Hi Charles,
On Sunday 14 November 2010 01:47:36 C.DeRykus wrote:
> On Nov 11, 11:27 pm, c...@pobox.com (Chap Harrison) wrote:
> Not lots shorter but you could use a closure to hide
> the calculation:
>
> my $mask;
> for my $flags ( ... ) {
> $mask = sub { return ($flags & $_[0]) == $_[0] }
> unless $mask;
> given( $flags ) {
> when ( $mask->($one_and_three) ) { ... }
> when ( $mask->($zero_and_four) ) { ... }
> ...
> }
> }
>
This won't work properly because the closure traps the initial value of
"$flags". For example:
[code]
#!/usr/bin/perl
use strict;
use warnings;
my $closure;
foreach my $name (qw(Sophie Jack Charles Dan Rachel))
{
$closure = sub { print "Hello $name!\n" ; } unless $closure;
$closure->();
}
[/code]
This prints "Hello Sophie!" five times. Either redeclare the closure on every
iteration, or declare it once while using a more outer lexical variable.
Regards,
Shlomi Fish
> --
> Charles DeRykus
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