http://www.perlmonks.org?node_id=480102

Tanalis has asked for the wisdom of the Perl Monks concerning the following question:

I'm currently working on a script to performs auto-categorisation of data elements based on rules generated from their characteristics.

These categorisation rules change periodically, and hence I've created a rules file to perform the categorisation and return a suitable category and reason to the calling sub.

My problem: I'm struggling to have eval return anything. According to the docs:

In both forms, the value returned is the value of the last expression evaluated inside the mini-program; a return statement may be also used, just as with subroutines.

.. but that doesn't seem to work for me.

A typical rule might look like the following, where $abs_diff and $source are defined within the sub performing the eval:

return( "A", "Cat A" ) if $abs_diff < 75_000 and $source eq "ICE";

I've tried the following:

# process analysis rules foreach( @$analysis_rules ) { eval $_; }
and
# process analysis rules foreach( @$analysis_rules ) { my( $cat, $comment ) = eval $_; return( $cat, $comment ) if $cat and $comment; }
among a bunch of variations without luck.

Can anyone see where I'm going wrong?

Thanks in advance ...

Update: Fixed a typo in the rule - thanks to holli for pointing that out :)