
$scratch/> $wrapper := wrap 'text aaa="bbb"' //text();
$scratch/> wrap '<elem ccc=ddd>' //*;
$scratch/> ls /;
<?xml version="1.0" encoding="utf-8"?>
<elem ccc="ddd">
<foo xmlns:a="http://foo/bar">
<elem ccc="ddd">
<scratch>
<elem ccc="ddd">
<text aaa="bbb">some text</text>
</elem>
</scratch>
</elem>
<elem ccc="ddd">
<a:A xmlns:a="http://foo/bar" bar="baz"/>
</elem>
</foo>
</elem>
$scratch/> ls $wrapper;
<text aaa="bbb">some text</text>
$scratch/> wrap --inner bar //foo
$scratch/> ls /;
<?xml version="1.0" encoding="utf-8"?>
<elem ccc="ddd">
<foo xmlns:a="http://foo/bar">
<bar>
<elem ccc="ddd">
<scratch>
<elem ccc="ddd">
<text aaa="bbb">some text</text>
</elem>
</scratch>
</elem>
<elem ccc="ddd">
<a:A xmlns:a="http://foo/bar" bar="baz"/>
</elem>
</bar>
</foo>
</elem>
Example: Wrapping a range of adjacent nodes
# prepare the test document
$scratch/> rm /scratch/node(); # cleanup the document
$scratch/> set /scratch/li[5]; # create 5 <li> elements
$scratch/> set /scratch/li[3]/following-sibling::li; # add <br/> after the 3rd <li>
$scratch/> for //li set . position(); # number the <li> elements
$scratch/> ls /
<?xml version="1.0" encoding="utf-8"?>
<scratch>
<li>1</li>
<li>2</li>
<li>3</li>
<br/>
<li>4</li>
<li>5</li>
</scratch>
# wrap adjacent elements <li> into an <ol>
$scratch/> wrap --skip-whitespace --while self::li ol //li;
$scratch/> ls /
<?xml version="1.0" encoding="utf-8"?>
<scratch>
<ol>
<li>1</li>
<li>2</li>
<li>3</li>
</ol>
<br/>
<ol>
<li>4</li>
<li>5</li>
</ol>
</scratch>
see also: xinsert insert move xmove
END
$HELP{'wrap-span'}=[<<'END'];
usage: wrap-span [--namespace [expression]] [expression] [expression] [expression]
aliases: wrap_span
description:
This command is very similar to [wrap] command, except that it
works on spans of nodes. It wraps spans (i.e. sequence of
adjacent nodes between (and including) a start node and an end
node) with a new element whose name is specified as the first
argument. Nodes within each span must have the same parent
node. The spans to be wrapped are defined by a pair of
node-lists in the second and third argument. The first
node-list specifies the start node of one or more spans, while
the second node-list should contain the corresponding end
nodes. The two node-lists must evaluate to the exactly same
number of nodes, otherwise a runtime error is reported. The
N'th span is then defined as a span starting on the N'th node
in the start node-list and ending at the N'th node in the end
node-list.
All nodes within the spans are removed from the document and
placed into the newly generated elements. The wrapping
elements are put back into the document tree at the positions
previously occupied by the node-spans.
The command returns a node-list containing the newly created
wrapping elements.
Example:
xsh $scratch/> $foo := create { "<root>\n<a/><b/>\n<a/><b/>\n<a/><b/>\n</root>" };
xsh $foo/> wrap-span 'span' //a //b;
xsh $foo/> ls /;
<?xml version="1.0" encoding="utf-8"?>
<root>
<span><a/><b/></span>
<span><a/><b/></span>
<span><a/><b/></span>
</root>
see also: xinsert insert move xmove
END
$HELP{'wrap_span'}=$HELP{'wrap-span'};
$HELP{'xinsert'}=[<<'END'];
usage: xinsert [--namespace [expression]] [node-type] [expression] [location] [xpath]
aliases: xadd
description:
Create new nodes of the [node-type] given in the 1st argument
of name specified in the 2nd argument and insert them to
[location]s relative to nodes in the node-list specified in
the 4th argument.
For element nodes, the the 2nd argument [expression] should
evaluate to something like "<element-name att-name='attvalue'
...>". The '<' and '>' characters are optional. If no
attributes are used, the expression may simply consist the
element name. Note, that in the first case, the quotes are
required since the expression contains spaces.
Attribute nodes use the following syntax: "att-name='attvalue'
[...]".
For the other types of nodes (text, cdata, comments) the
expression should contain the node's literal content. Again,
it is necessary to quote all whitespace and special characters
as in any expression argument.
The [location] argument should be one of: 'after', 'before',
'into', 'replace', 'append' or 'prepend'. See documentation of
the [location] argument type for more detail.
Optionally, for element and attribute nodes, a namespace may
be specified with '--namespace' or ':n'. If used, the
expression should evaluate to the desired namespace URI and
the name of the element or attribute being inserted must have
a prefix.
The command returns a node-list consisting of nodes it
created.
Note, that instead of 'xinsert', you can alternatively use one
of [xsh:new-attribute], [xsh:new-cdata], [xsh:new-chunk],
[xsh:new-comment], [xsh:new-element], [xsh:new-element-ns],
[xsh:new-pi], and [xsh:new-text] together with the command
[xcopy].
Example: Give each chapter a provisional title element.
xsh> my $new_titles := xinsert element "<title font-size=large underline=yes>" \
into /book/chapter
xsh> xinsert text "Change me!" into $new_titles;
Example: Same as above, using xcopy and xsh:new-... instead of xinsert
xsh> my $new_titles := xcopy xsh:new-element("title","font-size","large","underline","yes") \
into /book/chapter
xsh> xcopy xsh:new-text("Change me!") into $new_titles;
see also: insert move xmove
END
$HELP{'xadd'}=$HELP{'xinsert'};
$HELP{'node-type'}=[<<'END'];
Node-type argument type
description:
One of: element, attribute, text, cdata, comment, chunk and
(EXPERIMENTALLY!) entity_reference. A chunk is a character
string which forms a well-balanced piece of XML.
Example:
add element hobbit into //middle-earth/creatures;
add attribute 'name="Bilbo"' into //middle-earth/creatures/hobbit[last()];
add chunk '<hobbit name="Frodo">A small guy from <place>Shire</place>.</hobbit>'
into //middle-earth/creatures;
END
$HELP{'location'}=[<<'END'];
Location argument type
description:
One of: 'after', 'before', 'into', 'append', 'prepend',
'replace'.
This argument is required by all commands that insert nodes to
a document in some way to a destination described by an XPath
expression. The meaning of the values listed above is supposed
be obvious in most cases, however the exact semantics for
location argument values depends on types of both the source
node and the target node.
'after/before' place the node right after/before the
destination node, except for when the destination node is a
document node or one of the source nodes is an attribute: If
the destination node is a document node, the source node is
attached to the end/beginning of the document (remember: there
is no "after/before a document"). If both the source and
destination nodes are attributes, then the source node is
simply attached to the element containing the destination node
(remember: there is no order on attribute nodes). If the
destination node is an attribute but the source node is of a
different type, then the textual content of the source node is
appended to the value of the destination attribute (i.e. in
this case after/before act just as append/prepend).
'append/prepend' appends/prepends the source node to the
destination node. If the destination node can contain other
nodes (i.e. it is an element or a document node) then the
entire source node is attached to it. In case of other
destination node types, the textual content of the source node
is appended/prepended to the content of the destination node.
'into' can also be used to place the source node to the end of
an element (in the same way as 'append'), to attach an
attribute to an element, or, if the destination node is a text
node, cdata section, processing-instruction, attribute or
comment, to replace its textual content with the textual
content of the source node.
'replace' replaces the entire destination node with the source
node except for the case when the destination node is an
attribute and the source node is not. In such a case only the
value of the destination attribute is replaced with the
textual content of the source node. Note also that document
node can never be replaced.
END
$HELP{'move'}=[<<'END'];
usage: move [xpath] [location] [xpath]
aliases: mv
description:
'move' command acts exactly like [copy], except that it
removes the source nodes after a successful copy. Remember
that the moved nodes are actually different nodes from the
original ones (which may not be obvious when moving nodes
within a single document into locations that do not require
type conversion). So, after the move, the original nodes don't
belong to any document and are automatically destroyed unless
some variable still contains to them.
This command returns a node-list consisting of nodes it
created on the target locations.
See [copy] for more details on how the copies of the moved
nodes are created.
see also: xmove copy xcopy insert xinsert
END
$HELP{'mv'}=$HELP{'move'};
$HELP{'xmove'}=[<<'END'];
usage: xmove [--respective|:r] [--preserve-order|:p] [xpath] [location] [xpath]
aliases: xmv
description:
Like [xcopy], except that 'xmove' removes the source nodes
after a successful copy. Remember that the moved nodes are
actually different nodes from the original ones (which may not
be obvious when moving nodes within a single document into
locations that do not require type conversion). So, after the
move, the original nodes don't belong to any document and are
automatically destroyed unless still contained in some
variable.
This command returns a node-list consisting of all nodes it
created on the target locations.
If '--respective|:r' option is used, then the target node-list
[expression] is evaluated in the context of the source node
being copied.
The '--preserve-order|:p' option can be used to ensure that
the copied nodes are in the same relative order as the
corresponding source nodes. Otherwise, if [location] is
'after' or 'prepend', the relative order of the copied nodes
will be reversed, because source nodes are placed to the
target location one by one.
See [xcopy] for more details on how the copies of the moved
nodes are created.
The following example demonstrates how 'xmove' can be used to
get rid of HTML '<font>' elements while preserving their
content. As an exercise, try to figure out why simple 'foreach
//font { xmove node() replace . }' would not work here.
Example: Get rid of all <font> tags
while //font {
foreach //font {
xmove node() replace .;
}
}
see also: move copy xcopy insert xinsert
END
$HELP{'xmv'}=$HELP{'xmove'};
$HELP{'clone'}=[<<'END'];
usage: $doc := clone [document]
aliases: dup
description:
Create and return a copy of a given [document]. Unless
[switch-to-new-documents] configuration flag is turned off,
the root node of the new document becomes the current node.
Calling this command only makes sense if either
[switch-to-new-documents] is set, or if the result is assigned
to a variable or passed to another XSH2 command using the
'&{...}' syntax, since otherwise the newly created copy of the
document is automatically garbage-collected and destroyed.
see also: open close enc documents
END
$HELP{'dup'}=$HELP{'clone'};
$HELP{'normalize'}=[<<'END'];
usage: normalize [expression]
description:
'normalize' evaluates given [expression] to a node-list and
puts all text nodes in the full depth of the sub-tree
underneath each node in the node-list into a "normal" form
where only structure (e.g., elements, comments, processing
instructions, CDATA sections, and entity references) separates
text nodes, i.e., there are neither adjacent text nodes nor
empty text nodes.
Note, that most XSH2 commands automatically join adjacent text
nodes.
END
$HELP{'strip-whitespace'}=[<<'END'];
usage: strip-whitespace [expression]
aliases: strip_whitespace
description:
'strip-whitespace' removes all leading and trailing whitespace
from given nodes. If applied to an element node, it removes
all leading and trailing child whitespace-only text nodes and
CDATA sections.
END
$HELP{'strip_whitespace'}=$HELP{'strip-whitespace'};
$HELP{'ls'}=[<<'END'];
usage: ls [--fold|:f] [--fold-attrs|:A] [--indent|:i | --no-indent|:I]
[--depth|:d [expression]] [[expression]]
aliases: list
description:
Print XML representation of a given [expression], in
particular, if used with an [xpath], list parts of the
document matching given expression.
If used without an argument, current node is listed to the
depth 1 (see below).
'--depth' or ':d' argument may be used to specify depth of the
XML listing. If negative, the listing depth is unlimited. All
content below the specified depth is replaced with an ellipsis
('...').
'--fold' or ':f' option makes the listing fold elements marked
using the [fold] command are folded, i.e. listed only to the
depth specified in the folding mark.
'--fold-attrs' or ':A' option avoids listing of attributes of
the folded elements (i.e. elements on the lowest level of
listing). Folded attributes are replaced with ellipsis
('...').
'--indent' (':i') and '--no-indent' (':I') may be used to
enforce/suppress indentation, overriding current setting (see
command [indent]).
Unless in [quiet] mode, this command also prints the number of
(top-level) nodes listed.
see also: count fold unfold
END
$HELP{'list'}=$HELP{'ls'};
$HELP{'canonical'}=[<<'END'];
usage: canonical [--comments|:c] [--filter|:f [xpath]] [[expression]]
description:
This commands prints a canonical XML representing nodes
specified by its argument (or current node, if no argument is
given).
'--comments' or ':c' removes comments from the resulting XML.
'--filter' or ':f' can be used to filter the resulting XML so
that it only contains nodes explicitly included in the given
node-set.
For details see "Canonical XML" or "Exclusive XML
Canonicalization" W3C recommendations.
see also: ls
END
$HELP{'count'}=[<<'END'];
usage: count [--quiet|:q] [xpath]
description:
Calculates a given [expression] expression. If the result is a
node-list, print number of nodes in the node-list. If the
[expression] results in a boolean, numeric or literal value,
print the value.
If '--quiet' or ':q' option is used, output is suppressed and
the value is returned.
see also: get
END
$HELP{'change-ns-uri'}=[<<'END'];
usage: change-ns-uri [expression] [[expression]]
description:
This command takes one or two arguments. The first argument is
a new namespace URI and the second, optional, argument is a
namespace prefix. It changes the URI value of a namespace
declaration of the context node to the new value. If no prefix
is given, the change applies to a declaration on the context
node whose prefix equals to the prefix of the context node,
otherwise the change applies to a declaration with the given
prefix.
see also: change-ns-prefix set-ns declare-ns namespaces
END
$HELP{'change-ns-prefix'}=[<<'END'];
usage: change-ns-prefix [expression] [[expression]]
description:
This command takes one or two arguments. The first argument is
a new prefix and the second, optional, argument is an old
namespace prefix. It changes the prefix of a namespace
declaration of the context node to the new value. If no old
prefix is given, the change applies to a declaration on the
context node whose prefix equals to the prefix of the context
node, otherwise the command changes the declaration with the
given old prefix.
The command throws an exception if the new prefix is already
taken by some other declaration in the scope.
see also: change-ns-uri set-ns declare-ns namespaces
END
$HELP{'set-ns'}=[<<'END'];
usage: set-ns [:p|--prefix [expression]] [expression]
description:
This command takes one argument, the namespace URI, possibly
accompanied by a prefix provided in the option '--prefix'
':p'; both these expressions are evaluated as names. The
command changes the namespace of the current element to a
given namespace URI. The current node must be in the scope of
a namespace declaration associating the namespace URI with a
prefix; if prefix option is given, then one of such
declarations must associate the particular given prefix with
the namespace URI. If this condition is not met or the current
node is neither element nor attribute, an error is issued. The
command also changes the prefix of the current element
accordingly.
see also: declare-ns change-ns-uri change-ns-prefix namespaces
END
$HELP{'declare-ns'}=[<<'END'];
usage: declare-ns [expression] [expression]
description:
This command takes one or two arguments: prefix and URI, both
evaluated as names. It creates a namespace declaration of the
form 'xmlns:prefix="URI"' on the current node. The command
produces an error if the prefix is already declared in the
scope of the current node with a different namespace URI.
see also: set-ns change-ns-uri change-ns-prefix namespaces
END
$HELP{'set'}=[<<'END'];
usage: set [xpath] [[xpath]]
description:
This command provides very easy way to create or modify
content of a document. It takes two XPath expressions. The
first one should be a node location path which specifies the
target node, the second is optional and provides new content
for the target node. If a node matches the first XPath
expression, then its content is replaced with the given value.
If no node matches, then XSH2 tries to magically extend the
current document by adding nodes in order to add missing steps
of the location path so as to make the expression match a
node. This node is then populated with a copy of the content
value (either text or, if the content [xpath] results in a
node-list and the target node is an element, nodes).
