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Re^4: Declaring with my, assigning, and testing in same line (attributes)

by choroba (Cardinal)
on Dec 12, 2015 at 21:58 UTC ( [id://1150139]=note: print w/replies, xml ) Need Help??


in reply to Re^3: Declaring with my, assigning, and testing in same line (attributes)
in thread Declaring with my, assigning, and testing in same line

You can tie in the attribute handler, so you can untie there, too. So, a closure sent as an extra argument to the constructor works:
#!/usr/bin/perl use warnings; use strict; use feature qw{ say }; { package Array::Nonempty::Attr; use Attribute::Handlers; sub Nonempty :ATTR(ARRAY) { my $referer = $_[2]; tie @$referer, 'Array::Nonempty', sub { untie @$referer } } } { package Array::Nonempty; use Tie::Array; use parent -norequire => 'Tie::StdArray'; use Carp; sub CLEAR { my $self = shift; $self->[0] = []; } sub TIEARRAY { my ($class, $untie) = @_; bless [ [], $untie ], $class } sub EXTEND { my ($self, $size) = @_; croak "Cannot be empty" if 0 == @{ $self->[0] } && 0 == $size; $self->SUPER::EXTEND($size); # Prevent "untie attempted while 1 inner references still exis +t" my $untie = $self->[1]; undef $self; $untie->() } } use parent -norequire => 'Array::Nonempty::Attr'; my %hash_ok = ( answer => 42 ); my %hash_empty = (); my @keys_ok :Nonempty = keys %hash_ok; say tied(@keys_ok) // 'not tied'; say for @keys_ok; my @keys_empty :Nonempty = keys %hash_empty;
($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,

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Re^5: Declaring with my, assigning, and testing in same line (attributes)
by LanX (Saint) on Dec 12, 2015 at 22:05 UTC
    nice! :)

    see

    use Attribute::Handlers autotieref => { Selfish => Tie::Selfish };

    for another way for untie to access the varref

    Cheers Rolf
    (addicted to the Perl Programming Language and ☆☆☆☆ :)
    Je suis Charlie!

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