Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!convex!usenet
From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: comp.lang.perl
Subject: Re: sort usersub.
Message-ID: <1991Apr09.033830.737@convex.com>
Date: 9 Apr 91 03:38:30 GMT
References: <SAKOH.91Apr9072113@sraco2.us.sra.co.jp>
Sender: usenet@convex.com (news access account)
Reply-To: tchrist@convex.COM (Tom Christiansen)
Organization: CONVEX Software Development, Richardson, TX
Lines: 25
Nntp-Posting-Host: pixel.convex.com

From the keyboard of sakoh@sraco2.us.sra.co.jp (Hiroshi &):
:What's wrong with this program?
:
:	#!/usr/bin/perl
:	sub as_numeric { $a <=> $b; }
:
:	package other;
:
:	@c = (2,3,2,6,4,2);
:	@d = sort main'as_numeric @c;
:
:	for $e (@d) {
:		print "$e\n";
:	}

What's wrong is that $a and $b are compiled in the main routine, but
are being passed in as $other'a and $other'b.  Solutions are:

1) move the subroutine declaration below the package statement.
2) reference the vars with their $other' qualification.
3) pull out the package with caller and use an eval to get it right.

perl -w points out the problem, albeit non-obviously.

--tom