fix rangematch('zz-')

[perl/list-index.git] / lib / List / Index.pm

diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index 7214ced50c43057d929f8f34b9bf943016e134e3..3663c2459422638225058204dbc9854f667f315f 100644 (file)
--- a/lib/List/Index.pm
+++ b/lib/List/Index.pm
@@ -23,31 +23,53 @@ sub ranges {
        my $pages    = $options->{pages   } || 1 + int $#$self / $pagesize;
 
        $pagesize = @$self / $pages;
-       my $offset = 0;
-       my @links;
+       my $offset = $pagesize;
+       my @links = ('');
        while ($offset < @$self) {
                my $link = substr $self->[$offset], 0, $length;
                if ($context) {
-                       my $trim = 1;
-                       my $before = $offset > $context ? $self->[$offset - $context] : '';
-                       for my $match (split //, $before) {
-                               scalar $link =~ /\G\Q$match/g or last;
-                               $trim++;
+                       {
+                               # take a value slightly before the current offset
+                               my $before = $offset > $context ? $self->[$offset - $context] : '.';
+                               # see how much of it matches the current link
+                               my $trim = 1;
+                               for my $match (split //, $before) {
+                                       scalar $link =~ /\G\Q$match/g or last;
+                                       $trim++;
+                               }
+                               # truncate link upto where the earlier value starts to differ
+                               substr($link, $trim) = '' unless $trim > length $link;
+                       }
+
+                       if ($offset + $context < $#$self) {
+                               # take a value after the current offset
+                               my $after = $self->[$offset + $context];
+                               # see how much of it matches the current link
+                               my $trim = 1;
+                               for my $match (split //, $after) {
+                                       scalar $link =~ /\G\Q$match/g or last;
+                                       $trim++;
+                               }
+                               # use this link if it's shorter
+                               if ($trim < length $link) {
+                                       $link = substr $after, 0, $trim;
+                               }
                        }
-                       substr($link, $trim) = '' unless $trim > length $link;
                }
 
-               push @links, [$link];
+               push @links, $link;
                $offset += $pagesize;
        }
 
+       use List::MoreUtils 'uniq';
+       @links = uniq @links;
        for my $i (0 .. $#links - 1) {
-               my ($link, $lastchar) = $links[$i + 1]->[0] =~ /(.*)(.)/;
-               $link .= $lastchar eq '.' ? 'z' : chr( ord($lastchar) - 1 )
-                       unless $lastchar eq 'a';
-               $links[$i]->[1] = $link;
+               my ($link, $lastchar) = $links[$i + 1] =~ /(.*)(.)/;
+               $link .= $lastchar le 'a' ? '.' : chr( ord($lastchar) - 1 );
+               next if $link eq $links[$i] and $i;
+               $links[$i] .= '-'.$link;
        }
-       $links[-1]->[1] = '';
+       $links[-1] .= '-';
 
        return \@links;
 }
@@ -59,6 +81,10 @@ sub rangematch {
        my @allow;
 
        if (length $s1) {
+               if (length $s2) {
+                       $s1 le $s2 or $s1 =~ /^\Q$s2/ or return undef;
+               }
+
                my $prefix = '';
                my $char;
                for my $i (0 .. length($s1) - 1) {
@@ -66,6 +92,7 @@ sub rangematch {
                        my $next = $char;
                        $next = chr( ord($char) + 1 ) if length $s1 > $i + 1;
                        my $last = 'z';
+                       next if $next gt $last;
                        if (length $s2 > $i) {
                                if ($s2 =~ /^\Q$prefix/) {
                                        $last = substr $s2, $i, 1;