Sub::HandlesVia::HandlerLibrary::Code(3p)

NAME
Sub::HandlesVia::HandlerLibrary::Code - library of code-related methods

SYNOPSIS
  package My::Class {
    use Moo;
    use Sub::HandlesVia;
    use Types::Standard 'CodeRef';
    has attr => (
      is => 'rwp',
      isa => CodeRef,
      handles_via => 'Code',
      handles => {
        'my_execute' => 'execute',
        'my_execute_list' => 'execute_list',
        'my_execute_method' => 'execute_method',
        'my_execute_method_list' => 'execute_method_list',
        'my_execute_method_scalar' => 'execute_method_scalar',
        'my_execute_method_void' => 'execute_method_void',
        'my_execute_scalar' => 'execute_scalar',
        'my_execute_void' => 'execute_void',
      },
    );
  }

DESCRIPTION
This is a library of methods for Sub::HandlesVia.

DELEGATABLE METHODS

  execute( @args )
Calls the coderef, passing it any arguments.

  my $coderef = sub { 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( 1, 2, 3 )
  $object->my_execute( 1, 2, 3 );

  execute_list( @args )
Calls the coderef, passing it any arguments, and forcing list context. If called in scalar context, returns an arrayref.

  my $context;
  my $coderef = sub { $context = wantarray(); 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( 1, 2, 3 )
  my $result = $object->my_execute_list( 1, 2, 3 );

  say Dumper( $result );  ## ==> [ 'code' ]
  say $context;           ## ==> true

  execute_method( @args )
Calls the coderef as if it were a method, passing any arguments.

  my $coderef = sub { 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( $object, 1, 2, 3 )
  $object->my_execute_method( 1, 2, 3 );

  execute_method_list( @args )
Calls the coderef as if it were a method, passing any arguments, and forcing list context. If called in scalar context, returns an arrayref.

  my $context;
  my $coderef = sub { $context = wantarray(); 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( $object, 1, 2, 3 )
  my $result = $object->my_execute_method_list( 1, 2, 3 );

  say Dumper( $result );  ## ==> [ 'code' ]
  say $context;           ## ==> true

  execute_method_scalar( @args )
Calls the coderef as if it were a method, passing any arguments, and forcing scalar context.

  my $context;
  my $coderef = sub { $context = wantarray(); 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( $object, 1, 2, 3 )
  my $result = $object->my_execute_method_scalar( 1, 2, 3 );

  say $result;  ## ==> 'code'
  say $context; ## ==> false

  execute_method_void( @args )
Calls the coderef as if it were a method, passing any arguments, and forcing void context. Returns undef.

  my $context;
  my $coderef = sub { $context = wantarray(); 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( $object, 1, 2, 3 )
  my $result = $object->my_execute_method_void( 1, 2, 3 );

  say $result;  ## ==> undef
  say $context; ## ==> undef

  execute_scalar( @args )
Calls the coderef, passing it any arguments, and forcing scalar context.

  my $context;
  my $coderef = sub { $context = wantarray(); 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( 1, 2, 3 )
  my $result = $object->my_execute_scalar( 1, 2, 3 );

  say $result;  ## ==> 'code'
  say $context; ## ==> false

  execute_void( @args )
Calls the coderef, passing it any arguments, and forcing void context. Returns undef.

  my $context;
  my $coderef = sub { $context = wantarray(); 'code' };
  my $object  = My::Class->new( attr => $coderef );

  # Calls: $coderef->( 1, 2, 3 )
  my $result = $object->my_execute_void( 1, 2, 3 );

  say $result;  ## ==> undef
  say $context; ## ==> undef

EXTENDED EXAMPLES

  Using execute_method
The execute_method handler allows a class to effectively provide certain methods which can be overridden by parameters in the constructor.

  use strict;
  use warnings;
  use Data::Dumper;

  package My::Processor {
    use Moo;
    use Sub::HandlesVia;
    use Types::Standard qw( Str CodeRef );

    has name => (
      is => 'ro',
      isa => Str,
      default => 'Main Process',
    );

    my $NULL_CODEREF = sub {};

    has _debug => (
      is => 'ro',
      isa => CodeRef,
      handles_via => 'Code',
      handles => { debug => 'execute_method' },
      default => sub { $NULL_CODEREF },
      init_arg => 'debug',
    );

    sub _do_stuff {
      my $self = shift;
      $self->debug( 'continuing process' );
      return;
    }

    sub run_process {
      my $self = shift;
      $self->debug( 'starting process' );
      $self->_do_stuff;
      $self->debug( 'ending process' );
    }
  }

  my $p1 = My::Processor->new( name => 'First Process' );
  $p1->run_process; # no output

  my @got;
  my $p2 = My::Processor->new(
    name => 'Second Process',
    debug => sub {
      my ( $processor, $message ) = @_;
      push @got, sprintf( '%s: %s', $processor->name, $message );
    },
  );
  $p2->run_process; # logged output

  my @expected = (
    'Second Process: starting process',
    'Second Process: continuing process',
    'Second Process: ending process',
  );
  say Dumper( \@got ); ## ==> \@expected

BUGS
Please report any bugs to <https://github.com/tobyink/p5-sub-handlesvia/issues>.

SEE ALSO
Sub::HandlesVia.

AUTHOR
Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE
This software is copyright (c) 2020, 2022 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.