I am processing different types of files, some compressed and some uncompressed. The uncompressed ones I can open with just

open(HANDLE, $filename) or die ...

and the compressed ones with

open(HANDLE, "$unzip $unzip_opts $filename |") or die ...

These two different ways of opening a file are in two different sub's - _open_unzipped and _open_zipped

I also have a sub called _detect_type that uses some logic to work out which open routine is required. And it returns a reference to the required sub 

sub _detect_type {
  ... # logic to determine type
  return \&_open_unzipped if $rule1;
  return \&_open_zipped   if $rule2;
  return undef;
}

[download]

All of this is wrapped up in a module Import.pm (shocking name I know ...) 

package Import;
use Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(load_file);
@EXPORT_OK = qw(_detect_type
                _open_zipped
                _open_unzipped
               );
%EXPORT_TAGS = {STD  => \@EXPORT,
                TEST => \@EXPORT_OK
               };

sub load_file {
  my $filename = shift;
  my $openner = _detect_type($filename);
  &$openner($filename);
  while (my $line = <HANDLE>) {
    ... # do stuff with lines
  }
}

sub _detect_type   {...}
sub _open_zipped   {...}
sub _open_unzipped {...}
1;

[download]

Furthermore, I am a good little vegemite and I have a test harness for all this in t/Import.t 

use Test::More qw(no_plan);
use Import qw(:TEST);
...
is($test1, $result1);
is($test2, $result2);
...

[download]

Now to my problem - how do I check which code reference I got back from _detect_type.

This doesn't always work - sometimes the code reference matches and sometimes it doesn't. 

is(_detect_type('unzipped.txt'), \&open_unzipped);
is(_detect_type('zipped.zip'),   \&open_zipped);

[download]

Is what I am doing unreasonable - or fraught with issues?

I am using Perl 5.6.0 on RH 6.2 Linux.

In reply to Comparing references to sub's by leriksen

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