Comment empty match early termination reasoning

Author: hoelzro

ack

@@ -537,7 +537,11 @@ sub print_matches_in_resource {
             while ( $contents =~ /$opt_regex/og ) {
                 my $match_start = $-[0];
                 my $match_end   = $+[0];
-                next if $match_start == $match_end;
+                next if $match_start == $match_end; # continue to the next line
+                                                    # if we match nothing, since
+                                                    # some regexes allow this
+                                                    # and would throw us into
+                                                    # an infinite loop
 
                 pos($contents)  = $prev_match_end;
                 $prev_match_end = $match_end;
@@ -641,7 +645,9 @@ sub print_line_with_options {
                     my $offset = 0; # additional offset for when we add stuff
                     my $previous_match_end = 0;
 
-                    last if $-[0] == $+[0];
+                    last if $-[0] == $+[0]; # stop highlighting if we've hit an
+                                            # empty match, since continuing would
+                                            # result in an infinite loop
 
                     for ( my $i = 1; $i < @+; $i++ ) {
                         my ( $match_start, $match_end ) = ( $-[$i], $+[$i] );
@@ -672,7 +678,9 @@ sub print_line_with_options {
                     $matched = 1;
                     my ( $match_start, $match_end ) = ($-[0], $+[0]);
                     next unless defined($match_start);
-                    last if $match_start == $match_end;
+                    last if $match_start == $match_end; # stop highlighting if we've hit an
+                                                        # empty match, since continuing would
+                                                        # result in an infinite loop
 
                     my $substring = substr( $line, $match_start,
                         $match_end - $match_start );