http://www.perlmonks.org?node_id=1039191


in reply to Re^2: Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub
in thread Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub

From my slightly cargo-culty perspective on what's going on here, I think that bug looks like it - especially given that non-bitwise ops don't seem to show the weirdness, and since nor does putting the constant string in a variable before doing the &:

use Devel::Peek; use strict; no warnings "numeric"; sub xx { my $arg = shift; my $const = ""; print "(" . ($arg & $const) . ")\n"; } xx("ff"); xx(7); xx("ff");
This code gives:
SV = PV(0x100802558) at 0x1008474e0 REFCNT = 1 FLAGS = (PADMY,POK,pPOK) PV = 0x1002074f0 "ff"\0 CUR = 2 LEN = 8 () SV = PVIV(0x100803c58) at 0x1008474e0 REFCNT = 1 FLAGS = (PADMY,IOK,pIOK) IV = 7 PV = 0x1002074f0 "ff"\0 CUR = 2 LEN = 8 (0) SV = PVIV(0x100803c58) at 0x1008474e0 REFCNT = 1 FLAGS = (PADMY,POK,pPOK) IV = 7 PV = 0x1002074f0 "ff"\0 CUR = 2 LEN = 8 ()