Example: Try the following on an empty scratch document
$scratch/> ls /
<scratch/>
$scratch/> set scratch/@say "hallo world"
<scratch say="hello world"/>
$scratch/> set scratch/foo[2]/../foo[1]/following-sibling::bar/baz[3] "HALLO"
$scratch/> ls /
<?xml version="1.0" encoding="utf-8"?>
<scratch say="hello world">
<foo/>
<bar>
<baz/>
<baz/>
<baz>HALLO</baz>
</bar>
<foo/>
<scratch/>
Only a limited subset of XPath is currently supported by this
command. Namely, the XPath expression must be a location path
consisting of a /-separated sequence of one or more location
steps and new nodes can only be magically created along the
child, sibling, or attribute axes. The node-test part of the
expression can neither be a wildcard ('*', '@*', 'prefix:*',
...), nor the 'node()' function. If a namespace prefix is
used, then either the namespace must already be declared in
the document or registered with XSH.
Location steps may contain arbitrary predicates (filters),
however, only a limited subset is supported for magically
created nodes. In particular, if a filter predicate of a
location step specifies a position of a node (e.g. with '[4]',
or '[position()>3]', etc), then the parser tries to
automatically create empty siblings nodes until it finally
creates one with for which the predicate is true.
Note, that this command only processes one location step at a
time and always picks the first matching node. So, expressions
like '/root/a/b' are treated as '/root/a[1]/b[1]'. This means
that an expression '/root/a/b' will magically create element
'<b>' in a first matching '<a>' even if some following '<a>'
already contains a '<b>'.
To prevent this, either explicitly state that 'b' must exist
with e.g. '/root/a[b]/b' or make the corresponding element
'<a>' the context node and use a relative location path:
Example:
for /root/a/b set b 'foo'
END
$HELP{'get'}=[<<'END'];
usage: get [expression]
aliases: exp expr
description:
Calculate a given [expression] and return the value.
see also: count
END
$HELP{'exp'}=$HELP{'get'};
$HELP{'expr'}=$HELP{'get'};
$HELP{'perl-code'}=[<<'END'];
Perl-code argument type
description:
A block of Perl code enclosed in braces. All XSH2 variables
are transparently accessible from the Perl code as well.
For more information about embedded Perl code in XSH2,
predefined functions etc., see [Perl_shell].
Example:
xsh> $i={ "foo" };
xsh> perl { echo "$i-bar\n"; } # prints foo-bar
xsh> echo { "$i-bar" } # very much the same as above
END
$HELP{'perl'}=[<<'END'];
usage: perl [perl-code]
description:
Evaluate a given perl expression and return the result.
see also: count
END
$HELP{'remove'}=[<<'END'];
usage: remove [expression]
aliases: rm prune delete del
description:
Unlink all nodes in a given node-list from their respective
documents. Nodes, which are neither attached to a document or
stored in a variable are automatically garbage-collected.
Returns a number of nodes removed.
Example: Get rid of all evil creatures.
xsh> del //creature[@manner='evil']
END
$HELP{'rm'}=$HELP{'remove'};
$HELP{'prune'}=$HELP{'remove'};
$HELP{'delete'}=$HELP{'remove'};
$HELP{'del'}=$HELP{'remove'};
$HELP{'print'}=[<<'END'];
usage: print [--nonl|:n] [--nospace|:s] [--stderr|:e] [expression] [[expression] ...]
aliases: echo
description:
Evaluate given expression(s) and print the results (separated
by a single space character). Expressions not containing any
special characters, such as brackets, quotes, $, or @ are
considered as bare words and evaluate to themselves.
'--nonl' or ':n' can be used to avoid printing a trailing
new-line.
'--nospace' or ':s' suppresses printing additional spaces
between individual arguments.
'--stderr' or ':e' causes the command to print on standard
error output.
Example:
print foo bar; # prints "foo bar"
print "foo bar"; # prints "foo bar"
END
$HELP{'echo'}=$HELP{'print'};
$HELP{'sort'}=[<<'END'];
usage: $result := sort [ --key|:k [expression] ]
--compare|:c [perl-code] [expression]
$result := sort [ --key|:k [expression] ]
[ --numeric|:n ] [ --descending|:d ] [ --locale|:l] [expression]
description:
This command sorts a given node-list, returning a node-list
ordered according to a given key and ordering function.
'--key|:k' followed by an expression specifies the key to be
computed for each member of the node-list and the result used
as the sorting key. If omitted, keys are created by converting
the nodes to string as if XPath expression 'string(.)' was
used.
'--numeric|:n' specifies, that keys should be compared by
their numerical values (the default is string comparison).
'--descending|:d' specifies, that the result should be ordered
in descending order (default is ascending).
'--locale|:l' forces using current locale settings for string
comparison (default is no locale).
'--compare' argument followed by a [perl-code] allows to
define a custom comparison method in a similar way to Perl
'sort' command. The keys to be compared are passed to the code
in variables '$a' and '$b'. The code is supposed to return 1
if the key in '$a' is greater than '$b', 0 if the keys are
equal and '-1' if '$a' is less than '$b', depending on how the
corresponding elements are to be ordered. It is a run-time
error to use '--compare' together with either '--numeric' or
'--descending'.
Example: Case-insensitive sort of a given node-list
$ordered := sort --key xsh:lc(.) $unordered;
Example: Reorder creature elements by name attribute in ascending order
using Czech locale settings
perl {
# setup locale collating function
# Note, that the collating function must be UTF8 aware.
use POSIX qw(locale_h);
setlocale(LC_COLLATE,'cs_CZ.UTF-8');
};
xmove &{ sort :k@name :l * } into /middle-earth[1]/creatures;
Example: Sort a node-list by a pre-computed score (Perl-based sort)
$results := sort --numeric --descending --key { $scores{literal('@name')} } $players;
END
$HELP{'map'}=[<<'END'];
usage: map [expression] [expression]
description:
NOTE: THE SEMANTICS OF COMMAND HAS CHANGED IN 2.1.0
This command provides an easy way to transform node's data
(content) using arbitrary expression. It takes two arguments:
a mapping expression and a node-list.
First the second argument is evaluated to a node-list. For
each of the nodes, the mapping expression is evaluated and the
result is used to replace the original content of the node.
The node is made the context node for the time of evaluation
of the mapping expression. Moreover, if the expression is a
Perl code, it gets the original text content in the variable
'$_'.
Note that if the processed node is an element than the mapping
expression may even produce nodes which are then copied into
the element discarding any previous content of the element.
If the mapping expression returns an undefined value for a
node, then its content is kept untouched.
'--in-place' (':i') flag: if the expression is a Perl code,
then it is sometimes convenient to change the value in place.
In that case use this flag to indicate that the result should
to be taken from the '$_' variable rather than from the value
of the expression itself. Without this flag, '$_' is
read-only.
'--reverse' (':r') flag instruct the map to process the
nodelist in reversed order.
Example: Capitalizes all hobbit names
map { ucfirst($_) } //hobbit/@name;
Example: Changes Goblins to Orcs in all hobbit tales (\b matches word
boundary).
map :i { s/\bgoblin\b/orc/gi } //hobbit/tale/text();
Example: Recompute column sums in the last row of row-oriented table
map sum(/table/row[position()<last()]/
cell[count(xsh:current()/preceding-sibling::cell)+1])
/table/row[last()]/cell;
Example: The following commands do all about the same:
wrap --inner Z //*;
map --reverse xsh:parse(concat("<Z>",xsh:serialize(node()),"</Z>")) //*;
map xsh:parse(concat("<Z>",xsh:serialize(node()),"</Z>")) { reverse xpath('//*') };
Note that in the last example we use ':r' (or Perl 'reverse'
function) to reverse the node list order so that child nodes
get processed before their parents. Otherwise, the child nodes
would be replaced by parent's new content before the
processing could reach them.
see also: rename
END
$HELP{'rename'}=[<<'END'];
usage: rename [nodename] [expression]
description:
NOTE: THE SEMANTICS OF COMMAND HAS CHANGED IN 2.1.0
This command is very similar to the [map] command, except that
it operates on nodes' names rather than their content. It
changes name of every element, attribute or
processing-instruction contained in the node-list specified in
the second argument [expression], according to the value of
the [nodename] expression, which is evaluated in the context
of each node in turn.
If the [nodename] is a Perl expression, then the name of the
node is also stored into Perl's '$_' variable prior to
evaluation.
The flag '--in-place' (':i') can be used to indicate that the
new name should be collected from the '$_' variable rather
than from the result of the expression itself.
The '--namespace' (':n') argument may be used to provide
namespace for the renamed nodes.
'--reverse' (':r') flag instruct the map to process the
nodelist in reversed order.
Note: if the expression [nodename] returns an undefined value
for a particular node, the node's original name and namespace
are preserved.
Example: Renames all Hobbits to Halflings
xsh> rename halfling //hobbit
Example: Make all elements and attributes uppercase (yack!)
xsh> rename { uc } (//*|//@*)
Example: Substitute dashes with underscores in all node names
xsh> rename :i { s/-/_/g } (//*|//@*)
Example: Make all elements start with the name of their parents
xsh> rename concat(local-name(parent::*),'.',local-name(.)) //*[parent::*]
see also: map
END
$HELP{'hash'}=[<<'END'];
usage: $hash := hash [expression] [expression]
description:
This command takes two arguments: an expression computing a
key from a given node (1st argument) and a node-set (2nd
argument). For each node in the node-set, the key value is
computed and the node is stored under the given key in the
resulting hash. For a given key, the value stored in the hash
table is a node-list consisting of all nodes for which the 1st
expression evaluated to an object string-wise equal to the
key. It is therefore possible to index more than one node
under the same key.
The XPath function 'xsh:lookup(varname,key)' can be used to
retrieve values from hashes in XPath expressions.
Example: Index books by author
my $books_by_author := hash concat(author/firstname," ",author/surname) //book;
Example: Lookup books by Jack London.
ls { $books_by_author->{'Jack London'} };
ls xsh:lookup('books_by_author','Jack London');
see also: xsh:lookup
END
$HELP{'close'}=[<<'END'];
usage: close [[document]]
description:
Close a given [document] (or, if called with no argument, the
current document) by trying to remove all references from XSH2
variables to nodes belonging to the document. If no references
to the document are left, the garbage-collector destroys the
DOM tree and frees the memory it occupied for later reuse
(depending on architecture, this may or may not give the
allocated memory back to the system).
END
$HELP{'index'}=[<<'END'];
usage: index [[document]]
description:
This command makes 'libxml2' library to remember
document-order position of every element node in the
[document]. Such indexation makes XPath queries considerably
faster on large documents (with thousands of nodes). The
command should only be used on documents which don't change;
modifying an indexed document might possibly lead to
non-conformant behavior of later XPath queries on the
document.
END
$HELP{'open'}=[<<'END'];
usage: $doc := open [--format|:F html|xml|docbook]
[--file|:f | --pipe|:p | --string|:s]
[--switch-to|:w | --no-switch-to|:W]
[--validate|:v | --no-validate|:V]
[--recover|:r | --no-recover|:R]
[--expand-entities|:e | --no-expand-entities|:E]
[--xinclude|:x | --no-xinclude|:X]
[--keep-blanks|:b | --no-keep-blanks|:B]
[--pedantic|:n | --no-pedantic|:N]
[--load-ext-dtd|:d | --no-load-ext-dtd|:D]
[--complete-attributes|:a | --no-complete-attributes|:A]
[expression]
description:
Parse a XML, HTML or SGML DOCBOOK document from a file or URL,
command output or string and return a node-set consisting of
the root of the resulting DOM tree.
'--format' (':F') option may be used to specify file format.
Possible values are 'xml' (default), 'html', and 'docbook'.
Note, however, that the support for parsing 'DocBook' SGML
files has been deprecated in recent 'libxml2' versions.
'--file' (':f') instructs the parser to consider a given
[expression] as a file name or URL.
'--pipe' (':p') instructs the parser to consider a given
[expression] as a system command and parse its output.
'--string' (':s') instructs the parser to consider a given
[expression] as a string of XML or HTML to parse.
'--switch-to' (':w') and '--no-switch-to' (':W') control
whether the new document's root should become current node.
These option override current global setting of
[switch-to-new-documents].
'--validate' (':v') and '--no-validate' (':V') turn on/off
DTD-validation of the parsed document. These option override
current global setting of [validation].
'--recover' (':r') and '--no-recover' (':R') turn on/off
parser's ability to recover from non-fatal errors. These
option override current global setting of [recovering].
'--expand-entities' (':e') and '--no-expand-entities' (':E')
turn on/off entity expansion, overriding current global
setting of [parser-expands-entities].
'--xinclude' (':x') and '--no-xinclude' (':X') turn on/off
XInclude processing, overriding current global settings of
[parser-expands-xinclude].
'--keep-blanks' (':b') and '--no-keep-blanks' (':B') control
whether the parser should preserve so called ignorable
whitespace. These option override current global setting of
[keep-blanks].
'--pedantic' (':n') and '--no-pedantic' (':N') turn on/off
pedantic parser flag.
'--load-ext-dtd' (':d') and '--no-load-ext-dtd' (':D') control
whether the external DTD subset should be loaded with the
document. These option override current global setting of
[load-ext-dtd].
'--complete-attributes' (':a') and '--no-complete-attributes'
(':A') turn on/off parse-time default attribute completion
based on default values specified in the DTD. These option
override current global setting of
[parser-completes-attributes].
Example:
$scratch/> $x := open mydoc.xml # open an XML document
# open a HTML document from the Internet
$h:=open --format html "http://www.google.com/?q=xsh"
# quote file name if it contains whitespace
$y := open "document with a long name with spaces.xml"
# use --format html or --format docbook to load these types
$z := open --format html index.htm
# use --pipe flag to read output of a command
$z := open --format html --pipe 'wget -O - xsh.sourceforge.net/index.html'
# use document variable to restrict XPath search to a
# given document
ls $z//chapter/title
END
$HELP{'create'}=[<<'END'];
usage: $doc := create [nodename]|[expression]
aliases: new
description:
Returns a new document object. The argument must evaluate
either to a valid element name (possibly followed by some
attribute declarations) to be used for the document element,
or to a well-formed XML string.
Unless [switch-to-new-documents] option is turned off, this
command also changes current node to the new document.
Example:
$scratch/> $t1 := create root
$t1> ls $t1
<?xml version="1.0" encoding="utf-8"?>
<root/>
$t1> $t2 := create "root id='r1'"
$t2> ls $t2
<?xml version="1.0" encoding="utf-8"?>
<root id="r1"/>
$t2> create "<root id='r0'>Just a <b>test</b></root>"
/> ls /
<?xml version="1.0" encoding="utf-8"?>
<root id='r0'>Just a <b>test</b></root>
see also: open clone
END
$HELP{'new'}=$HELP{'create'};
$HELP{'save'}=[<<'END'];
usage: save [--format|:F html|xml] [--xinclude|:x]
[--file|:f [filename] |
--pipe|:p [filename] |
--string|:s |
--print|:r ]
[--subtree|:S]
[--indent|:i | --no-indent|:I]
[--skip-dtd|:d | --no-skip-dtd|:D]
[--skip-empty-tags|:t | --no-skip-empty-tags|:T]
[--skip-xmldecl|:x]
[--encoding|:e [encoding]]
[document]
description:
This takes a given [document], serializes it to XML or HTML
and either saves the result to its original file or another
file (default), pipes it to an external command, prints it on
standard output, or simply returns it. Without arguments it
simply saves current document to its original file.
'--file|:f' option may be used to specify an output file-name.
By default, the original document's file-name is used.
'--pipe|:p' option specifies, that the output should be piped
to an external command specified as the option's argument.
'--print|:r' option specifies, that the output should be
printed on standard output.
'--string|:s' option specifies, that the output should be
returned by the command as a string. In this case, the result
is always in UTF8, regardless on which encoding is specified
in the document or using '--encoding' option.
The above four options are mutually exclusive.
'--format' option may be used to specify the output format.
It's argument should be either 'xml', 'html' or an expression
evaluating to one of these. If not specified, XML output is
assumed. Note, that a document should be saved as HTML only if
it actually is a HTML document, otherwise the result would be
an invalid XML instance. Note also, that the optional encoding
parameter only forces character conversion; it is up to the
user to declare the document encoding in the appropriate HTML
<META> tag, if needed.
'--xinclude' automatically implies XML format and can be used
to force XSH2 to save all already expanded XInclude sections
back to their original files while replacing them with
<xi:include> tags in the main XML file. Moreover, all material
included within <include> elements from the
http://www.w3.org/2001/XInclude namespace is saved to separate
files too according to the 'href' attribute, leaving only
empty <include> element in the root file. This feature may be
used to split the document to a new set of XInclude fragments.
