1MooseX::SingleArg(3pm)User Contributed Perl DocumentationMooseX::SingleArg(3pm)
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NAME

6       MooseX::SingleArg - No-fuss instantiation of Moose objects using a
7       single argument.
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SYNOPSIS

10           package Person;
11           use Moose;
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13           use MooseX::SingleArg;
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15           single_arg 'name';
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17           has name => ( is=>'ro', isa=>'Str' );
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19           my $john = Person->new( 'John Doe' );
20           print $john->name();
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DESCRIPTION

23       This module allows Moose instances to be constructed with a single
24       argument.  Your class or role must use this module and then use the
25       single_arg sugar to declare which attribute will be assigned the single
26       argument value.
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28       If the class is constructed using the typical argument list name/value
29       pairs, or with a hashref, then things work as is usual.  But, if the
30       arguments are a single non-hashref value then that argument will be
31       assigned to whatever attribute you have declared.
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33       The reason for this module's existence is that when people want this
34       feature they usually find
35       Moose::Cookbook::Basics::Person_BUILDARGSAndBUILD which asks that
36       something like the following be written:
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38           around BUILDARGS => sub {
39               my $orig = shift;
40               my $class = shift;
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42               if ( @_ == 1 && ! ref $_[0] ) {
43                   return $class->$orig(ssn => $_[0]);
44               }
45               else {
46                   return $class->$orig(@_);
47               }
48           };
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50       The above is complex boilerplate for a simple feature.  This module
51       aims to make it simple and fool-proof to support single-argument Moose
52       object construction.
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INIT_ARG BEHAVIOR

55       If setting a custom init_arg for an attribute which you will be
56       assigning as the single_arg then use the init_arg value, rather than
57       the attribute key, for it.  For example:
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59           single_arg 'moniker';
60           has name => ( is=>'ro', isa=>'Str', init_arg=>'moniker' );
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FORCING SINGLE ARG PROCESSING

63       An optional force parameter may be specified:
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65           single_arg name => (
66               force => 1,
67           );
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69       This causes constructor argument processing to only work in single-
70       argument mode.  If more than one argument is passed then an error will
71       be thrown.  The benefit of forcing single argument processing is that
72       hashrefs may now be used as the value of the single argument when force
73       is on.
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SEE ALSO

76       MooseX::OneArgNew solves the same problem that this module solves.  I
77       considered using OneArgNew for my own needs, but found it oddly
78       cumbersome and confusing.  Maybe that's just me, but I hope that this
79       module's design is much simpler to comprehend and more natural to use.
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AUTHOR

82       Aran Clary Deltac <bluefeet@gmail.com>
83

CONTRIBUTORS

85       •   Xavier Guimard <x.guimard@free.fr>
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87       •   Mohammad S Anwar <mohammad.anwar@yahoo.com>
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LICENSE

90       This is free software; you can redistribute it and/or modify it under
91       the same terms as the Perl 5 programming language system itself.
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95perl v5.32.1                      2021-01-27            MooseX::SingleArg(3pm)
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