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Postings from January 2021
On Tue, Jan 12, 2021, at 4:11 PM, Eric Wong wrote:
> Uri Guttman <uri@stemsystems.com> wrote:
> > i wonder why he copies %ENV. he should be able to just do:
> >
> > local( $SIG{$signame} ) = blah ;
> >
> > the is faster and doesn't have the odd number thing you mention
>
> Laziness :) I'm getting a hash(ref) of SIG overrides either as
> a return value from another sub. My workaround is something
> like this:
>
> my %sig = $self->some_callback;
> local $SIG{$_} = $sig->{$_} for keys %sig;
"something like" can cover a lot of ground here, but are you sure that your workaround isn't so close to this that, like this, it just doesn't work?
X for Y is equivalent to "for (Y) { X }" including the enclosing scope, which delimits the effect of local.
use v5.30.0;
use Data::Dumper;
our %hash = (a => 1, b => 1);
{
local $hash{$_} = 2 for keys %hash;
print Dumper(\%hash);
}
{
local %hash = %hash;
$hash{$_} = 2 for keys %hash;
print Dumper(\%hash);
}
print Dumper(\%hash);
…which outputs…
$VAR1 = {
'a' => 1,
'b' => 1
};
$VAR1 = {
'a' => 2,
'b' => 2
};
$VAR1 = {
'a' => 1,
'b' => 1
};
--
rjbs
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