If the '--subtree' (':S') flag is used, only the subtree of
the specified node is saved instead of the complete document
(this flag cannot be used with '--html' format).
'--indent' (':i') and '--no-indent' (':I') may be used to
enforce/suppress indentation, overriding current global
setting of [indent].
'--skip-dtd' (':d') and '--no-skip-dtd' (':D') may be used to
enforce/suppress skipping DTD declaration and internal subset
on output, overriding current global setting of [skip-dtd].
'--empty-tags' (':t') and '--no-empty-tags' (':T') may be used
to override current global setting of [empty-tags].
'--no-empty-tags' instructs XSH2 to serialize elements with no
child nodes as start-tag/end-tag pair '<element></element>'
instead of using a short empty-tag form '<element/>'.
'--skip-xmldecl' (':x') instructs XSH2 to omit the XML
declaration from the saved document. Note however, that XML
declaration is obligatory for XML documents. It usually looks
like '<?xml version="1.0" ...?>'.
'--backup' (':b') and '--no-backup' (':B') can be used to
enforce/suppress creation of a backup file if target file
already exists. Using these options overrides current global
setting of [backups].
'--encoding' followed by a [encoding] instructs XSH2 to save
the document in the specified encoding. In case of XML output,
the <?xml?> declaration is automatically changed accordingly.
Example: Use save to preview current HTML document in Lynx
save --format html --pipe 'lynx -stdin'
see also: open close enc documents
END
$HELP{'set-dtd'}=[<<'END'];
usage: set-dtd [--internal] [--name|:n [expression]]
[--public|:p [expression]]
[--system|:s [expression]]
[[document]]
aliases: set_dtd
description:
Set external (default) or internal DTD for a given document.
If no [document] is given, the current document is used. At
least one of '--public' and '--system' options should be used
to specify the PUBLIC and SYSTEM identifiers of the DTD. If
'--name' parameter is not provided, name of the document root
element is used as DTD name.
see also: dtd validate
END
$HELP{'set_dtd'}=$HELP{'set-dtd'};
$HELP{'dtd'}=[<<'END'];
usage: dtd [[document]]
description:
Print external or internal DTD for a given document. If used
without arguments prints DTD of the current document.
see also: set-dtd validate
END
$HELP{'set-enc'}=[<<'END'];
usage: set-enc [encoding] [[document]]
description:
Changes character encoding of a given document. If no
[document] is given, the command applies to the current
document. This has two effects: changing the XMLDecl encoding
declaration in the document prolog to display the new encoding
and making all future [save] operations on the document
default to the given charset.
Example:
xsh> ls
<?xml version="1.0" encoding="iso-8859-1"?>
<foo>...</foo>
xsh> set-enc "utf-8"
xsh> ls
<?xml version="1.0" encoding="utf-8"?>
<foo>...</foo>
xsh> save # saves the file in UTF-8 encoding
see also: enc doc-info
END
$HELP{'set-standalone'}=[<<'END'];
usage: set-standalone [expression] [[document]]
description:
Changes the value of 'standalone' declaration in the XMLDecl
prolog of a document. The [expression] should evaluate to
either 1 or 0 or ''yes'' or ''no''. The result of applying the
command on other values is not specified. If no [document] is
given, the command applies to the current document.
see also: doc-info
END
$HELP{'enc'}=[<<'END'];
usage: enc [[document]]
description:
Print the original document encoding string. If no [document]
is given, the current document is used.
see also: set-enc
END
$HELP{'validate'}=[<<'END'];
usage: validate [--yesno|:q] [[document]]
validate [--yesno|:q] [--dtd|:D | --relaxng|:R | --schema|:S] --file|:f [filename]] [[document]]
validate [--yesno|:q] [--dtd|:D | --relaxng|:R | --schema|:S] --string|:s [expression]] [[document]]
validate [--yesno|:q] [--dtd|:D | --relaxng|:R | --schema|:S] --doc|:d [document]] [[document]]
validate [--yesno|:q] [--dtd|:d] --public|:p [expression] [--file|:f [expression]] [[document]]
description:
This command validates the current document or a document
specified in the argument against a DTD, RelaxNG or XSD
schema. If '--yesno' or ':q' is specified, only prints 'yes'
and returns 1 if the document validates or 'no' and returns 0
if it does not. Without '--yesno', it throws an exception with
a complete validation error message if the document doesn't
validate.
'--dtd' or ':D' forces DTD validation (default).
'--relaxng' or ':R' forces RelaxNG validation. Only XML
RelaxNG grammars are supported.
'--schema' or ':S' forces W3C XML Schema validation (XSD).
Support for schema validation may still be incomplete (see
libxml2 home page for more details).
A DTD subset can be specified by its PUBLIC identifier (with
'--public'), by its SYSTEM identifier (with '--file'), or as a
string (with '--string'). If none of these options is used,
validation is performed against the internal or external DTD
subset of the document being validated.
RelaxNG grammars and XML Schemas can either be specified
either as a filename or url (with '--file'), as a string
containing (with '--string'), or as a document currently open
in XSH2 (with '--doc').
Example:
$mydoc := open "test.xml"
# in all examples below, mydoc can be omitted
validate --yesno $mydoc; # validate against the document's DOCTYPE
validate --public "-//OASIS//DTD DocBook XML V4.1.2//EN" $mydoc
validate --file "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" $mydoc
Example:
validate --relaxng --file "test.rng" $mydoc
validate --relaxng --string $relaxschema $mydoc
$rng := open "test.rng"
validate --relaxng --doc $rng $mydoc
Example:
validate --schema --file "test.xsd" $mydoc
validate --schema --string $xsdschema $mydoc
$xsd := open "test.xsd"
validate --schema --doc $xsd $mydoc
see also: dtd
END
$HELP{'exit'}=[<<'END'];
usage: exit [[expression]]
aliases: quit
description:
Exit xsh, optionally with an exit-code resulting from
evaluation of a given [expression].
WARNING: No files are saved on exit.
END
$HELP{'quit'}=$HELP{'exit'};
$HELP{'process-xinclude'}=[<<'END'];
usage: process-xinclude [[document]]
aliases: process_xinclude process-xincludes process_xincludes xinclude xincludes load_xincludes load-xincludes load_xinclude load-xinclude
description:
Replace any xinclude tags in a given [document] with the
corresponding content. See http://www.w3.org/TR/xinclude/ to
find out more about XInclude technology.
see also: parser-expands-xinclude
END
$HELP{'process_xinclude'}=$HELP{'process-xinclude'};
$HELP{'process-xincludes'}=$HELP{'process-xinclude'};
$HELP{'process_xincludes'}=$HELP{'process-xinclude'};
$HELP{'xinclude'}=$HELP{'process-xinclude'};
$HELP{'xincludes'}=$HELP{'process-xinclude'};
$HELP{'load_xincludes'}=$HELP{'process-xinclude'};
$HELP{'load-xincludes'}=$HELP{'process-xinclude'};
$HELP{'load_xinclude'}=$HELP{'process-xinclude'};
$HELP{'load-xinclude'}=$HELP{'process-xinclude'};
$HELP{'cd'}=[<<'END'];
usage: cd [[expression]]
aliases: chxpath
description:
Evaluate given [expression] to a node-list and change current
context node to the first node in it.
END
$HELP{'chxpath'}=$HELP{'cd'};
$HELP{'pwd'}=[<<'END'];
usage: pwd [--id|:i]
description:
Print XPath leading to the current context node (equivalent to
'locate .').
If flag '--id' (':i') is used then ID-based shortcut is
allowed in the resulting location path. That means that if the
current node or some of its ancestors has an ID attribute
(either 'xml:id' or one specified in a DTD) then the
corresponding segment of the canonical location path is
replaced by the 'id()' function which jumps directly to an
element based on its ID.
see also: locate xsh:path
END
$HELP{'locate'}=[<<'END'];
usage: locate [--id|:i] [xpath]
description:
Print canonical XPaths leading to nodes matched by a given
[xpath].
If flag '--id' (':i') is used then ID-based shortcuts are
allowed in the resulting location paths. That means that if
the node or some of its ancestors has an ID attribute (either
'xml:id' or one specified in a DTD) then the corresponding
segment of the canonical location path is replaced by the
'id()' function which jumps directly to an element based on
its ID.
see also: pwd
END
$HELP{'xupdate'}=[<<'END'];
usage: xupdate [document] [[document]]
description:
Modify the current document or the document specified by the
second [document] argument according to XUpdate commands of
the first [document] argument. XUpdate, or more specifically
the XML Update Language, aims to be a language for updating
XML documents.
XUpdate language is described in XUpdate Working Draft at
http://xmldb-org.sourceforge.net/xupdate/xupdate-wd.html.
XUpdate output can be generated for example by Python xmldiff
utility from http://www.logilab.org/projects/xmldiff/.
END
$HELP{'verbose'}=[<<'END'];
usage: verbose
description:
Turn on verbose messages (default).
This is equivalent to setting '$QUIET' variable to 0.
see also: quiet
END
$HELP{'test-mode'}=[<<'END'];
usage: test-mode
aliases: test_mode
description:
Switch into a mode in which no commands are actually executed
and only command syntax is checked.
This is equivalent to setting '$TEST_MODE' variable to 1.
see also: run-mode
END
$HELP{'test_mode'}=$HELP{'test-mode'};
$HELP{'run-mode'}=[<<'END'];
usage: run-mode
aliases: run_mode
description:
Switch from the [test-mode] back to the normal execution mode.
This is equivalent to setting '$TEST_MODE' variable to 0.
see also: test-mode
END
$HELP{'run_mode'}=$HELP{'run-mode'};
$HELP{'debug'}=[<<'END'];
usage: debug
description:
Turn on debugging messages.
This is equivalent to setting '$DEBUG' variable to 1.
see also: nodebug
END
$HELP{'nodebug'}=[<<'END'];
usage: nodebug
description:
Turn off debugging messages.
This is equivalent to setting '$DEBUG' variable to 0.
see also: debug
END
$HELP{'version'}=[<<'END'];
usage: version
description:
Prints program version plus version numbers of the most
important libraries used.
END
$HELP{'validation'}=[<<'END'];
usage: validation [expression]
description:
Turn on validation during the parse process if the
[expression] is non-zero or off otherwise. Defaults to off.
This command is equivalent to setting the '$VALIDATION'
variable.
END
$HELP{'recovering'}=[<<'END'];
usage: recovering [expression]
description:
If the [expression] evaluates to non-zero value, turn on the
recovering parser mode on; turn it off otherwise. Defaults to
off.
Note, that the in the recovering mode, validation is not
performed by the parser even if the validation flag is on.
The recover mode helps to efficiently recover documents that
are almost well-formed. This for example includes documents
without a close tag for the document element (or any other
element inside the document).
This command is equivalent to setting the '$RECOVERING'
variable.
END
$HELP{'parser-expands-entities'}=[<<'END'];
usage: parser-expands-entities [expression]
aliases: parser_expands_entities
description:
If the [expression] is non-zero enable the entity expansion
during the parse process; disable it otherwise. If entity
expansion is disabled, any external entity references in
parsed documents are preserved as references. By default,
entity expansion is enabled.
This command is equivalent to setting the
'$PARSER_EXPANDS_ENTITIES' variable.
END
$HELP{'parser_expands_entities'}=$HELP{'parser-expands-entities'};
$HELP{'keep-blanks'}=[<<'END'];
usage: keep-blanks [expression]
aliases: keep_blanks
description:
Allows you to turn on/off preserving the parser's default
behavior of preserving all whitespace in the document. Setting
this option to 0, instructs the XML parser to ignore
whitespace occurring between adjacent element nodes, so that
no extra text nodes are created for it.
This command is equivalent to setting the '$KEEP_BLANKS'
variable.
END
$HELP{'keep_blanks'}=$HELP{'keep-blanks'};
$HELP{'pedantic-parser'}=[<<'END'];
usage: pedantic-parser [expression]
aliases: pedantic_parser
description:
If you wish, you can make the XML parser little more pedantic
by passing a non-zero [expression] to this command.
This command is equivalent to setting the '$PEDANTIC_PARSER'
variable.
END
$HELP{'pedantic_parser'}=$HELP{'pedantic-parser'};
$HELP{'parser-completes-attributes'}=[<<'END'];
usage: parser-completes-attributes [expression]
aliases: complete_attributes complete-attributes parser_completes_attributes
description:
If the expression is non-zero, the command makes XML parser
add missing attributes with default values as specified in a
DTD. By default, this option is enabled.
This command is equivalent to setting the
'$PARSER_COMPLETES_ATTRIBUTES' variable.
END
$HELP{'complete_attributes'}=$HELP{'parser-completes-attributes'};
$HELP{'complete-attributes'}=$HELP{'parser-completes-attributes'};
$HELP{'parser_completes_attributes'}=$HELP{'parser-completes-attributes'};
$HELP{'indent'}=[<<'END'];
usage: indent [expression]
description:
If the value of [expression] is 1, saved and listed XML will
be formatted using some (hopefully) ignorable whitespace. If
the value is 2 (or higher), XSH2 will act as in case of 1,
plus it will add a leading and a trailing linebreak to each
text node.
Note, that since the underlying C library (libxml2) uses a
hard-coded indentation of 2 space characters per indentation
level, the amount of whitespace used for indentation can not
be altered at runtime.
This command is equivalent to setting the '$INDENT' variable.
END
$HELP{'empty-tags'}=[<<'END'];
usage: empty-tags [expression]
aliases: empty_tags
description:
If the value of [expression] is 1 (non-zero), empty tags are
serialized as a start-tag/end-tag pair ('<foo></foo>'). This
option affects both [ls] and [save] and possibly other
commands. Otherwise, they are compacted into a short-tag form
('<foo/>'). Default value is '0'.
This command is equivalent to setting the '$EMPTY_TAGS'
variable.
END
$HELP{'empty_tags'}=$HELP{'empty-tags'};
$HELP{'skip-dtd'}=[<<'END'];
usage: skip-dtd [expression]
aliases: skip_dtd
description:
If the value of [expression] is 1 (non-zero), DTD DOCTYPE
declaration is omitted from any further serializations of XML
documents (including [ls] and [save]). Default value is '0'.
This command is equivalent to setting the '$SKIP_DTD'
variable.
END
$HELP{'skip_dtd'}=$HELP{'skip-dtd'};
$HELP{'parser-expands-xinclude'}=[<<'END'];
usage: parser-expands-xinclude [expression]
aliases: parser_expands_xinclude
description:
If the [expression] is non-zero, the parser is allowed to
expand XInclude tags immediately while parsing the document.
This command is equivalent to setting the
'$PARSER_EXPANDS_XINCLUDE' variable.
see also: process-xinclude
END
$HELP{'parser_expands_xinclude'}=$HELP{'parser-expands-xinclude'};
$HELP{'load-ext-dtd'}=[<<'END'];
usage: load-ext-dtd [expression]
aliases: load_ext_dtd
description:
Non-zero [expression] instructs the XML parser to load
external DTD subsets declared in XML documents. This option is
enabled by default.
This command is equivalent to setting the '$LOAD_EXT_DTD'
variable.
END
$HELP{'load_ext_dtd'}=$HELP{'load-ext-dtd'};
$HELP{'encoding'}=[<<'END'];
usage: encoding [encoding]
description:
Set the default character encoding used for standard (e.g.
terminal) output. This doesn't influence the encoding used for
saving XML documents.
This command is equivalent to setting the '$ENCODING'
variable.
see also: query-encoding
END
$HELP{'query-encoding'}=[<<'END'];
usage: query-encoding [encoding]
aliases: query_encoding
description:
Set the default query character encoding, i.e. encoding used
when taking input from XSH2 prompt or standard input.
This command is equivalent to setting the '$QUERY_ENCODING'
variable.
see also: encoding
END
$HELP{'query_encoding'}=$HELP{'query-encoding'};
$HELP{'quiet'}=[<<'END'];
usage: quiet
description:
Turn off verbose messages.
This command is equivalent to setting the '$QUIET' variable.
see also: verbose
END
$HELP{'switch-to-new-documents'}=[<<'END'];
usage: switch-to-new-documents [expression]
aliases: switch_to_new_documents
description:
If non-zero, XSH2 changes current node to the document node of
a newly open/created files every time a new document is opened
or created with [open] or [create]. Default value for this
option is 1.
