Created
December 10, 2021 16:14
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Raku version of classic observer pattern example but without a fixed interface.
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#!/usr/bin/env raku | |
role ObserverSignal { | |
} | |
multi sub trait_mod:<is> ( Method $m, :$observer-signal! ) { | |
$m does ObserverSignal; | |
} | |
role Observable { | |
has @.observers; | |
method signal() { | |
for @.observers -> $observer { | |
for $observer.^methods.grep(ObserverSignal).grep(*.cando(\($observer, self))) -> $method { | |
$observer.$method(self); | |
} | |
} | |
} | |
} | |
class Subject is Observable { | |
} | |
class Observer { | |
method any-old-name(Subject $) is observer-signal { | |
say "got Subject signal"; | |
} | |
} | |
my $subject = Subject.new; | |
$subject.observers.push: Observer.new; | |
$subject.signal; | |
# vim: ft=raku |
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