On Fri, Jan 31, 2003 at 05:59:46PM +0100, Leopold Toetsch wrote:
> A lvalue param is not strictly reading, but here has to happen something
> differently - yes:
>
> IMHO some sort of proxy could be passed here, saying: "if you write to
> me, this will be at @a[0]". Or auto-vivify the entry.
This is what Perl 5 does at the moment:
$ perl5.8.0 -MDevel::Peek -e 'sub f{Dump($_[0])}; f($a[9])'
SV = PVLV(0x8177118) at 0x8166a74
REFCNT = 1
FLAGS = (GMG,SMG)
IV = 0
NV = 0
PV = 0
MAGIC = 0x816e7e0
MG_VIRTUAL = &PL_vtbl_defelem
MG_TYPE = PERL_MAGIC_defelem(y)
TYPE = y
TARGOFF = 9
TARGLEN = 1
TARG = 0x817ad88
SV = PVAV(0x8183bd4) at 0x817ad88
REFCNT = 2
FLAGS = ()
IV = 0
NV = 0
ARRAY = 0x0
FILL = -1
MAX = -1
ARYLEN = 0x0
FLAGS = (REAL)
However, I think this is clumsy and overly complex; since Perl6 allows us
to declare parameters rw or whatever, I think it should always autovivify
unless we know the param is read-only (or in-only, or whatever the correct
terminology is).
--
"There's something wrong with our bloody ships today, Chatfield."
Admiral Beatty at the Battle of Jutland, 31st May 1916.