This command is equivalent to setting the
'$SWITCH_TO_NEW_DOCUMENTS' variable.
END
$HELP{'switch_to_new_documents'}=$HELP{'switch-to-new-documents'};
$HELP{'backups'}=[<<'END'];
usage: backups
description:
Enable creating backup files on save (default).
This command is equivalent to setting the '$BACKUPS' variable
to 1.
see also: nobackups
END
$HELP{'nobackups'}=[<<'END'];
usage: nobackups
description:
Disable creating backup files on save.
This command is equivalent to setting the '$BACKUPS' variable
to 0.
see also: nobackups
END
$HELP{'fold'}=[<<'END'];
usage: fold [--depth|:d [expression]] [[expression]]
description:
This feature is still EXPERIMENTAL and may change in the
future! Fold command may be used to mark elements with a
'xsh:fold' attribute from the
'http://xsh.sourceforge.net/xsh/' namespace. When listing the
DOM tree using '[ls] --fold [xpath]', elements marked in this
way are folded to a given depth (default is 0 = fold
immediately).
The option '--depth' (':d') may be used to specify the depth
at which subtrees of given elements are to be folded.
If called without arguments, the command applies to the
current element, otherwise the [expression] is evaluated to
the node-list and folding is applied to all elements within
this node-list.
Example:
xsh> fold --depth 1 //chapter
xsh> ls --fold //chapter[1]
<chapter id="intro" xsh:fold="1">
<title>...</title>
<para>...</para>
<para>...</para>
</chapter>
see also: unfold ls
END
$HELP{'unfold'}=[<<'END'];
usage: unfold [expression]
description:
This feature is still EXPERIMENTAL!
Unfold command removes 'xsh:fold' attributes from all given
elements. Such attributes are usually created by previous
usage of [fold]. Be aware, that 'xmlns:xsh' namespace
declaration may still be present in the document even when all
elements are unfolded.
see also: fold ls
END
$HELP{'redo'}=[<<'END'];
usage: redo [[expression]]
description:
'redo' restarts a loop block without evaluating the
conditional again. The optional [expression] argument may
evaluate to a positive integer number that indicates which
level of the nested loops should be restarted. If omitted, it
defaults to 1, i.e. the innermost loop.
Using this command outside a loop causes an immediate run-time
error.
Example: Restart a higher level loop from an inner one
while ($i<100) {
# ...
foreach //para {
# some code
if $param {
redo; # redo foreach loop
} else {
redo 2; # redo while loop
}
}
}
see also: foreach while iterate next last
END
$HELP{'next'}=[<<'END'];
usage: next [[expression]]
description:
'next' is like the continue statement in C; it starts the next
iteration of an enclosing loop. The command may be used with
an optional argument evaluating to a positive integer number
indicating which level of the nested loops should be
restarted. If the argument is omitted, it defaults to 1, i.e.
the innermost loop.
Using this command outside a loop causes an immediate run-time
error.
see also: foreach while iterate redo last prev
END
$HELP{'prev'}=[<<'END'];
usage: prev [[expression]]
description:
This command is only allowed inside an 'iterate' loop. It
returns the iteration one step back, to the previous node on
the iterated axis. The optional [expression] argument may be
used to indicate to which level of nested loops the command
applies to (default is 1).
see also: iterate redo last next
END
$HELP{'last'}=[<<'END'];
usage: last [[expression]]
description:
The 'last' command is like the break statement in C (as used
in loops); it immediately exits an enclosing loop. The
optional [expression] argument may evaluate to a positive
integer number that indicates which level of the nested loops
to quit. If this argument is omitted, it defaults to 1, i.e.
the innermost loop.
Using this command outside a loop causes an immediate run-time
error.
see also: foreach while iterate next last
END
$HELP{'return'}=[<<'END'];
usage: return [[expression]]
description:
This command immediately stops the execution of a procedure it
occurs in and returns the execution to the place of the script
from which the subroutine was called. Optional argument may be
used as a return value for the subroutine call.
Using this command outside a subroutine causes an immediate
run-time error.
see also: def call
END
$HELP{'throw'}=[<<'END'];
usage: throw [expression]
description:
This command throws and exception containing error message
given by the obligatory [expression] argument. If the
exception is not handled by some surrounding [try] block, the
execution is stopped immediately and the error message is
printed.
see also: try
END
$HELP{'catalog'}=[<<'END'];
usage: catalog [filename]
description:
Make use of a given XML file as a catalog during all parsing
processes. Using a catalog may significantly speed up parsing
processes if many external resources are loaded into the
parsed documents (such as DTDs or XIncludes).
END
$HELP{'iterate'}=[<<'END'];
usage: iterate [xpath] [block]
description:
Iterate works very much like a [foreach] loop with the same
[xpath] expression, except that it evaluates the [block] as
soon as a new node matching a given [xpath] is found. As a
limitation, an [xpath] expression used with 'iterate' may
consist of one XPath step only, i.e. it may not contain an
XPath step separator '/'.
A possible benefit of using 'iterate' instead of [foreach] is
some efficiency when iterating over huge node-sets. Since
'iterate' doesn't compute the resulting node-set in advance,
it doesn't have to 1) allocate extra memory for it and 2)
(more importantly) doesn't have to sort the node-list in the
document order (which tends to be slow on large node-sets,
unless [index] is used). On the other hand, 'iterate' suffers
from a considerable speed penalty since it isn't implemented
in C (unlike libxml2's XPath engine).
Author's experience shows that, unless [index] is used,
'iterate' beats [foreach] in speed on large node-lists (>=1500
nodes, but your milage may vary) while [foreach] wins on
smaller node-lists.
The following two examples give equivalent results. However,
the one using 'iterate' may be faster if the number of nodes
being counted is huge and document order isn't indexed.
Example: Count inhabitants of the kingdom of Rohan in productive age
cd rohan/inhabitants;
iterate child::*[@age>=18 and @age<60] { perl $productive++ };
echo "$productive inhabitants in productive age";
Example: Using XPath
$productive=count(rohan/inhabitants/*[@age>=18 and @age<60]);
echo "$productive inhabitants in productive age";
Hint: use e.g. '| time cut' pipe-line redirection to benchmark
a XSH2 command on a UNIX system.
see also: foreach index next prev last
END
$HELP{'register-namespace'}=[<<'END'];
usage: register-namespace [expression] [expression]
aliases: regns
description:
Registers the first argument as a prefix for the namespace
given in the second argument. The prefix can later be used in
XPath expressions.
END
$HELP{'regns'}=$HELP{'register-namespace'};
$HELP{'unregister-namespace'}=[<<'END'];
usage: unregister-namespace [expression]
aliases: unregns
description:
Unregisters given namespace prefix previously registered using
[register-namespace]. The prefix can no longer be used in
XPath expressions unless declared within the current scope of
the queried document.
END
$HELP{'unregns'}=$HELP{'unregister-namespace'};
$HELP{'register-xhtml-namespace'}=[<<'END'];
usage: register-xhtml-namespace [expression]
aliases: regns-xhtml
description:
Registers a prefix for the XHTML namespace
'http://www.w3.org/1999/xhtml'. The prefix can later be used
in XPath expressions.
END
$HELP{'regns-xhtml'}=$HELP{'register-xhtml-namespace'};
$HELP{'register-xsh-namespace'}=[<<'END'];
usage: register-xsh-namespace [expression]
aliases: regns-xsh
description:
Registers a new prefix for the XSH2 namespace
'http://xsh.sourceforge.net/xsh/'. The prefix can later be
used in XPath expressions. Note, that XSH2 namespace is by
default registered with the prefix 'xsh'. This command is
thus, in general, useful only when some document uses 'xsh'
prefix for a different namespace or if you want a shorter
prefix.
END
$HELP{'regns-xsh'}=$HELP{'register-xsh-namespace'};
$HELP{'register-function'}=[<<'END'];
usage: register-function [expression] [perl-code]
aliases: function regfunc
description:
EXPERIMENTAL!
Registers a given perl code as a new XPath extension function
under a name provided in the first argument. XML::LibXML DOM
API as well as all Perl functions pre-defined in the
XML::XSH2::Map namespace may be used in the perl code for
object processing. If the name contains a colon, then the
first part before the colon must be a registered namespace
prefix (see [register-namespace]) and the function is
registered within the corresponding namespace.
END
$HELP{'function'}=$HELP{'register-function'};
$HELP{'regfunc'}=$HELP{'register-function'};
$HELP{'unregister-function'}=[<<'END'];
usage: unregister-function [expression]
aliases: unregfunc
description:
EXPERIMENTAL! Unregister XPath extension function of a given
name previously registered using [register-function].
END
$HELP{'unregfunc'}=$HELP{'unregister-function'};
$HELP{'stream'}=[<<'END'];
usage: stream [ --input-file|:f [filename] |
--input-pipe|:p [filename] |
--input-string|:s [expression]]
[ --output-file|:F [filename] |
--output-pipe|:P [filename] |
--output-string|:S [$variable] |
--no-output|:N ]
select [xpath] [block]
[ select [xpath] [block] ... ]
description:
EXPERIMENTAL! This command provides a memory efficient (though
slower) way to process selected parts of an XML document with
XSH2. A streaming XML parser (SAX parser) is used to parse the
input. The parser has two states which will be referred to as
A and B below. The initial state of the parser is A.
In the state A, only a limited vertical portion of the DOM
tree is built. All XML data coming from the input stream other
than start-tags are immediately copied to the output stream.
If a new start-tag of an element arrives, a new node is
created in the tree. All siblings of the newly created node
are removed. Thus, in the state A, there is exactly one node
on every level of the tree. After a node is added to the tree,
all the [xpath] expressions following the 'select' keyword are
checked. If none matches, the parser remains in state A and
copies the start-tag to the output stream. Otherwise, the
first expression that matches is remembered and the parser
changes its state to B.
In state B the parser builds a complete DOM subtree of the
element that was last added to the tree before the parser
changed its state from A to B. No data are sent to the output
at this stage. When the subtree is complete (i.e. the
corresponding end-tag for its topmost element is encountered),
the [block] of instructions following the [xpath] expression
that matched is invoked with the root element of the subtree
as the current context node. The commands in [block] are
allowed to transform the whole element subtree or even to
replace it with a different DOM subtree or subtrees. They
must, however, leave intact all ancestor nodes of the subtree.
Failing to do so can result in an error or unpredictable
results.
After the subtree processing [block] returns, all subtrees
that now appear in the DOM tree in the place of the original
subtree are serialized to the output stream. After that, they
are deleted and the parser returns to state A.
Note that this type of processing highly limits the amount of
information the selecting XPath expressions can use. The first
notable fact is, that elements can not be selected by their
content. The only information present in the tree at the time
of the XPath evaluation is the element's name and attributes
plus the same information for all its ancestors (there is no
information at all about its possible child nodes nor of the
node's position within the list of its siblings).
The input parameters below are mutually exclusive. If non is
given, standard input is processed.
'--input-file' or ':f' instructs the processor to stream from
a given file.
'--input-pipe' or ':p' instructs the processor to stream the
output of a given a command.
'--input-string' or ':s' instructs the processor to use the
result of a given expression as the input to be processed.
The output parameters below are mutually exclusive. If none is
given, standard output is used.
'--output-file' or ':F' instructs the processor to save the
output to a given file.
'--output-pipe' or ':P' instructs the processor to pipe the
output to a given command.
'--output-string' or ':S' followed by a variable name
instructs the processor to store the result in the given
variable.
'--no-output' or ':N' instructs the processor to throw the
result away.
END
$HELP{'namespaces'}=[<<'END'];
usage: namespaces [--registered|:r] [[expression]]
description:
For each node in a given node-list lists all namespaces that
are valid the scope of the node. Namespaces are listed in the
form of 'xmlns:prefix="uri"' declarations, preceded by a
canonical xpath of the corresponding node on a separate line.
If '--registered' or ':r' flag is used, list also namespaces
registered with the [register-namespace] command in XSH
syntax.
If called without the '--registered' flag and no [xpath] is
given, lists namespaces in the scope of the current node.
END
$HELP{'xpath-completion'}=[<<'END'];
usage: xpath-completion [expression]
aliases: xpath_completion
description:
If the [expression] is non-zero, enable the TAB completion for
[xpath] expansions in the interactive shell mode, disable it
otherwise. Defaults to on.
This command is equivalent to setting the '$XPATH_COMPLETION'
variable.
END
$HELP{'xpath_completion'}=$HELP{'xpath-completion'};
$HELP{'xpath-axis-completion'}=[<<'END'];
usage: xpath-axis-completion [expression]
aliases: xpath_axis_completion
description:
The following values are allowed: 'always', 'never',
'when-empty'. Note, that all other values (including 1) work
as 'never'!
If the [expression] evaluates to 'always', TAB completion for
XPath expressions always includes axis names.
If the [expression] evaluates to 'when-empty', the TAB
completion list for XPath expressions includes axis names only
if no element name matches the completion.
If the [expression] evaluates to 'never', the TAB completion
list for XPath expressions never includes axis names.
The default value for this option is 'always'.
This command is equivalent to setting the
'$XPATH_AXIS_COMPLETION' variable.
END
$HELP{'xpath_axis_completion'}=$HELP{'xpath-axis-completion'};
$HELP{'doc-info'}=[<<'END'];
usage: doc-info [[document]]
aliases: doc_info
description:
In the present implementation, this command displays
information provided in the '<?xml ...?>' declaration of a
document: 'version, encoding, standalone', plus information
about level of 'gzip' compression of the original XML file and
the original XML file URI.
see also: set-enc set-standalone
END
$HELP{'doc_info'}=$HELP{'doc-info'};
$HELP{'xpath-extensions'}=[<<'END'];
usage: xpath-extensions [[expression]]
aliases: xpath_extensions
description:
'xpath-extensions' remaps all extra XPath extension functions
provided by XSH2 (which by default belong to the namespace
'http://xsh.sourceforge.net/xsh/') to a new namespace given by
[expression]. If the argument is omitted, the functions are
re-registered without any namespace, so that they may be
called without a namespace prefix, just by their function
names. This quite convenient.
Example:
xpath-extensions;
ls grep(//word,"^.*tion$");
see also: set-enc set-standalone
END
$HELP{'xpath_extensions'}=$HELP{'xpath-extensions'};
$HELP{'lineno'}=[<<'END'];
usage: lineno [[expression]]
description:
'lineno' command prints line numbers of all nodes in a given
node-list. Note however, that 'libxml2' only stores line
number information for element nodes.
see also: locate
END
$HELP{'edit-string'}=[<<'END'];
usage: edit-string [--editor|:E [filename]]
[--encoding|:e [encoding]]
[--allow-empty|:0] [expression]
description:
Evaluating given [expression] to a string, save it in a
temporary file, open the file an external editor as a plain
text, and when the editor exits, read and return the result.
The '--editor' (':E') parameter can be used to provide an
editor command, whereas '--encoding' (':e') can be used to
specify character encoding used for communication with the
editor. If the result is empty, the interactive XSH2 shell
asks user for confirmation before returning the result in
order to prevent data loss due to some unexpected error. To
suppress this feature, use '--allow-empty' or ':0' flag.
END
$HELP{'edit'}=[<<'END'];
usage: edit [--editor|:E [filename]]
[--all|:A] [--noindent|:n] [--recover|:r] [--keep-blanks|:k]
[--allow-empty|:0] [--no-coment|:q] [--encoding|:e [encoding]] [expression]
description:
This command may be used to interactively edit parts of a XML
document directly in your favorite editor.
A given [expression] is evaluated to a node-list and the first
the first resulting node is opened in an external editor as a
XML fragment. When the editor exits, the (possibly modified)
fragment is parsed and returned to the original document.
Unless '--no-comment' (':q') flag is used, the XML fragment is
preceded with a XML comment specifying canonical XPath of the
node being edited.
The command returns a node-list consisting of nodes that
resulted from parsing the individual edits.
'--editor' or ':E' option may be used to specify external
editor command. If not specified, environment variables
'EDITOR' and 'VISUAL' are tried first, then 'vi' editor is
used as a fallback.
