more legible code to add range ends

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

diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index e67e5ae730202bafb8bd4ff3640d35656b51c129..719aca74ed00acf60feddb2437bcce314410277f 100644 (file)
--- a/lib/List/Index.pm
+++ b/lib/List/Index.pm
@@ -23,11 +23,11 @@ sub ranges {
        my $pages    = $options->{pages   } || 1 + int $#$self / $pagesize;
 
        $pagesize = $pages >= $#$self ? 1 : @$self / $pages;
-       my $offset = $pagesize + .5;
        my $lookbehind = -$context;
        my $lookahead  =  $context;
+
        my @links = ('');
-       while ($offset < @$self) {
+       for (my $offset = $pagesize + .5; $offset < @$self; $offset += $pagesize) {
                my $link = substr $self->[$offset], 0, $length;
                if ($context) {
                        my $penalty = 0;
@@ -74,18 +74,18 @@ sub ranges {
                        $lookahead = $context - $penalty;
                }
 
-               push @links, $link;
-               $offset += $pagesize;
+               push @links, $link unless $links[-1] eq $link;
        }
 
-       use List::MoreUtils 'uniq';
-       @links = uniq @links;
+       # add range end to each link
        for my $i (0 .. $#links - 1) {
-               my ($link, $lastchar) = $links[$i + 1] =~ /(.*)(.)/;
-               $link .= $lastchar le 'a' ? '.' : chr( ord($lastchar) - 1 );
-               next if $link eq $links[$i] and $i;
-               $links[$i] .= '-'.$link;
+               # end at start of next value with the last character decremented
+               my $next = $links[$i + 1];
+               $next =~ s{(.)$}{ $1 le 'a' ? '.' : chr( ord($1) - 1 ) }e;
+               # amend range if it's ahead
+               $links[$i] .= '-'.$next unless $next eq $links[$i];
        }
+       # final value takes the rest
        $links[-1] .= '-';
 
        return \@links;