Class::MethodMaker::scalar(3)              User Contributed Perl Documentation


NAME
       Class::Method::scalar - Create methods for handling a scalar value.

SYNOPSIS
         package MyClass;
         use Class::MethodMaker
           [ scalar => [qw/ a -static s /]];

         sub new {
           my $class = shift;
           bless {}, $class;
         }

         package main;

         my $m = MyClass->new;
         my $a, $x;

         $a = $m->a;       # *undef*
         $x = $m->a_isset; # false
         $a = $m->a(1);    # 1
         $m->a(3);
         $x = $m->a_isset; # true
         $a = $m->a;       # 3
         $a = $m->a(5);     # 5;
         $m->a_reset;
         $x = $m->a_isset; # false

DESCRIPTION
       Creates methods to handle array values in an object.  For a component
       named "x", by default creates methods "x", "x_reset", "x_isset",
       "x_clear".

       Methods available are:

       "*"

         $m->a(3);
         $a = $m->a;       # 3
         $a = $m->a(5);     # 5;

       Created by default.  If an argument is provided, the component is set
       to that value.  The method returns the value of the component (after
       assignment to a provided value, if appropriate).

       *_reset

         $m->a_reset;

       Created by default.  Resets the component back to its default.
       Normally, this means that *_isset will return false, and "*" will
       return undef.  If "-default" is in effect, then the component will be
       set to the default value, and *_isset will return true.  If
       "-default_ctor" is in effect, then the default subr will be invoked,
       and its return value used to set the value of the component, and
       *_isset will return true.

       Advanced Note: actually, defaults are assigned as needed: typically,
       the next time a the value of a component is read.

       *_isset

         print $m->a_isset ? "true" : "false";

       Created by default.  Whether the component is currently set.  This is
       different from being defined; initially, the component is not set (and
       if read, will return undef); it can be set to undef (which is a set
       value, which also returns undef).  Having been set, the only way to
       unset the component is with <*_reset>.

       If a default value is in effect, then <*_isset> will always return
       true.

       *_clear

         $m->a(5);
         $a = $m->a;       # 5
         $x = $m->a_isset; # true
         $m->a_clear;
         $a = $m->a;       # *undef*
         $x = $m->a_isset; # true

       Created by default.  A shorthand for setting to undef.  Note that the
       component will be set to undef, not reset, so *_isset will return true.

       *_get

         package MyClass;
         use Class::MethodMaker
           [ scalar => [{'*_get' => '*_get'}, 'a'],
             new    => new, ];

         package main;
         my $m = MyClass->new;
         $m->a(3);
         $a = $m->a_get;     # 3
         $a = $m->a_get(5);  # 3; ignores argument
         $a = $m->a_get(5);  # 3; unchanged by previous call

       Created on request.  Retrieves the value of the component without
       setting (ignores any arguments passed).

       *_set

         package MyClass;
         use Class::MethodMaker
           [ scalar => [{'*_set' => '*_set'}, 'a'],
             new    => new, ];

         package main;
         my $m = MyClass->new;
         $m->a(3);
         $a = $m->a_set;     # *undef*
         $a = $m->a_set(5);  # *undef*; value is set but not returned
         $a = $m->a;         # 5

       Created on request.  Sets the component to the first argument (or undef
       if no argument provided).  Returns no value.

perl v5.38.0                      2023-07-25     Class::MethodMaker::scalar(3)