If '--all' or ':A' flag is present, all nodes from the
node-list are opened in the editor, one at a time.
If '--recover' or ':r' is specified, the parser tries to
recover from possible syntax errors when parsing the resulting
XML.
'--keep-blanks' or ':b' option may be used to force the parser
to include ignorable white space.
If the result saved by the editor is empty, the interactive
XSH2 shell asks user to confirm this was correct. This
confirmation can be suppressed using '--allow-empty' or ':0'
(zero) options.
The '--encoding' or ':e' parameter can be used to specify
character encoding to use when communicating with the external
editor.
Example: Edit all chapter elements (one by one) with emacs
edit --editor 'emacs -nw' --encoding iso-8859-1 --all //chapter
END
$HELP{'xsh:doc'}=[<<'END'];
usage: node-set xsh:doc(node-set)
description:
Returns a node-set consisting of the owner document nodes of
all nodes in the given node-set.
END
$HELP{'xsh:document-uri'}=[<<'END'];
usage: string xsh:document-uri(node-set?)
description:
Returns URI of the document containing the first node in the
given node-set. If called without arguments, or if the
node-set is empty, returns filename of the document containing
the current node.
END
$HELP{'xsh:filename'}=[<<'END'];
usage: string xsh:filename(node-set?)
description:
Same as xsh:document-uri();
END
$HELP{'xsh:base-uri'}=[<<'END'];
usage: string xsh:base-uri(node-set?)
description:
Returns base URI of the first node in the node-set (or the
current node). The function should work on both XML and HTML
documents even if base mechanisms for these are completely
different. It returns the base as defined in RFC 2396 sections
"5.1.1. Base URI within Document Content" and "5.1.2. Base URI
from the Encapsulating Entity". However it does not return the
document base (5.1.3), use document-uri() for this.
END
$HELP{'xsh:resolve-uri'}=[<<'END'];
usage: string xsh:resolve-uri(string, string?)
description:
This function takes one or two arguments: a relative URI and
an optional base URI. If the first argument is a relative URI
reference, this function resolves it against either the given
base URI, if given (which is assumed to be an absolute URI)
or, if base URI not given, against the URI of the current
working directory. If the first argument is an absolute URI
reference, it is returned unchanged.
If the first argument is the zero-length string, returns the
base URI if given and the URI of the current working directory
otherwise.
Note: Resolving a URI does not dereference it (download the
referenced content); it is merely a syntactic operation on two
character strings.
END
$HELP{'xsh:lineno'}=[<<'END'];
usage: node-set xsh:lineno(node-set)
description:
Returns line number of the occurrence of the first node in the
given node-set in its original XML document (if available).
END
$HELP{'xsh:var'}=[<<'END'];
usage: node-set xsh:var(string NAME)
description:
Returns a node-set consisting of nodes stored in a XSH2
node-list variable named 'NAME'.
END
$HELP{'xsh:matches'}=[<<'END'];
usage: boolean xsh:matches(string STR,string PATTERN)
description:
Returns 'true' if 'STR' matches the regular expression
'PATTERN'. Otherwise returns 'false'.
END
$HELP{'xsh:match'}=[<<'END'];
usage: node-set xsh:match(string STR,string PATTERN,string OPTIONS)
description:
Searches a given string for a pattern match specified by a
regular expression 'PATTERN' and returns a node-set consisting
of '<xsh:string>' elements containing portions of the string
matched by the pattern subexpressions enclosed in parentheses.
The OPTIONS string may contain the following flags: 'c' - do
not reset search position on a failed match when /g is in
effect; 'g' - match globally, i.e. find all occurrences; 'i' -
do case insensitive search; 'm' - treat string as multiple
lines (change "^" and "$" from matching the start or end of
the string to matching the start or end of any line anywhere
within the string) 'o' - compile pattern only once; 's' -
treat string as single line (change "." to match any character
whatsoever, even a newline, which normally it would not
match); 'x' - extend your pattern's legibility by permitting
whitespace and comments.
END
$HELP{'xsh:grep'}=[<<'END'];
usage: node-set xsh:grep(node-set NODES, string PATTERN)
description:
Returns a node set consisting of those nodes of 'NODES' whose
content (as returned by the built-in XPath function
'string()') matches the regular expression 'PATTERN'.
END
$HELP{'xsh:substr'}=[<<'END'];
usage: string xsh:substr(string STR,float OFFSET,[float LENGTH])
description:
Extracts a substring out of 'STR' and returns it. First
character is at offset 0.
If 'OFFSET' is negative, starts that far from the end of the
string.
If 'LENGTH' is omitted, returns everything to the end of the
string. If 'LENGTH' is negative, leaves that many characters
off the end of the string.
If 'OFFSET' and 'LENGTH' specify a substring that is partly
outside the string, only the part within the string is
returned. If the substring is beyond either end of the string,
substr() returns empty string and produces a warning.
END
$HELP{'xsh:reverse'}=[<<'END'];
usage: string xsh:reverse(string STR)
description:
Returns a string value same as 'STR' but with all characters
in the opposite order.
END
$HELP{'xsh:lc'}=[<<'END'];
usage: string xsh:lc(string STR)
description:
Returns a lowercased version of 'STR'.
END
$HELP{'xsh:uc'}=[<<'END'];
usage: string xsh:uc(string STR)
description:
Returns a uppercased version of 'STR'.
END
$HELP{'xsh:lcfirst'}=[<<'END'];
usage: string xsh:lcfirst(string STR)
description:
Returns the value of 'STR' with the first character
lowercased.
END
$HELP{'xsh:ucfirst'}=[<<'END'];
usage: string xsh:ucfirst(string STR)
description:
Returns the value of 'STR' with the first character
uppercased.
END
$HELP{'xsh:same'}=[<<'END'];
usage: bool xsh:same(node-set N1, node-set N2)
description:
Returns 'true' if the given node sets both contain the same
node (in XPath, this can also be expressed as
'count(N1|N2)+count(N1)+count(N2)=3').
END
$HELP{'xsh:max'}=[<<'END'];
usage: float xsh:max(object EXPRESSION, ...)
description:
Returns the maximum of numeric values computed from given
'EXPRESSION'(s). If 'EXPRESSION' evaluates to a node-set,
string values of individual nodes are used.
END
$HELP{'xsh:min'}=[<<'END'];
usage: float xsh:min(object EXPRESSION, ...)
description:
Returns the minimum of numeric values computed from given
'EXPRESSION'(s). If 'EXPRESSION' evaluates to a node-set,
string values of individual nodes are used.
END
$HELP{'xsh:strmax'}=[<<'END'];
usage: string xsh:strmax(object EXPRESSION, ...)
description:
Returns a string value computed as the maximum (in
lexicographical order) of all string values computed from
given 'EXPRESSION'(s). If 'EXPRESSION' evaluates to a
node-set, string values of individual nodes are used.
END
$HELP{'xsh:strmin'}=[<<'END'];
usage: string xsh:strmin(object EXPRESSION, ...)
description:
Returns a string value computed as the minimum (in
lexicographical order) of all string values computed from
given 'EXPRESSION'(s). If 'EXPRESSION' evaluates to a
node-set, string values of individual nodes are used.
END
$HELP{'xsh:sum'}=[<<'END'];
usage: float xsh:sum(object EXPRESSION, ...)
description:
Returns the sum of numerical value computed from given
'EXPRESSION'(s). If 'EXPRESSION' evaluates to a node-set,
string values of individual nodes are used.
END
$HELP{'xsh:join'}=[<<'END'];
usage: string xsh:join(string DELIM, object EXPRESSION,...)
description:
Joins the separate string values computed from 'EXPRESSION'(s)
into a single string with fields separated by the value of
'DELIM', and returns that new string. If 'EXPRESSION'
evaluates to a node-set, joins string values of individual
nodes.
END
$HELP{'xsh:subst'}=[<<'END'];
usage: string xsh:subst(string STR,string REGEXP,string
REPLACEMENT, [string OPTIONS])
description:
Acts in the very same way as perl substitution operation
'STRING =~ s/REGEXP/REPLACEMENT/OPTIONS', returning the
resulting string. Searches a string for a pattern, and if
found, replaces that pattern with the replacement text. If the
'REPLACEMENT' string contains a '$' that looks like a
variable, the variable will be interpolated into the
'REPLACEMENT' at run-time. Options are:
'e' - evaluate 'REPLACEMENT' as a Perl expression,
'g' - replace globally, i.e., all occurrences,
'i' - do case-insensitive pattern matching,
'm' - treat string as multiple lines, that is, change '^' and
'$' from matching the start or end of the string to matching
the start or end of any line anywhere within the string,
's' - treat string as single line, that is, change '.' to
match any character whatsoever, even a newline, which normally
it would not match,
'x' - use extended regular expressions.
END
$HELP{'xsh:sprintf'}=[<<'END'];
usage: string xsh:sprintf(string FORMAT,object EXPRESSION,...)
description:
Returns a string formatted by the usual 'printf' conventions
of the C library function 'sprintf' and 'sprintf' Perl
function.
See C documentation for an explanation of the general
principles and Perl documentation for a list of supported
formatting conversions.
END
$HELP{'xsh:serialize'}=[<<'END'];
usage: string xsh:serialize(node-set N,...)
description:
Serializes nodes of given node-set(s) into XML strings and
returns concatenation of those strings.
END
$HELP{'xsh:parse'}=[<<'END'];
usage: node-set xsh:parse(string XML-STRING)
description:
This function runs XML parser on 'XML-STRING' and returns a
node-set consisting of the top-level nodes of the resulting
document node.
END
$HELP{'xsh:current'}=[<<'END'];
usage: node-set xsh:current()
description:
This function (very similar to XSLT 'current()' extension
function) returns a node-set having the current node as its
only member.
END
$HELP{'xsh:path'}=[<<'END'];
usage: string xsh:path(node-set NODE)
description:
This function returns a string containing canonical XPath
leading to 'NODE'.
see also: pwd
END
$HELP{'xsh:if'}=[<<'END'];
usage: object xsh:if(object CONDITION, object YES, object NO)
description:
This function returns the 'YES' object if 'CONDITION' is an
non-empty node-set or a string, boolean or integer evaluating
to non-zero boolean. Otherwise the 'NO' object is returned.
END
$HELP{'xsh:new-attribute'}=[<<'END'];
usage: node-set xsh:new-attribute(string NAME1,string
VALUE1,[string NAME2, string VALUE2, ...])
description:
Return a node-set consisting of newly created attribute nodes
with given names and respective values.
END
$HELP{'xsh:new-element'}=[<<'END'];
usage: node-set xsh:new-element(string NAME,[string ATTR1-NAME1,
string ATTR-VALUE1, ...])
description:
Create a new element node with given 'NAME' and optionally
attributes with given names and values and return a node-set
containing the new node as its only member.
END
$HELP{'xsh:new-element-ns'}=[<<'END'];
usage: node-set xsh:new-element-ns(string NAME,string NS,[string ATTR1-NAME1,
string ATTR-VALUE1, ...])
description:
Create a new element node with given 'NAME' and namespace-uri
'NS' and optionally attributes with given names and values and
return a node-set containing the new node as its only member.
END
$HELP{'xsh:new-text'}=[<<'END'];
usage: node-set xsh:new-text(string DATA)
description:
Create a new text node containing given 'DATA' and return a
node-set containing the new node as its only member.
END
$HELP{'xsh:new-comment'}=[<<'END'];
usage: node-set xsh:new-comment(string DATA)
description:
Create a new comment node containing given 'DATA' and return a
node-set containing the new node as its only member.
END
$HELP{'xsh:new-pi'}=[<<'END'];
usage: node-set xsh:new-pi(string NAME, [string DATA])
description:
Create a new processing instruction node node with given
'NAME' and (optionally) given 'DATA' and return a node-set
containing the new node as its only member.
END
$HELP{'xsh:new-cdata'}=[<<'END'];
usage: node-set xsh:new-cdata(string DATA)
description:
Create a new cdata section node node filled with given 'DATA'
and return a node-set containing the new node as its only
member.
END
$HELP{'xsh:new-chunk'}=[<<'END'];
usage: node-set xsh:new-chunk(string XML)
description:
This is just an alias for [xsh:parse]. It parses given piece
of XML and returns a node-set consisting of the top-level
element within the parsed tree.
END
$HELP{'xsh:map'}=[<<'END'];
usage: node-set xsh:map(node-set NODE, string XPATH)
description:
This function is very similar to EXSLT 'dynamic:map' function.
The description below is almost literally taken from the EXSLT
specification.
The 'xsh:map' function evaluates the expression passed as the
second argument for each of the nodes passed as the first
argument, and returns a node-set of those values.
The expressions are evaluated relative to the nodes passed as
the first argument. In other words, the value for each node is
calculated by evaluating the XPath expression with all context
information being the same as that for the call to the
'xsh:map' function itself, except for the following:
1) the context node is the node whose value is being
calculated, 2) the context position is the position of the
node within the node set passed as the first argument to the
'xsh:map' function, arranged in document order, and 3) the
context size is the number of nodes passed as the first
argument to the dyn:map function.
If the expression string passed as the second argument is an
invalid XPath expression (including an empty string), this
function returns an empty node set.
If 'XPATH' evaluates as a node set, the 'xsh:map' function
returns the union of the node sets returned by evaluating the
expression for each of the nodes in the first argument. Note
that this may mean that the node set resulting from the call
to the 'xsh:map' function contains a different number of nodes
from the number in the node set passed as the first argument
to the function.
If 'XPATH' evaluates as a number, the 'xsh:map' function
returns a node set containing one 'xsh:number' element
(namespace 'http://xsh.sourceforge.net/xsh/') for each node in
the node set passed as the first argument to the dyn:map
function, in document order. The string value of each
'xsh:number' element is the same as the result of converting
the number resulting from evaluating the expression to a
string as with the number function, with the exception that
Infinity results in an 'xsh:number' holding the highest number
the implementation can store, and -Infinity results in an
'xsh:number' holding the lowest number the implementation can
store.
If 'XPATH' evaluates as a boolean, the 'xsh:map' function
returns a node set containing one 'xsh:boolean' element
(namespace 'http://xsh.sourceforge.net/xsh/') for each node in
the node set passed as the first argument to the 'xsh:map'
function, in document order. The string value of each
'xsh:boolean' element is 'true' if the expression evaluates as
true for the node, and is empty if the expression evaluates as
false.
Otherwise, the 'xsh:map' function returns a node set
containing one 'xsh:string' element (namespace
'http://xsh.sourceforge.net/xsh/') for each node in the node
set passed as the first argument to the 'xsh:map' function, in
document order. The string value of each 'xsh:string' element
is the same as the result of converting the result of
evaluating the expression for the relevant node to a string as
with the string function.
see also: xsh:evaluate
END
$HELP{'xsh:evaluate'}=[<<'END'];
usage: node-set xsh:evaluate(string XPATH)
description:
This function is very similar to EXSLT 'dynamic:evaluate'
function. The description below is almost literally taken from
the EXSLT specification.
The 'xsh:evaluate' function evaluates a string as an XPath
expression and returns the resulting value, which might be a
boolean, number, string, node set, result tree fragment or
external object. The sole argument is the string to be
evaluated.
The string is always evaluated exactly as if it had been
literally included in place of the call to the 'xsh:evaluate'
function.
In other words, the context information used when evaluating
the XPath expression passed as the argument to the
'xsh:evaluate' function is exactly the same as the context
information used when evaluating the 'xsh:evaluate' function.
This context information includes:
1. the context node, such that paths are evaluated relative
to the context node at the point where the 'xsh:evaluate'
function is called
2. the context position, such that the expression can
contain calls to the position function
3. the context size, such that the expression can contain
calls to the last function
4. variable bindings, such that the expression can contain
variable references
5. function library, such that the expression can contain
calls to extension functions
6. namespace declarations, such that paths can contain
prefixes the current node, such that the expression can
contain calls to the current function
If the expression string passed as the second argument is an
invalid XPath expression (including an empty string), this
function returns an empty node set.
You should only use this function if the expression must be
constructed dynamically - otherwise it is much more efficient
to use the expression literally. For expressions that simply
give an element or attribute's name (to select a child element
or attribute), it is more efficient to use an expression in
the style:
*[name() = $expression]
see also: xsh:map
END
$HELP{'xsh:split'}=[<<'END'];
usage: node-set xsh:split(string PATTERN, string STRING)
description:
This function provides direct access to the very powerful Perl
function 'split'. It splits 'STRING' to a list of fields.
