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This is the first time I see a modifier modifying a method defined in the same class. I've always used modifiers with inheritance or roles, modifying a parent or required method. Nevertheless, you can't wrap a trigger coming from a parent class, either.

That's because the trigger is defined as a code reference, not as a sub name. It means you can modify e.g. a predicate, because it's defined by name, because modifiers redefine a method of the given name.

I see two ways how to wrap a trigger in a more Moosey way: either define a new trigger in the overridden attribute, or define the trigger as a sub that calls a method that you later modify (predicate overriding shown in the example, too):

#!/usr/bin/perl use warnings; use strict; use feature qw{ say }; { package My; use Moose; has a1 => ( is => 'rw', trigger => \&a1_changed, predicate => 'has_attr' ); has a2 => ( is => 'rw', trigger => sub { $_[0]->a2_changed(@_[ 1 .. $#_ ]) } ) +; sub a1_changed { print ref shift, ": a1 changed.\n"; } sub a2_changed { print ref shift, ": a2 changed.\n"; } __PACKAGE__->meta->make_immutable; no Moose; } { package My::Child; use Moose; extends 'My'; has '+a1' => ( trigger => \&a1_changed ); sub a1_changed { print "Trigger 1 wrapped.\n"; $_[0]->SUPER::a1_changed; }; around a2_changed => sub { print "Trigger 2 wrapped\n"; $_[0]->(@_[ 1 .. $#_ ]); }; around has_attr => sub { print "Predicate wrapped\n"; }; __PACKAGE__->meta->make_immutable; no Moose; } my $o = 'My'->new; my $ch = 'My::Child'->new; $o->a1(2); $ch->a1(2); say $o->has_attr; say $ch->has_attr; $o->a2(3); $ch->a2(3);

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord }map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

In reply to Re: Moose triggers & method modifiers by choroba
in thread Moose triggers & method modifiers by bobf

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