Re: foreach funny business

Consider

#1
sub mychop(\$) {  chop ${shift()} }
[download]

versus

# 2
sub mychop(\$) {  chop ${$_[0]} }
[download]

As perl v5.8.8, the program dies with mychop version #2, but not with version #1.

${shift()} copies (via shift()) $_[0] into a ref-thingy, which is then dereferenced with $ - a behaviour which I deem correct. I would take a die() with #1 as a bug. At version #2 the die() is ok - the reference $_[0] is wrapped into a reference and dereferenced - still $_[0], thus read-only.

mhm.. really? oh, wait...

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

Comment on Re: foreach funny business Select or Download Code

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Re^2: foreach funny business by krunchky (Sexton) on Jun 29, 2006 at 20:13 UTC
Running your #2 on my perl does not die, and mine claims to be 5.8.8. Are you sure you're on your rocker? :-) Anyway, to my way of thinking the shift() shouldn't be giving you anything other than _exactly_ what was in $_[0], not some copy. Now who's with me? /me hoists pitchfork and torch	[reply]
Re^3: foreach funny business by shmem (Chancellor) on Jun 29, 2006 at 20:34 UTC
I'm with you, you're right, I'm not. And then, again you're right - 5.8.8 doesn't die, I copied from the wrong shell, and shift() should just pass $_[0], not a copy, unless somebody made `shift` ro-aware. Have to look after this... Mhm. Scanning perldelta... nothing. Then, it's a bug. Or it's just undefined behaviour? But hey, it's a clever one. It's like, say, putting your hand in the band-saw, and get a finger cut, but then you draw out your hand and it's ok because it's read-only. One finger extra ;-) --shmem _($_=" "x(1<<5)."?\n".q·/)Oo. G°\ / /\_¯/(q / ---------------------------- \__(m.====·.(_("always off the crowd"))."· ");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}	[reply] [d/l]