CPAN::Groonga

=pod

=encoding utf-8

=head1 NAME

Type::Tiny::Manual::NonOO - Type::Tiny in non-object-oriented code
  
=head1 MANUAL

Although Type::Tiny was designed with object-oriented programming in mind,
especially Moose-style classes and roles, it can be used in procedural and
imperative programming.

If you have read L<Type::Tiny::Manual::UsingWithMoo>, you should understand
how L<Type::Params> can be used to validate method parameters. This same
technique can be applied to regular subs too. More information about checking
parameters can be found in L<Type::Tiny::Manual::Params>.

The C<< is_* >> and C<< assert_* >> functions exported by type libraries
may be useful in non-OO code too. See L<Type::Tiny::Manual::UsingWithMoo3>.

=head2 Type::Tiny and Smart Match

Perl 5.10 introduced the smart match operator C<< ~~ >>, which has since
been deprecated because though the general idea is fairly sound, the details
were a bit messy.

Nevertheless, Type::Tiny has support for smart match and I'm documenting
it here because there's nowhere better to put it.

The following can be used as to check if a value passes a type constraint:

  $value ~~ SomeType

Where it gets weird is if C<< $value >> is an object and overloads C<< ~~ >>.
Which overload of C<< ~~ >> wins? I don't know.

Better to use:

  SomeType->check( $value )   # more reliable, probably faster
  is_SomeType($value)         # more reliable, definitely faster

It's also possible to do:

  $value ~~ SomeType->coercion

This checks to see if C<< $value >> matches any type that can be coerced
to B<SomeType>.

But better to use:

  SomeType->coercion->has_coercion_for_value( $value )

=head2 C<given> and C<when>

Related to the smart match operator is the C<given>/C<when> syntax.

This will not do what you want it to do:

  use Types::Standard qw( Str Int );
  
  given ($value) {
    when (Int) { ... }
    when (Str) { ... }
  }

This will do what you wanted:

  use Types::Standard qw( is_Str is_Int );
  
  given ($value) {
    when (\&is_Int) { ... }
    when (\&is_Str) { ... }
  }

Sorry, that's just how Perl be.

Better though:

  use Types::Standard qw( Str Int );
  use Type::Utils qw( match_on_type );
  
  match_on_type $value => (
    Str, sub { ... },
    Int, sub { ... },
  );

If this is part of a loop or other frequently called bit of code, you can
compile the checks once and use them many times:

  use Types::Standard qw( Str Int );
  use Type::Utils qw( compile_match_on_type );
  
  my $dispatch_table = compile_match_on_type(
    Str, sub { ... },
    Int, sub { ... },
  );
  
  $dispatch_table->($_) for @lots_of_values;

As with most things in Type::Tiny, those coderefs can be replaced by strings
of Perl code.

=head1 NEXT STEPS

Here's your next step:

=over

=item * L<Type::Tiny::Manual::Optimization>

Squeeze the most out of your CPU.

=back

=head1 AUTHOR

Toby Inkster E<lt>tobyink@cpan.orgE<gt>.

=head1 COPYRIGHT AND LICENCE

This software is copyright (c) 2013-2014, 2017-2023 by Toby Inkster.

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 DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

=cut