Data-Unixish/lib/Data/Unixish/chain.pm
package Data::Unixish::chain;
use 5.010;
use locale;
use strict;
use syntax 'each_on_array'; # to support perl < 5.12
use warnings;
#use Log::Any '$log';
use Data::Unixish::Util qw(%common_args);
our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2025-02-24'; # DATE
our $DIST = 'Data-Unixish'; # DIST
our $VERSION = '1.574'; # VERSION
our %SPEC;
$SPEC{chain} = {
v => 1.1,
summary => 'Chain several dux functions together',
description => <<'MARKDOWN',
Currently works for itemfunc only.
See also the <pm:Data::Unixish::Apply> function, which is related.
MARKDOWN
args => {
%common_args,
functions => {
summary => 'The functions to chain',
schema => ['array*' => of => ['any*', of => [
'str*',
['array*', min_len=>1, elems=>['str*','hash*']],
]]],
description => <<'MARKDOWN',
Each element must either be function name (like `date`) or a 2-element array
containing the function name and its arguments (like `[bool, {style: dot}]`).
MARKDOWN
req => 1,
pos => 0,
greedy => 1,
cmdline_aliases => {f => {}},
},
},
tags => [qw/itemfunc func/],
};
sub chain {
my %args = @_;
my ($in, $out) = ($args{in}, $args{out});
_chain_begin(\%args);
local ($., $_);
while (($., $_) = each @$in) {
push @$out, _chain_item($_, \%args);
}
[200, "OK"];
}
sub _chain_begin {
no strict 'refs'; ## no critic: TestingAndDebugging::ProhibitNoStrict
my $args = shift;
my $ff = [];
for my $f (@{ $args->{functions} }) {
my ($fn, $args);
if (ref($f) eq 'ARRAY') {
$fn = $f->[0];;
$args = $f->[1];
} else {
$fn = $f;
$args = {};
}
unless ($fn =~
/\A[A-Za-z_][A-Za-z0-9_]*(::[A-Za-z_][A-Za-z0-9_]*)*\z/) {
die "Invalid function name $fn, please use letter+alphanums only";
}
my $mod = "Data::Unixish::$fn";
unless (eval "require $mod") { ## no critic: BuiltinFunctions::ProhibitStringyEval
die "Can't load dux function $fn: $@";
}
my $fnleaf = $fn; $fnleaf =~ s/.+:://;
if (defined &{"$mod\::_${fnleaf}_begin"}) {
my $begin = \&{"$mod\::_${fnleaf}_begin"};
$begin->($args);
}
push @$ff, [$mod, $fn, $fnleaf, \&{"$mod\::_${fnleaf}_item"}, $args];
}
# abuse to store state
$args->{-functions} = $ff;
}
sub _chain_item {
my ($item, $args) = @_;
local $_ = $item;
for my $f (@{ $args->{-functions} }) {
$item = $f->[3]->($item, $f->[4]);
}
$item;
}
sub _chain_end {
no strict 'refs'; ## no critic: TestingAndDebugging::ProhibitNoStrict
my $args = shift;
for my $f (@{ $args->{-functions} }) {
my $mod = $f->[0];
my $fnleaf = $f->[2];
my $args = $f->[4];
if (defined &{"$mod\::_${fnleaf}_end"}) {
my $end = \&{"$mod\::_${fnleaf}_end"};
$end->($args);
}
}
}
1;
# ABSTRACT: Chain several dux functions together
__END__
=pod
=encoding UTF-8
=head1 NAME
Data::Unixish::chain - Chain several dux functions together
=head1 VERSION
This document describes version 1.574 of Data::Unixish::chain (from Perl distribution Data-Unixish), released on 2025-02-24.
=head1 SYNOPSIS
In Perl:
use Data::Unixish qw(lduxl);
my @res = lduxl([chain => {functions => ['date', ["ANSI::color" => {color=>"yellow"}]]}], 1000, 2000);
In command-line:
% echo -e "1000\n2000" | dux chain --functions-json '["date", ["ANSI::color",{"color":"yellow"}]]'
2
3
4
=head1 FUNCTIONS
=head2 chain
Usage:
chain(%args) -> [$status_code, $reason, $payload, \%result_meta]
Chain several dux functions together.
Currently works for itemfunc only.
See also the L<Data::Unixish::Apply> function, which is related.
This function is not exported.
Arguments ('*' denotes required arguments):
=over 4
=item * B<functions>* => I<array[str|array]>
The functions to chain.
Each element must either be function name (like C<date>) or a 2-element array
containing the function name and its arguments (like C<[bool, {style: dot}]>).
=item * B<in> => I<array>
Input stream (e.g. array or filehandle).
=item * B<out> => I<any>
Output stream (e.g. array or filehandle).
=back
Returns an enveloped result (an array).
First element ($status_code) is an integer containing HTTP-like status code
(200 means OK, 4xx caller error, 5xx function error). Second element
($reason) is a string containing error message, or something like "OK" if status is
200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth
element (%result_meta) is called result metadata and is optional, a hash
that contains extra information, much like how HTTP response headers provide additional metadata.
Return value: (any)
=head1 HOMEPAGE
Please visit the project's homepage at L<https://metacpan.org/release/Data-Unixish>.
=head1 SOURCE
Source repository is at L<https://github.com/perlancar/perl-Data-Unixish>.
=head1 AUTHOR
perlancar <perlancar@cpan.org>
=head1 CONTRIBUTING
To contribute, you can send patches by email/via RT, or send pull requests on
GitHub.
Most of the time, you don't need to build the distribution yourself. You can
simply modify the code, then test via:
% prove -l
If you want to build the distribution (e.g. to try to install it locally on your
system), you can install L<Dist::Zilla>,
L<Dist::Zilla::PluginBundle::Author::PERLANCAR>,
L<Pod::Weaver::PluginBundle::Author::PERLANCAR>, and sometimes one or two other
Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond
that are considered a bug and can be reported to me.
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2025 by perlancar <perlancar@cpan.org>.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=head1 BUGS
Please report any bugs or feature requests on the bugtracker website L<https://rt.cpan.org/Public/Dist/Display.html?Name=Data-Unixish>
When submitting a bug or request, please include a test-file or a
patch to an existing test-file that illustrates the bug or desired
feature.
=cut