# New Ticket Created by Brandon Allbery
# Please include the string: [perl #125542]
# in the subject line of all future correspondence about this issue.
# <URL: https://rt.perl.org/Ticket/Display.html?id=125542 >
Inspired by a p6-users message where someone was confused after attempting
to naïvely translate a use of P5ish refs to P6. Possibly the inverse case
(mistaking %(...) for P5's %{...} and similar) should also warn, and
possibly this should be made to only occur once per compilation unit.
(attached)
--
brandon s allbery kf8nh sine nomine associates
allber...@gmail.com ballb...@sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
>From 0cdc736294742653b2652923f7fcbe3874daab06 Mon Sep 17 00:00:00 2001
From: brandon s allbery kf8nh <allber...@gmail.com>
Date: Fri, 3 Jul 2015 14:35:54 -0400
Subject: [PATCH] Warn on P5ish use of \ on single sigiled variable
---
src/Perl6/Grammar.nqp | 2 ++
1 file changed, 2 insertions(+)
diff --git a/src/Perl6/Grammar.nqp b/src/Perl6/Grammar.nqp
index 42e8eeb..ac2d7aa 100644
--- a/src/Perl6/Grammar.nqp
+++ b/src/Perl6/Grammar.nqp
@@ -2575,6 +2575,8 @@ grammar Perl6::Grammar is HLL::Grammar does STD {
'\\'
[
| '(' <semiarglist> ')'
+ # catch a common perl5-to-perl6 trap involving references
+ | <?before '$' | '@' | '%'> <.worry("To pass an array or hash to a
function in Perl 6, just pass it as is, and for other uses of Perl 5's ref
operator consider binding with ::= instead. Parenthesize as \\(...) if you
intended a capture of a single variable.")> <termish>
| <?before \S> <termish>
| {} <.panic: "You can't backslash that">
]
--
1.9.1
