either the $k or the $closure method work
Be careful! Whilst the for my $name... works, it is dangerous:
my @names = qw[ the quick brown fox ];
undef %h;
for my $alias ( @names ){
$h{ $alias } = sub {
print $alias;
$alias = 'fred'; ####### Mysterious action at a distance
+here
};
};
pp \%h;
{
brown => sub { "???" },
fox => sub { "???" },
quick => sub { "???" },
the => sub { "???" },
}
for my $key ( keys %h ) { $h{ $key }->(); };;
the
fox
brown
quick
print @names;;
fred fred fred fred
With the for my $name ( ... ) method, the closures are and remain aliases to the source list in the for loop; which means that if you assign to the closure within the subroutine, you will cause spooky action at a distance to the content of that source.
And perhaps worse, changes to the source of the for list, will remotely change the contents of the closures:
[0]{} Perl>
my @names = qw[ the quick brown fox ];
undef %h;
for my $alias ( @names ){
$h{ $alias } = sub {
print $alias;
};
};
pp \%h;
{
brown => sub { "???" },
fox => sub { "???" },
quick => sub { "???" },
the => sub { "???" },
}
$names[ 1 ] .= 'Mysterious changes'; ###### And again here!
for my $key ( keys %h ) { $h{ $key }->(); };;
the
fox
brown
quickMysterious changes
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
In the absence of evidence, opinion is indistinguishable from prejudice.
Not understood.
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