'PATTERN' is a regular expression specifying strings
delimiting individual fields of 'STRING'. If 'PATTERN' is
empty, 'STRING' is split to individual characters. If the
regular expression in 'PATTERN' is enclosed in brackets, then
strings matching 'PATTERN' are also included in the resulting
list.
The function returns a node-set consisting of newly created
'<xsh:string>' elements containing individual strings of the
resulting list as their only text child nodes.
END
$HELP{'xsh:times'}=[<<'END'];
usage: node-set xsh:times(string STRING, float COUNT)
description:
This function returns a string resulting from concatenation of
'COUNT' copies of 'STRING'. 'COUNT' must be a non-negative
integer value.
END
$HELP{'xsh:id2'}=[<<'END'];
usage: node-set xsh:id2(node-set DOC, string IDs)
description:
This function is like XPath built-in 'id(IDs)' function,
except that it operates on the document specified in the first
argument. It returns a node-set consisting of nodes that
belong to the document DOC and whose ID belongs to the list of
space separated IDs specified in the second argument.
END
$HELP{'xsh:lookup'}=[<<'END'];
usage: node-set xsh:lookup(string VARNAME, string KEY)
description:
This function is similar to XSLT 'key()' function. It returns
a node-set stored in a hash VARNAME under the key KEY. The
VARNAME must be a name of a lexical or global XSH variable
containing a Perl hash reference.
see also: hash
END
$HELP{'xsh:document'}=[<<'END'];
usage: node-set xsh:document(string URL)
description:
Looks up among the currently open document the one whose
filename is same as the given URL and returns the
corresponding document node. If no document's filename matches
exactly the given URL, then several heuristic matches are
tried: if the URI is a relative filename, it is tilde-expanded
and resolved (using the current working directory as a base)
and the lookup is restarted with the absolute filename;
finally, a lookup identifying filenames with URLs of the
file:// protocol is attempted. If the lookup fails completely,
an empty node set is returned.
see also: hash
END
$HELP{'xsh:documents'}=[<<'END'];
usage: node-set xsh:documents()
description:
Returns a node-set consisting of the document nodes of all
currently open documents.
see also: hash
END
$HELP{'xsh:span'}=[<<'END'];
usage: node-set xsh:span(node-set START,node-set END)
description:
Returns a node-set which forms a span of sibling nodes
starting at START node and ending at END node (only the first
node of each of the nodesets is used). It is an error if the
START node and END node are not siblings.
END
$HELP{'xsh:context'}=[<<'END'];
usage: node-set xsh:context(node-set NODE, float BEFORE, float AFTER)
description:
Returns a node-set of sibling nodes surrounding NODE. The span
consists of (up to) BEFORE-many nodes immediately preceding
NODE, the NODE itself, and (up to) AFTER-many nodes
immediately following NODE. If the AFTER is not given, AFTER
is set equal to BEFORE.
END
$HELP{'call'}=[<<'END'];
usage: call [expression] [[expression] ...]
description:
Call a subroutine whose name is computed by evaluating the
first argument [expression]. All other expressions are
evaluated too and the results are passed to the subroutine as
arguments.
This command should only be used if the name of the subroutine
isn't known at the compile time. Otherwise it is recommended
to use a direct subroutine call of the form:
subroutine-name [argument1 argument2 ...]
Example:
def a $arg { echo "A says" $arg }
def b $arg { echo "B says" $arg }
a "hallo!"; # call subroutine a
b "hallo!"; # call subroutine b
call { chr(ord("a")+rand(2)) } "surprise!"; # call a or b randomly
see also: def return
END
$HELP{'Documents'}=[<<'END'];
Files/Documents
---------------
XSH2 is designed as an environment for querying and manipulating XML and
HTML documents. Use [open] or [create] commands to load an XML or HTML
document from a local file, external URL (such as http:// or ftp://),
string or pipe. XSH2 can optionally validate the document during parse
process (see [validation] and [load-ext-dtd]). Parsed documents are
stored in memory as DOM trees, that can be [navigated] and [manipulated]
with XSH2 commands and XPath language, whose names and syntax make
working with the DOM tree a flavor of working in a UNIX filesystem.
A parsed document is usually stored in a variable. XSH2 shares variables
with the XPath engine, so if e.g. '$doc' is a XSH2 variable holding a
document (or, more generally any node-set), then '$doc//section/title' is
an XPath expression selecting all 'title' subelements of all 'section'
elements within the (sub)tree of $doc.
Although XSH2 is able to parse remote documents via 'http://' or
'ftp://', it is only able to save them locally. To upload a document to a
remote server (e.g. using FTP) or to store it into a database, use [save]
command with a '--pipe' parameter, in connection with an external program
able to store its standard input (XML) to the desired location. You can
also use similar parameter with [open] in order to parse documents from
standard output of some external program.
Example: Store a XSH2 document on a remote machine using the Secure Shell
xsh> save --pipe "ssh my.remote.org 'cat > test.xml'" $doc
Related help items:
backups, catalog, clone, close, create, documents, index, nobackups,
open, process-xinclude, save, set_filename, stream,
switch-to-new-documents
END
$HELP{'Navigation'}=[<<'END'];
Tree navigation
---------------
With XSH2, it is possible to browse a [document tree] (XML data
represented as a DOM-tree) as if it was a local filesystem, except that
[XPath] expressions are used instead of ordinary directory paths.
To mimic the filesystem navigation as closely as possible, XSH2 contains
several commands named by analogy of UNIX filesystem commands, such as
[cd], [ls] and [pwd].
The current position in the document tree is called the current node.
Current node's XPath may be queried with [pwd] command. In the
interactive shell, current node is also displayed in the command line
prompt. (Since there may be multiple document trees open at the same
time, XSH2 tries to locate a variable holding the current document and
use it to fully qualify current node's XPath in the XSH2 prompt.)
Remember, that beside [cd] command, current node (and document) is also
silently changed by [open] command, [create] command and temporarily also
by the node-list variant of the [foreach] loop without a loop variable.
XPath expressions are always evaluated in context of the current node.
Different documents can be accessed through variables: '$doc/foo[1]/bar'.
Example: XSH2 shell
$scratch:/> $docA := open "testA.xml"
$docA/> $docB := open "testB.xml"
$docB/> pwd
/
$docB/> cd $docA/article/chapter[title='Conclusion']
$docA/article/chapter[5]> pwd
/article/chapter[5]
$docA/article/chapter[5]> cd previous-sibling::chapter
$docA/article/chapter[4]> cd ..
$docA/article> cd $docB
$docB:/> ls
<?xml version="1.0" encoding="utf-8"?>
<article>...</article>
Related help items:
canonical, cd, fold, locate, ls, pwd, register-function, unfold,
unregister-function
END
$HELP{'Manipulation'}=[<<'END'];
Tree modification
-----------------
XSH2 not only provides ways to browse and inspect the DOM tree but also
many commands to modify its content by various operations, such as
copying, moving, and deleting its nodes as well as creating completely
new nodes or XML fragments and attaching them to it. It is quite easy to
learn these commands since their names or aliases mimic their well-known
filesystem analogies. On the other hand, many of these commands have two
versions one of which is prefixed with a letter "x". This "x" stands for
"cross", thus e.g. [xcopy] should be read as "cross copy". Let's explain
the difference on the example of [xcopy].
In a copy operation, you have to specify what nodes are to be copied and
where to, in other words, you have to specify the source and the target.
XSH2 is very much XPath-based so, XPath is used here to specify both of
them. However, there might be more than one node that satisfies an XPath
expression. So, the rule of thumb is that the "cross" variant of a
command places one and every of the source nodes to the location of one
and every destination node, while the plain variant works one-by-one,
placing the first source node to the first destination, the second source
node to the second destination, and so on (as long as there are both
source nodes and destinations left).
Example:
$scratch/> $a := create "<X><A/><Y/><A/></X>";
$a/> $b := create "<X><B/><C/><B/><C/><B/></X>";
$b/> xcopy $a//A replace $b//B;
$b/> copy $b//C before $a//A;
$b/> ls $a;
<?xml version="1.0" encoding="utf-8"?>
<X><C/><A/><Y/><C/><A/></X>
$b/> ls $b;
<?xml version="1.0" encoding="utf-8"?>
<X><A/><A/><C/><A/><A/><C/><A/><A/></X>
As already indicated by the example, another issue of tree modification
is the way in which the destination node determines the target location.
Should the source node be placed before, after, or somewhere among the
children of the resulting node? Or maybe, should it replace it
completely? This information has to be given in the [location] argument
that usually precedes the destination XPath.
Now, what happens if source and destination nodes are of incompatible
types? XSH2 tries to avoid this by implicitly converting between node
types when necessary. For example, if a text, comment, and attribute node
is copied into, before or after an attribute node, the original value of
the attribute is replaced, prepended or appended respectively with the
textual content of the source node. Note however, that element nodes are
never converted into text, attribute or any other textual node. There are
many combinations here, so try yourself and see the results.
You may even use some more sophisticated way to convert between node
types, as shown in the following example, where an element is first
commented out and than again uncommented. Note, that the particular
approach used for resurrecting the commented XML material works only for
well-balanced chunks of XML.
Example: Using string variables to convert between different types of nodes
$doc := create <<EOF;
<?xml version='1.0'?>
<book>
<chapter>
<title>Intro</title>
</chapter>
<chapter>
<title>Rest</title>
</chapter>
</book>
EOF
# comment out the first chapter
ls //chapter[1] |> $chapter_xml;
insert comment $chapter_xml replace //chapter[1];
ls / 0;
# OUTPUT:
<?xml version="1.0"?>
<book>
<!-- <chapter>
<title>Intro</title>
</chapter>
-->
<chapter>
<title>Rest</title>
</chapter>
</book>
# un-comment the chapter
$comment = string(//comment()[1]);
insert chunk $comment replace //comment()[1];
ls / 0;
# OUTPUT:
<?xml version="1.0"?>
<book>
<chapter>
<title>Intro</title>
</chapter>
<chapter>
<title>Rest</title>
</chapter>
</book>
Related help items:
change-ns-prefix, change-ns-uri, clone, copy, declare-ns, edit,
edit-string, hash, insert, map, move, normalize, process-xinclude,
remove, rename, set, set-dtd, set-enc, set-ns, set-standalone, sort,
strip-whitespace, wrap, wrap-span, xcopy, xinsert, xmove, xslt, xupdate
END
$HELP{'Flow'}=[<<'END'];
Flow control
------------
As almost every scripting language, XSH2 supports subroutines, various
conditional statements, loops and even exceptions.
Related help items:
call, def, do, eval, exit, foreach, if, ifinclude, include, iterate,
last, next, prev, redo, return, run-mode, stream, test-mode, throw, try,
undef, unless, while
END
$HELP{'Information'}=[<<'END'];
Retrieving more information
---------------------------
Beside the possibility to browse the DOM tree and list some parts of it
(as described in [Navigation]), XSH2 provides commands to obtain other
information related to open documents as well as the XSH2 interpreter
itself. These commands are listed bellow.
Related help items:
apropos, canonical, count, defs, doc-info, documents, dtd, enc, get,
help, lineno, locate, ls, namespaces, print, pwd, settings, validate,
variables, version
END
$HELP{'Namespaces'}=[<<'END'];
Namespaces in XML and XPath
---------------------------
Namespaces provide a simple method for qualifying element and attribute
names in XML documents. Namespaces are represented by a namespace URI
but, since the URI can be very long, element and attribute names are
associated with a namespace using a namespace prefix (see the W3C
recommendation for details). In an XML document, a prefix can be
associated with a namespace URI using a declaration which takes form of
special attribute of the form 'xmlns:prefix="namespace uri"' on an
element. The scope of the namespace declaration is then the subtree of
the element carrying the special 'xmlns:prefix' attribute (and includes
attributes of the element). Moreover, a default namespace can be declared
using just 'xmlns="namespace uri"'. In that case all unprefixed element
names in the scope of such a declaration belong to the namespace. An
unprefixed element which is not in scope of a default namespace
declaration does not belong to any namespace. It is recommended not to
combine namespaced elements and non-namespaced elements in a single
document. Note that regardless of default namespace declarations,
unprefixed attributes do not belong to any namespace (because they are
uniquely determined by their name and the namespace and name of the the
element which carries them).
XSH2 tries to deal namespace declarations transparently (creating them if
necessary when nodes are copied between different documents or scopes of
namespace declarations). Most commands which create new elements or
attributes provide means to indicate a namespace. In addition, XSH2
provides commands [declare-ns], [set-ns], [change-ns-uri], and
[change-ns-prefix] to directly manipulate XML namespace declarations on
the current node.
Since XSH2 is heavily XPath-based, it is important to remember that XPath
1.0 maps prefixes to namespaces independently of the declarations in the
current document. The mapping is instead provided via so called XPath
context. Namespaces can be tested in XPath either using the built-in
'namespace-uri()' function, but it is more convenient to use namespace
prefixes associated with namespace URIs in the XPath context. This
association is independent of the documents to which the XPath expression
is applied and can be established using the command [register-namespace].
Additional, XSH2 automatically propagates the namespace association in
the scope of the current node to the XPath context, so that per-document
prefixes in the current scope can also be used.
IMPORTANT: XPath 1.0 has no concept of a default namespace. Unprefixed
names in XPath only match names which have no namespace. So, if the
document uses a default namespace, it is required to associate a
non-empty prefix with the default namespace via [register-namespace] and
add that prefix to names in XPath expressions intended to match nodes in
the default namespace.
Example: Manipulating nodes in XHTML documents
open "index.xhtml";
$xhtmlns = "http://www.w3.org/1999/xhtml";
register-namespace x $xhtmlns;
wrap --namespace $xhtmlns '<font color="blue">' //x:a[@href];
# or
wrap '<x:font color="blue">' //x:a[@href];
In the preceding example we associate the (typically default) namespace
of XHTML documents with the prefix 'x'. We than use this prefix to match
all links ('a' elements) in the document. Note that we do not write
'@x:href' to match the '@href' attribute because unprefixed attributes do
not belong to the default namespace. The [wrap] command is used to create
new containing elements for the nodes matched by the XPath expression. We
may either specify the namespace of the containing element explicitly,
using '--namespace' option, or implicitly, by using a prefix associated
with the namespace in the XPath context. In the latter case, XSH2 chooses
a suitable prefix declared for the namespace in the document scope (in
this case the default, i.e. no, prefix), adding a new namespace
declaration if necessary.
Related help items:
change-ns-prefix, change-ns-uri, declare-ns, namespaces,
register-namespace, register-xhtml-namespace, register-xsh-namespace,
set-ns, unregister-namespace
END
$HELP{'Argtypes'}=[<<'END'];
Argument Types
--------------
XSH2 commands accept arguments of various types, usually expressed as
Perl or XPath [expression]s. Unlike in most languages, individual XSH2
commands may evaluate the same expression differently, usually to enforce
a result of a certain type (such as a node-list, a string, a number, a
filename, a node name, etc.). See [expression] and individual argument
types for more information.
END
$HELP{'Variables'}=[<<'END'];
Variables
---------
In XSH2, like in Perl and XPath, [variable names] are are prefixed with a
dollar sign ($). Variables can contain arbitrary Perl Scalar (string,
number, array reference, hash reference or an object reference). XPath
objects are transparently mapped to Perl objects via XML::LibXML objects.
Values can be assigned to variables either by simple [assignments] of the
form '$variable = [expression]', where the right hand side is an
expression, or by command [assignments] of the form '$variable :=
[command]', where the right hand side is a XSH2 command, or by capturing
the output of some command with a variable redirection of the following
form:
command |> $variable;
XSH2 expressions are evaluated either by XPath engine or by Perl (the
latter only happens if the entire expression is enclosed with braces
'{...}'), and both Perl and XPath can access all XSH2 variables
transparently (Perl expressions may even assign to them).
A simple simple expression consisting of a variable name (e.g.
'$variable') is always evaluated by the XPath engine and the result is
the content of the variable as it appears to the XPath data model. Since
in XPath object cannot be void (undefined), XPath engine complains, if
the value of the variable is undefined. On the other hand, expressions
like '{$variable}' are evaluated by Perl, which results in the value of
the variable as seen by Perl.
