From: Nicholas Clark <nick@ccl4.org>
Date: Sun, 6 Apr 2008 19:32:03 +0000 (+0000)
Subject: Add attempting Exterminate! cop_label to perltodo.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=439cad7f0af0ff91bdf31605de1593fa2b4842c3;p=p5sagit%2Fp5-mst-13.2.git

Add attempting Exterminate! cop_label to perltodo.

p4raw-id: //depot/perl@33652
---

diff --git a/pod/perltodo.pod b/pod/perltodo.pod
index 227fd6b..35ee02a 100644
--- a/pod/perltodo.pod
+++ b/pod/perltodo.pod
@@ -720,6 +720,28 @@ also the warning messages (see L<perllexwarn>, C<warnings.pl>).
 These tasks would need C knowledge, and knowledge of how the interpreter works,
 or a willingness to learn.
 
+=head2 Abolish cop_label?
+
+C<struct cop> contains
+
+    char *	cop_label;	/* label for this construct */
+
+Most statements don't have labels. It might be possible to eliminate this
+member and instead store the label, if present, in
+
+    struct refcounted_he * cop_hints_hash;
+
+(with a hint bit, similar to
+
+    #define HINT_ARYBASE	0x00000010 /* $[ is non-zero */
+    #define HINT_LEXICAL_IO_IN	0x00040000 /* ${^OPEN} is set for input */
+    #define HINT_LEXICAL_IO_OUT	0x00080000 /* ${^OPEN} is set for output */
+
+). The trick would be ensuring that this faked lexical hint doesn't get
+propagated to nested scopes. It might be as simple as moving the setting of
+"cop_label" in C<Perl_newSTATEOP> after the code to set up
+C<cop->cop_hints_hash>.
+
 =head2 lexicals used only once
 
 This warns: