Dan Anderson wrote:
> I have a module that works with a couple of different file handles. Is
> it possible to hide them within an anonymous hash? {} (i.e. the objects
> data). Right now I have:
>
> if (condition_is_met()) {
> open("FILE","<file");
> }
>
> This is in the main body of my package (and thus, I assume, accessible
> by all functions). Is it better to use tighter encapsulation (i.e. a
> closure or throwing it into an anonymous hash) or just to leave it in
> the body?
I think you'd be safe like this, except that if you have a lot of them
then you dont' know what the filehandle is going to be called. Here
you've used *Package::FILE, but there's no general way of getting to
that package name from any given filename. How about a hash of glob
references?
Here's a closure with a subroutine which keeps a list of handles for
each file it has already opened. The program just uses it to print
the next line from alternate files.
I hope this helps.
Rob
use strict;
use warnings;
line_from ('filea');
line_from ('fileb');
line_from ('filea');
line_from ('fileb');
line_from ('filea');
line_from ('fileb');
{
my %filehandle;
my $fh;
sub line_from {
my $file = shift;
$fh = $filehandle{$file};
unless (defined $fh) {
open $fh, $file or die $!;
$filehandle{$file} = $fh;
}
print scalar <$fh>;
}
}
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