Variables can also be used as macros for complicated XPath expressions.
Any occurrence of a substring of the form '${variable}' in an XPath
expression is interpolated to the value of '$variable' (if '$variable'
contains an object rather than a string or number, then the object is
cast to string first) before the entire expression is evaluated. So, for
example, if '${variable}' contains string "'chapter[title]'" (without the
quotes), then the XPath expression '//sect1/${variable}/para'
interpolates to '//sect1/chapter[title]/para' prior to evaluation.
To display the current value of a variable, use either [print] or (in
case of a global variables - the distinction is discussed below) the
command [variables]:
Example:
xsh> $b="my_document";
xsh> $file="${b}s.xml";
xsh> $f := open $file;
xsh> ls //$b[count(descendant::para)>10]
xsh> print $b
my_document
xsh> variables
...
$b='my_document';
...
$file='my_documents.xml';
...
Variables can also serve as containers for documents and can be used to
store lists of nodes that result from evaluating an XPath expression
(a.k.a. XPath node-sets). This is especially useful when a sequence of
commands is to be performed on some fixed set of nodes and repetitive
evaluation of the same XPath expression would be lengthy. XPath node-sets
are represented by 'XML::LibXML::NodeList' Perl objects (which is simply
a array reference blessed to the above class, which provides some simple
operator overloading). In XPath, by a node-set by definition can only
contain a single copy of each node and the nodes within a node-set are
processed in the same order as they appear in the XML document. Having
XPath node-sets represented by a list gives us the advantage of having
the possibility to process the list in a different order than the one
implied by the document (which is what happens if a variable containing a
node-list is evaluated by Perl rather than XPath), see an example below.
Example:
xsh> $creatures = //creature[@status='alive']
# process creatures in the document order:
xsh> foreach $creature print @name;
# process creatures in the reverse document order:
xsh> foreach { reverse @$creature } print @name;
# append some more nodes to a node-list (using a variant of
# a simple assignment)
xsh> $creatures += //creature[@status='dead'];
# again, we can process creatures in order implied by the document:
xsh> foreach $creature print @name;
# but we can also process first living and then dead creatures,
# since this is how they are listed in $creature
xsh> foreach {$creature} print @name;
# same as the above is
xsh> foreach {@$creature} print @name;
XSH2 variables are either globally or lexically scoped. Global variables
need not to be declared (they can be directly assigned to), whereas
lexical variables must be declared using the command [my]. Global
variable assignment may also be made temporal for the enclosing block,
using [local].
Example:
$var1 = "foo"; # a global variable requires no declaration
local $var1 $var2 $var3; # localizes global variables
$var1 = "bar"; # assignment to a localized variable is temporary
local $var4 = "foo"; # localized assignment
my $var1 $var $var3; # declares lexical variables
my $var1 = "foo"; # lexical variable declaration with assignment
Lexical variables are only defined in the scope of current block or
subroutine. There is no way to refer to a lexical variable form outside
of the block it was declared in, nor from within a nested subroutine
call. Of course, lexical variables can be referred to from nested blocks
or Perl expressions (where they behave just like Perl's lexical
variables).
On the other hand, global or localized XSH2 variables are just Perl
Scalar variables belonging to the 'XML::XSH2::Map' namespace, which is
also the default namespace for any Perl code evaluated from XSH2 (so
there's no need to use this prefix explicitly in Perl expressions, unless
of course there is a lexical variable in the current scope with the
same).
Localizing a variable using the 'local' keyword makes all assignments to
it occurring in the enclosing block temporary. The variable itself
remains global, only its original value is restored at the end of the
block that localized it.
In all above cases, it is possible to arbitrarily intermix XSH2 and Perl
assignments:
Example:
xsh> ls //chapter[1]/title
<title>Introduction</title>
xsh> $a=string(//chapter[1]/title)
xsh> perl { $b="CHAPTER 1: ".uc($a); }
xsh> print $b
CHAPTER 1: INTRODUCTION
Although all XSH2 variables are in fact Perl Scalars, it is still
possible to store Perl Array or Hash value to a XSH2 variable via
reference. The following example demonstrates using Perl Hashes to
collect and print some simple racial statistics about the population of
Middle-Earth:
Example:
my $races;
foreach a:/middle-earth/creature {
my $race=string(@race);
perl { $races->{$race}++ };
}
print "Middle-Earth Population (race/number of creatures)"
print { map "$_/$races->{$_}\n" keys(%$races); };
Related help items:
assign, local
END
$HELP{'Redirection'}=[<<'END'];
Command output redirection
--------------------------
WARNING: XSH2 redirection syntax is not yet finished. It is currently the
same as in XSH1 but this may be changed in the future releases.
Output redirection can be used to pipe output of some XSH [command] to
some external program, or to capture it to a variable. Redirection of
output of more than one XSH command can be achieved using the [do]
command.
Redirect output to an external program
--------------------------------------
The syntax for redirecting the output of a XSH command to an external
program, is 'xsh-command | shell-command ;', where 'xsh-command' is any
XSH2 command and 'shell-command' is any command (or code) recognized by
the default shell interpreter of the operating system (i.e. on UNIX
systems by '/bin/sh' or '/bin/csh', on Windows systems by 'cmd'). The
shell command may contain further redirections (as supported by the
system shell interpreter), but should not contain semicolons, except
when the whole shell command is enclosed in brackets.
Example: Use well-known UNIX commands to filter XPath-based XML listing
from a document and count the results
xsh> ls //something/* | grep foo | wc
Capture output to a variable
----------------------------
The syntax for capturing the output of an XSH command to a variable is
'xsh-command |> $variable', where 'xsh-command' is any XSH [command]
and '$variable' is any valid name for a [variable].
Example: Store the number of all words in a variable named count.
xsh> count //words |> $count
END
$HELP{'Configuration'}=[<<'END'];
Global settings
---------------
The commands listed below can be used to modify the default behavior of
the XML parser or XSH2 itself. Some of the commands switch between two
different modes according to a given expression (which is expected to
result either in zero or non-zero value). Other commands also working as
a flip-flop have their own explicit counterparts (e.g. [verbose] and
[quiet] or [debug] and [nodebug]). This inconsistency is due to
historical reasons.
The [encoding] and [query-encoding] settings allow to specify character
encodings of user's input and XSH2's own output. This is particularly
useful when you work with UTF-8 encoded documents on a console which only
supports 8-bit characters.
The [settings] command displays current settings by means of XSH2
commands. Thus it can not only be used to review current values, but also
to store them for future use, e.g. in ~/.xsh2rc file.
Example:
xsh> settings | cat > ~/.xsh2rc
Related help items:
backups, debug, empty-tags, encoding, indent, keep-blanks, load-ext-dtd,
nobackups, nodebug, parser-completes-attributes, parser-expands-entities,
parser-expands-xinclude, pedantic-parser, query-encoding, quiet,
recovering, register-function, register-namespace,
register-xhtml-namespace, register-xsh-namespace, run-mode, settings,
skip-dtd, switch-to-new-documents, test-mode, unregister-function,
unregister-namespace, validation, verbose, xpath-axis-completion,
xpath-completion, xpath-extensions
END
$HELP{'Perl_shell'}=[<<'END'];
Interacting with Perl and Shell
-------------------------------
Along with XPath, Perl is one of two XSH2 expression languages, and
borrows XSH2 its great expressive power. Perl is a language optimized for
scanning arbitrary text files, extracting information from those text
files, and printing reports based on that information. It has built-in
regular expressions and powerful yet easy to learn data structures
(scalars, arrays, hash tables). It's also a good language for many system
management tasks. XSH2 itself is written in Perl (except for the XML
engine, which uses libxml2 library written in C by Daniel Veillard).
Calling Perl
------------
Perl [expressions or blocks of code] can either be used as arguments to
any XSH2 command. One of them is [perl] command which simply evaluates
the given Perl block. Other commands, such as [map], even require Perl
expression argument and allow quickly change DOM node content. Perl
expressions may also provide lists of strings to iterate over with a
[foreach] loop, or serve as conditions for [if], [unless], and [while]
statements.
To prevent conflict between XSH2 internals and the evaluated Perl code,
XSH2 runs such code in the context of a special namespace
'XML::XSH2::Map'. As described in the section [Variables], XSH2 string
variables may be accessed and possibly assigned from Perl code in the
most obvious way, since they actually are Perl variables defined in the
'XML::XSH2::Map' namespace.
The interaction between XSH2 and Perl actually works the other way
round as well, so that you may call back XSH2 from the evaluated Perl
code. For this, Perl function 'xsh' is defined in the 'XML::XSH2::Map'
namespace. All parameters passed to this function are interpreted as
XSH2 commands.
Moreover, the following Perl helper functions are defined:
'xsh(string,....)' - evaluates given string(s) as XSH2 commands.
'call(name)' - call a given XSH2 subroutine.
'count(string)' - evaluates given string as an XPath expression and
returns either literal value of the result (in case of boolean, string
and float result type) or number of nodes in a returned node-set.
'literal(string|object)' - if passed a string, evaluates it as a XSH2
expression and returns the literal value of the result; if passed an
object, returns literal value of the object. For example,
'literal('$doc/expression')' returns the same value as
'count('string($doc/expression)')'.
'serialize(string|object)' - if passed a string, it first evaluates the
string as a XSH2 expression to obtain a node-list object. Then it
serializes the object into XML. The resulting string is equal to the
output of the XSH2 command [ls] applied on the same expression or
object expression only without indentation and folding.
'type(string|object)' - if passed a string, it first evaluates the
string as XSH2 expression to obtain a node-list object. It returns a
list of strings representing the types of nodes in the node-list
(ordered in the canonical document order). The returned type strings
are: 'element', 'attribute', 'text', 'cdata', 'pi', 'entity_reference',
'document', 'chunk', 'comment', 'namespace', 'unknown'.
'nodelist(string|object,...)' - converts its arguments to objects if
necessary and returns a node-list consisting of the objects.
'xpath(string, node?)' - evaluates a given string as an XPath
expression in the context of a given node and returns the result.
'echo(string,...)' - prints given strings on XSH2 output. Note, that in
the interactive mode, XSH2 redirects all output to a specific terminal
file handle stored in the variable '$OUT'. So, if you for example mean
to pipe the result to a shell command, you should avoid using STDOUT
filehandle directly. You may either use the usual 'print' without a
filehandle, use the 'echo' function, or use '$OUT' as a filehandle.
In the following examples we use Perl to populate the Middle-Earth with
Hobbits whose names are read from a text file called 'hobbits.txt',
unless there are some Hobbits in Middle-Earth already.
Example: Use Perl to read text files
unless (//creature[@race='hobbit']) {
perl {
open my $fh, "hobbits.txt" };
@hobbits=<$file>;
close $fh;
}
foreach { @hobbits } {
copy xsh:new-element("creature","name",.,"race","hobbit")
into m:/middle-earth/creatures;
}
}
Example: The same code as a single Perl block
perl {
unless (count(//creature[@race='hobbit'])) {
open my $file, "hobbits.txt";
foreach (<$file>) {
xsh(qq{insert element "<creature name='$_' race='hobbit'>"
into m:/middle-earth/creatures});
}
close $file;
}
};
Writing your own XPath extension functions in Perl
--------------------------------------------------
XSH2 allows users to extend the set of XPath functions by providing
extension functions written in Perl. This can be achieved using the
[register-function] command. The perl code implementing an extension
function works as a usual perl routine accepting its arguments in '@_'
and returning the result. The following conventions are used:
The arguments passed to the perl implementation by the XPath engine are
simple scalars for string, boolean and float argument types and
'XML::LibXML::NodeList' objects for node-set argument types. The
implementation is responsible for checking the argument number and
types. The implementation may use general Perl functions as well as
'XML::LibXML' methods to process the arguments and return the result.
Documentation for the 'XML::LibXML' Perl module can be found for
example at http://search.cpan.org/~pajas/XML-LibXML/.
Extension functions SHOULD NOT MODIFY the document DOM tree. Doing so
could not only confuse the XPath engine but possibly even result in an
critical error (such as segmentation fault). Calling XSH2 commands from
extension function implementations is also dangerous and isn't
generally recommended.
The extension function implementation must return a single value, which
can be of one of the following types: simple scalar (a number or
string), 'XML::LibXML::Boolean' object reference (result is a boolean
value), 'XML::LibXML::Literal' object reference (result is a string),
'XML::LibXML::Number' object reference (result is a float),
'XML::LibXML::Node' (or derived) object reference (result is a node-set
consisting of a single node), or 'XML::LibXML::NodeList' (result is a
node-set). For convenience, simple (non-blessed) array references
consisting of 'XML::LibXML::Node' objects can also be used for a
node-set result instead of a 'XML::LibXML::NodeList'.
Calling the System Shell
------------------------
In the interactive mode, XSH2 interprets all lines starting with the
exclamation mark ('!') as shell commands and invokes the system shell
to interpret the line (this is to mimic FTP and similar command-line
interpreters).
Example:
xsh> !ls -l
-rw-rw-r-- 1 pajas pajas 6355 Mar 14 17:08 Artistic
drwxrwxr-x 2 pajas users 128 Sep 1 10:09 CVS
-rw-r--r-- 1 pajas pajas 14859 Aug 26 15:19 ChangeLog
-rw-r--r-- 1 pajas pajas 2220 Mar 14 17:03 INSTALL
-rw-r--r-- 1 pajas pajas 18009 Jul 15 17:35 LICENSE
-rw-rw-r-- 1 pajas pajas 417 May 9 15:16 MANIFEST
-rw-rw-r-- 1 pajas pajas 126 May 9 15:16 MANIFEST.SKIP
-rw-r--r-- 1 pajas pajas 20424 Sep 1 11:04 Makefile
-rw-r--r-- 1 pajas pajas 914 Aug 26 14:32 Makefile.PL
-rw-r--r-- 1 pajas pajas 1910 Mar 14 17:17 README
-rw-r--r-- 1 pajas pajas 438 Aug 27 13:51 TODO
drwxrwxr-x 5 pajas users 120 Jun 15 10:35 blib
drwxrwxr-x 3 pajas users 1160 Sep 1 10:09 examples
drwxrwxr-x 4 pajas users 96 Jun 15 10:35 lib
-rw-rw-r-- 1 pajas pajas 0 Sep 1 16:23 pm_to_blib
drwxrwxr-x 4 pajas users 584 Sep 1 21:18 src
drwxrwxr-x 3 pajas users 136 Sep 1 10:09 t
-rw-rw-r-- 1 pajas pajas 50 Jun 16 00:06 test
drwxrwxr-x 3 pajas users 496 Sep 1 20:18 tools
-rwxr-xr-x 1 pajas pajas 5104 Aug 30 17:08 xsh
To invoke a system shell command or program from the non-interactive
mode or from a complex XSH2 construction, use the [exec] command.
Since UNIX shell commands are very powerful tool for processing textual
data, XSH2 supports direct redirection of XSH2 commands output to
system shell command. This is very similarly to the redirection known
from UNIX shells, except that here, of course, the first command in the
pipe-line colone is an XSH2 [command]. Since semicolon (';') is used in
XSH2 to separate commands, it has to be prefixed with a backslash if it
should be used for other purposes.
Example: Use grep and less to display context of `funny'
xsh> ls //chapter[5]/para | grep funny | less
Example: The same on Windows 2000/XP systems
xsh> ls //chapter[5]/para | find "funny" | more
Related help items:
exec, hash, lcd, map, perl, rename
END
$HELP{'Prompt'}=[<<'END'];
Prompt in the interactive shell
-------------------------------
Like many other shells, XSH2 provides means for customizing the format of
its interactive shell prompt. The prompt is displayed according to the
content of the variable '$PROMPT' on which the following substitutions
and interpolations are performed (in this order):
1. Prompt-string replacements
%% - percent sign
%p - XPath location of the current node
%P - like %p but without an initial document variable
%l - XPath location of the current node with ID-shortcuts
%L - like %l but without an initial document variable
%n - name of the current node
%N - local name of the current node
%c - canonical XPath name of the current node
%y - type of the current node (element,attribute,...)
%i - ID of the current node
%d - current document variable
%h - the hostname up to the first '.'
