p5pRT
commented
10 years ago From zefram@fysh.org
Created by zefram@fysh.org
Generally\, a value assigned to an element of a tied hash gets passed through to the tied STORE method\, so any kind of scalar can be handled by a tied hash\, just as an ordinary hash can contain any kind of scalar. But it doesn't work for regexp scalars. Here's what one looks like in an ordinary hash:
$ perl -MDevel::Peek -lwe '$a{x} = ${qr/foo/}; Dump $a{x}' SV = REGEXP(0x14aa9a0) at 0x147ba68 REFCNT = 1 FLAGS = (POK\,FAKE\,pPOK) PV = 0x1490460 "(?^:foo)" CUR = 8 LEN = 0 EXTFLAGS = 0x680000 (CHECK_ALL\,USE_INTUIT_NOML\,USE_INTUIT_ML) INTFLAGS = 0x0 NPARENS = 0 LASTPAREN = 0 LASTCLOSEPAREN = 0 MINLEN = 3 MINLENRET = 3 GOFS = 0 PRE_PREFIX = 4 SEEN_EVALS = 0 SUBLEN = 0 SUBBEG = 0x0 ENGINE = 0x2b04257e50e0 MOTHER_RE = 0x1496c28 PAREN_NAMES = 0x0 SUBSTRS = 0x149a980 PPRIVATE = 0x149ee90 OFFS = 0x1490840
And here's what happens with a tied hash:
$ perl -lwe '{ package Foo; use Devel::Peek; sub TIEHASH { bless({}\, $_[0]) } sub STORE { Dump $_[2] } } my %a; tie %a\, "Foo"; $a{x} = ${qr/foo/}' SV = PVLV(0xe8ae40) at 0xe7d560 REFCNT = 2 FLAGS = (POK\,pPOK) IV = 0 NV = 0 PV = 0xe8e980 "(?^:foo)"\0 CUR = 8 LEN = 16 MAGIC = 0xe8ed20 MG_VIRTUAL = &PL_vtbl_packelem MG_TYPE = PERL_MAGIC_tiedelem(p) MG_FLAGS = 0x02 REFCOUNTED MG_OBJ = 0xe7cd38 SV = IV(0xe7cd28) at 0xe7cd38 REFCNT = 2 FLAGS = (ROK) RV = 0xe61c18 SV = PVHV(0xe66890) at 0xe61c18 REFCNT = 1 FLAGS = (OBJECT\,SHAREKEYS) STASH = 0xe7d5d8 "Foo" ARRAY = 0x0 KEYS = 0 FILL = 0 MAX = 7 RITER = -1 EITER = 0x0 MG_LEN = -2 MG_PTR = 0xe7cea0 => HEf_SVKEY SV = PV(0xe5fd90) at 0xe7cea0 REFCNT = 2 FLAGS = (POK\,pPOK) PV = 0xe87b60 "x"\0 CUR = 1 LEN = 16 TYPE = T TARGOFF = 0 TARGLEN = 0 TARG = 0xe731e8 FLAGS = 0
Note that the value in the scalar received by the STORE method is a plain string\, the stringification of the regexp. The basic problem seems to be a collision between the use of the SvTYPE field to denote a special type of scalar value\, SVt_REGEXP\, and the the use of the same field to denote a special type of scalar container\, SVt_PVLV. Although they're horribly interleaved\, the container and value aspects of scalars are for the most part orthogonal. The failure of orthogonality here is jarring.
Migrated from rt.perl.org#121477 (status was 'open')
Searchable as RT121477$