NAME

Type::Tiny::Manual::NonOO - Type::Tiny in non-object-oriented code

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 Type::Tiny::Manual::UsingWithMoo, you should understand how Type::Params can be used to validate method parametters. This same technique can be applied to regular subs too; just don't shift off $self. More information about checking parameters can be found in Type::Tiny::Manual::Params.

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

Type::Tiny and Smart Match

Perl 5.10 introduced the smart match operator ~~, 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 $value is an object and overloads ~~. Which overload of ~~ 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 $value matches any type that can be coerced to SomeType.

But better to use:

  SomeType->coercion->has_coercion_for_value( $value )

given and when

Related to the smart match operator is the given/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.

NEXT STEPS

Here's your next step:

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This software is copyright (c) 2013-2014, 2017-2019 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.

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.