%H - the hostname
%s - XSH shell name (basename of $0)
%t - the current time in 24-hour HH:MM:SS format
%T - the current time in 12-hour HH:MM:SS format
%@ - the current time in 12-hour am/pm format
%A - the current time in 24-hour HH:MM format
%u - the username of the current user
%v - the version of XSH2 (e.g., 2.1.0)
%V - the revision number of XML::XSH2::Functions (e.g. 2.40)
%w - current working directory (on the local filesystem)
%W - basename of %w
2. Variable, XPath and Perl interpolations
Substrings of the forms '${variable}', '${{...perl...}}' and
'${(...xpath...)}' are interpolated as in XSH2 [expressions].
3. Special character substitution
\n - newline character
\r - line-feed character
\t - tab character
\a - bell character
\b - backspace character
\f - form feed character
\e - escape character (\033)
\\ - backslash character
\nnn - the character corresponding to the octal number nnn
(useful for non-printable terminal control characters)
The default value of '$PROMPT' is '"%p>"'.
Note that you must escape '${...}' interpolators like '\${...}' if you
want them to be evaluated at each prompt rather than at the time of the
assignment to '$PROMPT'. For example:
Example: Let `uname` be computed once, `date` at every prompt
$PROMPT="[${{ chomp($u=`uname`);$u }} \${{ chomp($d=`date`);$d }}] %p>"
END
$HELP{'xsh2delta'}=[<<'END'];
Changes since XSH 1.x
---------------------
This section briefly describes differences between XSH2 and previous XSH
1.x releases. The list should not be considered complete. Some syntax
variations or amendments in the semantics of various commands may not be
documented in this section, neither are various improvements in the XSH
interpreter.
Changes in XSH2
---------------
1. In XSH2, subroutines can be called without a [call]. They can be
[redefined] and [undefined]. The command [call] can still be used,
but it's use only makes sense in indirect calls, where subroutine's
name is computed from an expression.
def foo $param1 $param2 {
# param1 and $param2 are lexical (a.k.a. my)
ls $param1;
echo $param2
}
foo (//chapter)[1] (//chapter)[1]/title
def inc $param1 { return ($param1 + 1) }
$two := inc 1;
2. XSH2 uses variables of the form [$variable] for all kinds of
objects, including node-sets (which, if evaluated as Perl
expressions, preserve node order). Node-list variables of XSH 1.x
have been deprecated.
$var = //foo/bar; # node set
$var = "hallo world"; # string
$var = xsh:new-element("foo"); # node object
$var = { ['a','b','c'] }; # Perl array reference
$var = {{ 'a'=>'A', 'b'=>'B' }}; # Perl hash reference
3. XSH2 allows variables to be used in XPath just as they are used in
XSLT:
$var = //foo/bar;
ls //baz[ . = $var[@test=1]/any ]
Variable interpolation is still available in XSH2 via ${var}, but
it's importance is diminished compared to XSH 1.x, because the XPath
engine now evaluates variables directly. Interpolation can still be
used for things like "XPath-macros":
$filter = "[ . = $var[@test=1]/any ]";
ls //baz${filter};
4. XSH2 equally supports XPath and Perl [expressions] (written in
braces { ... }). Unfortunately, Perl expressions can't be embedded in
XPath [expressions], but one can still use variables as an agent:
perl { use MIME::Base64 };
my $encoded = { encode_base64('open sesame') }
ls //secret-cave[string(password) = $encoded]
We can, however, use Perl-only expressions complemented with
auto-conversion to do things like:
copy { encode_base64('Pe do mellon a minno!') } replace //secret-cave/password/text();
5. Commands return values (see [:= assignment], or [&{ }
expressions]).
$moved_paras := xmove //para replace .;
$chapter := wrap chapter $moved_paras;
ls $chapter;
# or just
ls &{ wrap chapter &{ xmove //para replace . } };
6. XSH2 deprecates "string" expressions of XSH 1.x. However, for
convenience, some XSH2 commands interpret name-like XPath expressions
on certain argument positions as strings (mostly commands that expect
file-name or node-name arguments):
insert element my_document into .;
insert text "foo" into my_document;
$doc := open my_document; # opens file named "my_document"
$doc := open "my_document"; # same
$doc := open (my_document); # opens file named "foo"
$doc := open string(my_document); # same
7. In XSH2, XML documents have no ID. They are referred to using
variables (which fits in well with the unified variable concept):
$doc1 := open "foo1.xml";
$doc2 := open "foo2.xml";
ls ($doc1//para|$doc2//para);
cd $doc1;
ls id('intro'); # finds ID intro in the current document ($doc1)
ls xsh:id2($doc2, 'intro'); # finds ID intro in $doc2
8. XSH2 commands have options and flags instead of many optional
(positional) arguments. Options/flags usually have both long forms
(like --flag) and equivalent short forms (like :f) (colon is borrowed
from Scheme, because dash is reserved for XPath minus).
$doc := open --format html "version1.html";
save --file "version2.xml" $doc;
ls --fold /;
ls :f /;
ls --depth 1 /;
ls :d 1 /;
# all the same:
$sorted = sort --key @name --locale --descending //user;
$sorted = sort :l:d:k@name //user;
$sorted = sort --key @name --compare { use locale; $b cmp $a } //user;
validate --relaxng --file "test.rng" $mydoc;
validate --public "-//OASIS//DTD DocBook XML V4.1.2//EN" $mydoc;
validate --yesno $mydoc;
9. Finally, [eval] is no longer an alias for [perl] in XSH2, but
instead evaluates strings containing XSH2 commands (so 'eval $string'
now practically works like old ugly 'perl { xsh($string) }'). See the
documentation for [eval] for a handy usage example (no more PHP, XSTL
and XPathScript :-)).
Examples
--------
Example: Open command has changed.
XSH1:
foo = file.xml;
or
foo = "file.xml";
XSH2:
$foo := open file.xml; # file.xml is a bareword in file-name context
or
$foo := open "file.xml"; # "file.xml" is a XPath string
or
$foo := open {"file.xml"}; # "file.xml" is a Perl string
or
$foo = xsh:open("file.xml"); # righthand side is an XPath extension function
Example: XSH2 commands have options
XSH1:
open HTML FILE foo2 = "file.html";
XSH2:
$foo2 := open --format html "file.html";
Example: documents
XSH1:
foo = file.xml;
ls foo:(//bar|//baz);
XSH2:
$foo := open file.xml;
ls ($foo//bar|$foo//baz);
Example: variable interpretation
XSH1:
$family = "Arial";
ls //font[@family="$family"]; # interpolation
or
ls //font[@family="${family}"]; # interpolation
XSH2:
$family = "Arial";
ls //font[@family=$family]; # evaluation by XPath engine
or
ls //font[@family="${family}"]; # interpolation
Example: adding new nodes
XSH1:
insert attribute "foo=bar" into /scratch;
XSH2:
insert attribute "foo=bar" into /scratch;
or
copy xsh:new-attribute("foo","bar") into /scratch;
Example: foreach with perl expression
XSH1:
foreach { glob('*.xml') } {
open doc = $__;
...
}
XSH2:
foreach { glob('*.xml') } {
my $doc := open .;
...
}
Example: foreach (perl expression) with variable
XSH2:
foreach my $filename in { glob('*.xml') } {
my $doc := open $filename;
...
}
Example: sorting nodes
XSH1:
%list = //player;
sort @best_score { $a <=> $b } %list;
copy %list into .;
XSH2:
$list := sort --numeric --key @best_score //player;
copy { $list } into .;
or
copy &{ sort --numeric --key @best_score //player } into .;
or (using short options)
copy &{ sort :n :k @best_score //player } into .;
END
$HELP{'commands'}=$HELP{'command'};
$Apropos = {
'xsh:lc' => undef,
'quiet' => 'turn off many XSH2 messages',
'canonical' => 'serialize nodes as to canonical XML',
'xsh:matches' => undef,
'create' => 'make a new document from a given XML fragment',
'xpath-extensions' => 'map predefined XSH2 XPath extension functions to no or other namespace',
'documents' => 'display a list of open documents',
'xsh:times' => undef,
'location' => 'relative destination specification (such as after, before, etc.)',
'xsh:span' => undef,
'nodebug' => 'turn off debugging messages',
'map' => 'transform node value/data using Perl or XPath expression',
'xpath' => 'XPath expression',
'parser-completes-attributes' => 'turn on/off parser\'s ability to fill default attribute values',
'remove' => 'remove given nodes',
'variables' => 'list global variables',
'validate' => 'validate a document against a DTD, RelaxNG, or XSD schemas',
'xsh:ucfirst' => undef,
'xsh:same' => undef,
'ifinclude' => 'conditionally include another XSH2 source in current position',
'change-ns-prefix' => 'change namespace prefix (EXPERIMENTAL)',
'run-mode' => 'switch into normal execution mode (quit [test-mode])',
'xsh:subst' => undef,
'query-encoding' => 'declare the charset of XSH2 source files and terminal input',
'locate' => 'show a given node location (as a canonical XPath)',
'index' => 'index a static document for faster XPath lookup',
'edit' => 'Edit parts of a XML document in a text editor.',
'xsh:new-comment' => undef,
'edit-string' => 'Edit a string or variable in a text editor.',
'wrap-span' => 'wrap spans of nodes into elements',
'ls' => 'list a given part of a document as XML',
'iterate' => 'iterate a block over current subtree',
'parser-expands-xinclude' => 'turn on/off transparent XInclude insertion by parser',
'nodename' => 'specifying names of DOM nodes',
'exec' => 'execute a shell command',
'open' => 'load an XML, HTML, or Docbook SGML document from a file, pipe or URI',
'empty-tags' => 'turn on/off serialization of empty tags',
'namespaces' => 'List namespaces available in a context of a given nodes',
'register-function' => 'define XPath extension function (EXPERIMENTAL)',
'skip-dtd' => 'turn on/off serialization of DTD DOCTYPE declaration',
'xpath-axis-completion' => 'sets TAB completion for axes in xpath expressions in the interactive mode',
'unless' => 'negated if statement',
'set-dtd' => 'set document\'s DTD declaration',
'rename' => 'quickly rename nodes with in-line Perl code',
'xsh:doc' => undef,
'backups' => 'turn on backup file creation',
'doc-info' => 'displays various information about a document',
'node-type' => 'node type specification (such as element, attribute, etc.)',
'xsh:map' => undef,
'xsh:new-element-ns' => undef,
'xsh:sum' => undef,
'process-xinclude' => 'load and insert XInclude sections',
'do' => 'execute a given block of commands',
'xinsert' => 'create nodes on all target locations',
'xsh:documents' => undef,
'register-xsh-namespace' => 'register a prefix for the XSH2 namespace',
'apropos' => 'search the documentation',
'verbose' => 'make XSH2 print many messages',
'xsh:new-cdata' => undef,
'xsh:parse' => undef,
'filename' => 'specifying filenames',
'unregister-namespace' => 'unregister namespace prefix',
'throw' => 'throw an exception',
'xsh:new-text' => undef,
'nobackups' => 'turn off backup file creation',
'parser-expands-entities' => 'turn on/off parser\'s tendency to expand entities',
'set-enc' => 'set document\'s charset (encoding)',
'while' => 'simple while loop',
'try' => 'try/catch statement',
'clone' => 'clone a given document',
'save' => 'save a document as XML or HTML',
'version' => 'show version information',
'xsh:split' => undef,
'xsh:evaluate' => undef,
'perl' => 'evaluate in-line Perl code',
'xsh:match' => undef,
'cd' => 'change current context node',
'redo' => 'restart the innermost enclosing loop block',
'defs' => 'list all user-defined subroutines',
'xsh:filename' => undef,
'perl-code' => 'in-line code in Perl programming language',
'foreach' => 'loop iterating over a node-list or a perl array',
'xsh:strmax' => undef,
'xsh:reverse' => undef,
'print' => 'print stuff on standard or standard error output',
'type' => undef,
'xsh:sprintf' => undef,
'lcd' => 'change system working directory',
'xsh:new-attribute' => undef,
'document' => 'specifying documents',
'subroutine' => 'name of a sub-routine',
'unfold' => 'unfold elements folded with fold command',
'eval' => 'evaluate given expression as XSH commands',
'xpath-completion' => 'turn on/off TAB completion for xpath expressions in the interactive mode',
'xsh:document-uri' => undef,
'assign' => 'variable assignment',
'call' => 'indirect call to a user-defined routine (macro)',
'help' => 'on-line documentation',
'my' => 'Create a new lexically scoped variable',
'strip-whitespace' => 'strip leading and trailing whitespace',
'set_filename' => 'change filename or URL associated with a document',
'stream' => 'process selected elements from an XML stream (EXPERIMENTAL)',
'block' => 'a block of XSH2 commands',
'register-xhtml-namespace' => 'register a prefix for the XHTML namespace',
'xsh:current' => undef,
'last' => 'immediately exit an enclosing loop',
'xsh:new-chunk' => undef,
'xsh:base-uri' => undef,
'pwd' => 'show current context node location (as a canonical XPath)',
'move' => 'move nodes (in the one-to-one mode)',
'xsh:new-element' => undef,
'pedantic-parser' => 'make the parser more pedantic',
'xsh:uc' => undef,
'xsh:lookup' => undef,
'settings' => 'list current settings using XSH2 syntax',
'xmove' => 'move nodes (in the all-to-every mode)',
'insert' => 'create a node in on a given target location',
'expression' => 'expression argument type',
'declare-ns' => 'create a special attribute declaring an XML namespace (EXPERIMENTAL)',
'wrap' => 'wrap given nodes into elements',
'test-mode' => 'do not execute any command, only check the syntax',
'include' => 'include another XSH2 source in current position',
'xsh:min' => undef,
'xsh:new-pi' => undef,
'enc' => 'show document\'s original character encoding',
'normalize' => 'normalizes adjacent textnodes',
'copy' => 'copy nodes (in the one-to-one mode)',
'load-ext-dtd' => 'turn on/off external DTD fetching',
'return' => 'return from a subroutine',
'xsh:id2' => undef,
'encoding' => 'choose output charset',
'validation' => 'turn on/off validation in XML parser',
'lineno' => 'print line-numbers corresponding to matching nodes',
'dtd' => 'show document\'s DTD',
'xsh:var' => undef,
'set' => 'create or modify document content (EXPERIMENTAL)',
'xsh:serialize' => undef,
'fold' => 'mark elements to be folded by list command',
'close' => 'close document (without saving)',
'xsh:substr' => undef,
'recovering' => 'turn on/off parser\'s ability to fix broken XML',
'xupdate' => 'apply XUpdate commands on a document',
'switch-to-new-documents' => 'set on/off changing current document to newly open/created files',
'xsh:max' => undef,
'hash' => 'index selected nodes by some key value',
'sort' => 'sort a given node-list by given criteria',
'xsh:context' => undef,
'xsh:strmin' => undef,
'catalog' => 'use a catalog file during all parsing processes',
'change-ns-uri' => 'change namespace URI (EXPERIMENTAL)',
'unregister-function' => 'undefine extension function (EXPERIMENTAL)',
'xsh:document' => undef,
'xsh:lcfirst' => undef,
'xsh:resolve-uri' => undef,
'indent' => 'turn on/off pretty-printing',
'exit' => 'exit XSH2 shell',
'xslt' => 'compile a XSLT stylesheet and/or transform a document with XSLT',
'get' => 'calculate a given expression and return the result.',
'count' => 'calculate a [expression] and enumerate node-lists',
'xsh:path' => undef,
'set-standalone' => 'set document\'s standalone flag',
'def' => 'sub-routine declaration',
'xsh:lineno' => undef,
'$variable' => undef,
'prev' => 'restart an iteration on a previous node',
'xsh:join' => undef,
'undef' => 'undefine sub-routine or variable',
'command' => 'List of XSH2 commands and their general syntax',
'xsh:grep' => undef,
'next' => 'start the next iteration of an enclosing loop',
'xsh:if' => undef,
'local' => 'temporarily assign new value to a variable',
'if' => 'if statement',
'xcopy' => 'copy nodes (in the all-to-every mode)',
'debug' => 'display many annoying debugging messages',
'keep-blanks' => 'turn on/off ignorable whitespace preservation',
'register-namespace' => 'register namespace prefix to use XPath expressions',
'set-ns' => 'set namespace of the current node (EXPERIMENTAL)'
};
1;
__END__