Array lookups and extra arithmetic in Perl is slower than
bumping the internal array offset inside the interpreter.
Fwiw, using: my ($level, $subj) = splice(@extra, 0, 2)
did not result in a performance improvement.
---
lib/PublicInbox/View.pm | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 5fbdd1fa..9846fa47 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -1188,9 +1188,9 @@ sub dump_topics {
my $s = "<a\nhref=\"$href/T/$anchor\">$top_subj</a>\n" .
" $ds UTC $n\n";
- for (my $i = 0; $i < scalar(@extra); $i += 2) {
- my $level = $extra[$i];
- my $subj = $extra[$i + 1]; # already normalized
+ while (@extra) {
+ my $level = shift @extra;
+ my $subj = shift @extra; # already normalized
$mid = delete $seen->{$subj};
my @subj = split(/ /, $subj);
my @next_prev = @subj; # full copy
