Speedup display of regex match

Only subst in the couple hundred chars around the current match position. If the target is hundreds or thousands of lines long then this is always going to be a lot faster. Right now the impact is colossal for target strings of more than a dozen typical text file lines.
jnthn · Apr 30, 2014 · 6d6fb6b · 6d6fb6b
1 parent 30c8475
commit 6d6fb6b
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/lib/Debugger/UI/CommandLine.pm b/lib/Debugger/UI/CommandLine.pm
@@ -131,8 +131,10 @@ my class SourceFile {
             if $cur ~~ Cursor {
                 my $pos = $cur.pos;
                 my $str = $cur.target;
-                my $before = $str.substr(0, $pos).subst(/\n/, '\n', :g).subst(/\t/, '\t', :g);
-                my $after  = $str.substr($pos).subst(/\n/, '\n', :g).subst(/\t/, '\t', :g);
+                my $bfrom  = [max] 0, $pos - 77;
+                my $blen   = [min] 77, $pos;
+                my $before = $str.substr($bfrom, $blen).subst(/\n/, '\n', :g).subst(/\t/, '\t', :g);
+                my $after  = $str.substr($pos,     144).subst(/\n/, '\n', :g).subst(/\t/, '\t', :g);
                 if $before.chars + $after.chars > 77 {
                     if $after.chars > 43 {
                         $after = $after.substr(0, 40) ~ '...';