Some thoughts on foreach reverse

p4raw-id: //depot/perl@23104

diff --git a/pod/perltodo.pod b/pod/perltodo.pod
index db7274c..1560956 100644 (file)
--- a/pod/perltodo.pod
+++ b/pod/perltodo.pod
@@ -183,6 +183,10 @@ code review. Also fchdir is available in some platforms."
 
 The old perltodo notes that we could optimise foreach to iterate in reverse.
 (instead of making a reversed copy on the stack)
+It seems that cx->blk_loop.itermax could be hijacked to act as a go up/go
+down flag, with cx->blk_loop.iterix primed in pp_enteriter for the go down
+case (ie reverse). However, it looks slightly tricky identifying the shape of
+foreach reverse in the optree in Perl_peep.
 
 =head1 Tests