Sub::HandlesVia::HandlerLibrary::Code(3) User Contributed Perl Documentation Sub::HandlesVia::HandlerLibrary::Code(3)

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

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',
    },
  );
}

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

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 );

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

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 );

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

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

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

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

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

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

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

Sub::HandlesVia.

Toby Inkster <tobyink@cpan.org>.

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.

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.

2024-09-02 perl v5.40.0