+++: non-alpha first

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

diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index c7992211b4a3609e3cb1f97567a5ae63f4fc9191..23ab261e92dd3198bfa41e6a17baef3e6e6d6bfc 100644 (file)
--- a/lib/List/Index.pm
+++ b/lib/List/Index.pm
@@ -4,7 +4,10 @@ use 5.010;
 use strict;
 use warnings;
 
-our $VERSION = '1.00';
+use Exporter 'import';
+
+our $VERSION = '1.01';
+our @EXPORT_OK = qw(rangematch);
 
 sub new {
        my ($class, $values) = @_;
@@ -40,7 +43,7 @@ sub ranges {
 
        for my $i (0 .. $#links - 1) {
                my ($link, $lastchar) = $links[$i + 1]->[0] =~ /(.*)(.)/;
-               $link .= $lastchar eq '.' ? 'z' : chr( ord($lastchar) - 1 )
+               $link .= $lastchar eq '.' ? 'a' : chr( ord($lastchar) - 1 )
                        unless $lastchar eq 'a';
                $links[$i]->[1] = $link;
        }
@@ -49,6 +52,63 @@ sub ranges {
        return \@links;
 }
 
+sub rangematch {
+       my ($link) = @_;
+       my ($s1, $s2) = $link =~ /([^-]*) - ([^-]*)/x
+               or return qr/^\Q$link/i;
+       my @allow;
+
+       if (length $s1) {
+               my $prefix = '';
+               my $char;
+               for my $i (0 .. length($s1) - 1) {
+                       $char = substr $s1, $i, 1;
+                       my $next = $char;
+                       $next = chr( ord($char) + 1 ) if length $s1 > $i + 1;
+                       my $last = 'z';
+                       if (length $s2 > $i) {
+                               if ($s2 =~ /^\Q$prefix/) {
+                                       $last = substr $s2, $i, 1;
+                                       next if $char eq $last;
+                                       $last = chr( ord($last) - (length $s2 > 1) );
+                                       next if $next gt $last;
+                               }
+                       }
+                       push @allow, $prefix."[$next-$last]";
+               }
+               continue {
+                       $prefix .= $char;
+               }
+       }
+
+       if (length $s2) {
+               my $prefix = '';
+               my $char;
+               for my $i (0 .. length($s2) - 1) {
+                       $char = substr $s2, $i, 1;
+                       my $last = 'z';
+                       if (length $s1 > $i) {
+                               my $c1 = substr $s1, $i, 1;
+                               if ($s1 =~ /^\Q$prefix/) {
+                                       next if $c1 le $char;
+                               }
+                       }
+                       push @allow, $prefix."(?![$char-$last])"
+                               if $i or $s1 eq '';
+               }
+               continue {
+                       $prefix .= $char;
+               }
+
+               push @allow, $prefix
+                       if $s2 =~ /^\Q$prefix/ and $s1 le $s2
+                       and not (length $s2 == 1 && length $s1 >= length $s2 && $s1 ne $s2);
+       }
+
+       my $match = sprintf @allow <= 1 ? '%s' : '(?:%s)', join('|', @allow);
+       return qr/^$match/i;
+}
+
 1;
 
 __END__
@@ -62,7 +122,11 @@ List::Index - Paginate alphabetic entries by finding minimal prefixes
        use List::Index;
        my $index = List::Index->new(\@values);
        my @pages = $index->ranges({pagesize => 50});
-       printf '<a href="?start=%s&amp;end=%s">%1$s</a> ', @$_ for @pages;
+       printf '<a href="?q=%s-%s">%1$s</a> ', @$_ for @pages;
+
+       use List::Index 'rangematch';
+       my $limit = rangematch('b-bmq');  # matches prefix like 'baa'..'bmq'
+       @results = grep { $limit } @results;
 
 =head1 DESCRIPTION