http://www.perlmonks.org?node_id=810040


in reply to Re^3: Building a UNIX path from Irritating data
in thread Building a UNIX path from Irritating data

Hi kyle --

I've been working on your code for a while, and I cannot yet see how it builds a path, and I cannot get it to work for me. I copied your code above exactly as you said and used the data file that I provided, but here's the output I get:

100 => 100 101 => 101 1013 => 1013 1014 => 1014 1015 => 1015 1053 => 1053 1057 => 1057 1059 => 1059 1065 => 1065 119 => 119 1198 => 1198 1227 => 1227 1228 => 1228 1229 => 1229 1230 => 1230 1231 => 1231 1232 => 1232 1233 => 1233 1234 => 1234 1238 => 1238 1239 => 1239 1241 => 1241 1298 => 1298 1299 => 1299 1300 => 1300 1311 => 1311 1317 => 1317 1318 => 1318 1320 => 1320 1321 => 1321 1322 => 1322 1323 => 1323 1324 => 1324 1325 => 1325 1327 => 1327 1328 => 1328 1329 => 1329 1347 => 1347 1348 => 1348 1349 => 1349 1350 => 1350 1351 => 1351 1352 => 1352 1374 => 1374 1375 => 1375 1376 => 1376 1377 => 1377 1390 => 1390 1393 => 1393 1394 => 1394 1395 => 1395 1396 => 1396 1397 => 1397 1398 => 1398 ...
I think the line that may be wrong in my code is this one:
return @parents ? [ map { map { "$_/$folderid" } @{ build_path( $_ ) } } @parents ] : [ $folderid ];
I've never seen a "return" command used in a conditional this way. It would seem to me that in order for the conditional to be true, the focus would have already returned to the line calling build_path originally. Does this actually mean if "return @parents" would succeed then do X, if not, Y?

I really appreciate your help. I think this is very close to what I need, but I'm missing some keystone. To make sure I got your code correct, here's the exact script I'm running (in cygwin on a windows system, and on an HPUX system):

#!/usr/bin/perl -w use strict; my $foldername_file = shift @ARGV; my $folderfolder_file = shift @ARGV; my %folders = (); my %folderpaths = (); open(FNAMES,"$foldername_file") or die "Can't open $foldername_file: $ +!\n"; foreach my $folderline (<FNAMES>) { chomp $folderline; if ($folderline =~ /^Folder (\d{3,5})\s+\-\s+(.*)\.$/) { $folders{$1} = $2; } } close(FNAMES); open(FFINFO,"$folderfolder_file") or die "Can't open $folderfolder_fil +e: $!\n"; my @subfolders = <FFINFO>; my %parents_of; my $parentid; while ( my $line = <FFINFO> ) { if ($line =~ /^Folder (\d{3,5})\s+\-\s+.*\./) { $parentid = $1; } elsif ($line =~ /\s+subfolder\s+(\S+)\s+\-\s+.*\./) { push @{ $parents_of{ $1 } }, $parentid; } } sub build_path { my $folderid = shift @_; my @parents = @{ $parents_of{ $folderid } || [] }; return @parents ? [ map { map { "$_/$folderid" } @{ build_path( +$_ ) } } @parents ] : [ $folderid ]; } foreach my $k (sort (keys (%folders))) { $folderpaths{$k} = build_path($k); print "$k => $_\n" for @{ $folderpaths{$k} }; }