In article <[EMAIL PROTECTED]>, John W. Krahn wrote: [...] > Perhaps this article may help you understand. > > http://perl.plover.com/FAQs/Namespaces.html
I've read this before (but it pays to reread it) and this time I also read the "Seven Useful Uses of local". One thing MJD demonstrates is a clever wayt that one can write one's one "map" and "grep"-like methods/functions. Only problem is that I can't get it to work. I get the error: Use of uninitialized value in concatenation (.) or string at ./sub_print_hash line 20. Can't call method "printhash" without a package or object reference at ./sub_print_hash line 20. Here is my code: #!/usr/bin/perl use warnings; use strict; # sub_print_hash # from MJD's "Seven Useful Uses of local" - http://perl.plover.com/local.html # very useful technique for building your own grep and map-like functions! my %capitals = ( Athens => "Greece", Moscow => "Russia", Helsinki => "Finland", ); foreach (keys %capitals) { print "$_ => $capitals{$_}\n"; } printhash { "$a," } %capitals; #printhash { "$a => $b\n" } %capitals; sub printhash (&\%) { my $code = shift; my $hash = shift; local ($a, $b); while (($a, $b) = each %$hash) { print &$code(); } } -- Kevin Pfeiffer -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
