Sort::Maker : anonymous sub is compiled outside of my module

I wanted to see how Sort::Maker could be used to sort the "meascodes" in this message:

http://groups.google.com/groups?selm=1165272390.675288.234670@xxxxxxxxxxxxxxxxxxxxxxxxxxx

To do this, I wrote this program:

132 use strict;
133 use warnings;
134 use Data::Dumper;
135 use Sort::Maker;
136
137 my $cost_order = 'A2yB';
138 my @sorted;
139
140 my $ms = [
141 '<table><tr><td meascode=\'y\'> </td></tr></table>',
142 '<table><tr><td meascode=\'B\'> </td></tr></table>',
143 '<table><tr><td meascode=\'2\'> </td></tr></table>',
144 '<table><tr><td meascode=\'A\'> </td></tr></table>'
145 ];
146
147 my $sorter = make_sorter(
148 plain => string => sub {
149 if (/meascode='(.)'/) {index($cost_order,$1)}
150 },
151 );
152 if ($@) { print "$@\n"; exit; }
153 @sorted = $sorter->(@$ms);
154 print Dumper(\@sorted);

However, this fails with "Global symbol "$cost_order" requires explicit package name at (eval 12) line 8."

I was a little surprised, since anonymous subs usually have access to lexical variables. I decided to make $cost_order a package variable (in main) and fully qualify it as $::cost_order in the anonymous sub, so I changed the lines of the program like so:

137 our $cost_order = 'A2yB';
149 if (/meascode='(.)'/) {index($::cost_order,$1)}

However, it fails again with the same error message as before. Thankfully, it prints out the key extraction code which shows that my colons have been removed from $::cost_order, and even when I use $main::cost_order, it gets changed to $cost_order--which causes the failure.

I then decided to change the variable $cost_order to a subroutine:

137 sub COST_ORDER { 'A2yB' }
149 if (/meascode='(.)'/) {index(COST_ORDER(),$1)}

And I get this error message: "Undefined subroutine &Sort::Maker::COST_ORDER called at (eval 12) line 8."

It looks like my anonymous sub is being compiled in Sort::Maker. No problem, I'll just put the qualifiers on the COST_ORDER():

149 if (/meascode='(.)'/) {index(::COST_ORDER(),$1)}

But it fails with the same error message. I can only assume that the colons were stripped from COST_ORDER() before the anonymous sub was compiled. Finally, I had an insight: Sort::Maker likes stuff to be in its package, so I try this:

137 sub COST_ORDER { 'A2yB' }
146 *{Sort::Maker::COST_ORDER} = \&COST_ORDER;
149 if (/meascode='(.)'/) {index(COST_ORDER(),$1)}

And it works.

Evidently, there is a bug/undocumented feature that causes an anonymous sub that the programmer writes in his package to be compiled in Sort::Maker, and Sort::Maker seems to make some modifications to the *text* of that subroutine before it's compiled :O

Perl 5.8.4
Sort::Maker 0.05
Debian 3.1 (i686)


--
paduille.4060.mumia.w@xxxxxxxxxxxxx
.

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