X-Git-Url: http://git.shiar.net/perl/list-index.git/blobdiff_plain/3df9395c1a2f641564d8fca7fc843d066d1411d4..0433a4eb785409f46a2d61e668fda84bd87c3148:/lib/List/Index.pm

diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index c799221..7214ced 100644
--- 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) = @_;
@@ -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