Re: This could have DWIM better

Don't forget about $_ in your function.

BEGIN {
  *CORE::GLOBAL::length = sub(;$) {
    my $arg = @_ ? $_[0] : $_;
    defined($arg) ? CORE::length($arg) : undef;
  };
}
[download]

Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

Comment on Re: This could have DWIM better Download Code

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Re^2: This could have DWIM better by ysth (Canon) on Mar 02, 2006 at 09:32 UTC
Yikes, that~~'s a bug~~(update: shows a bug in perl itself). The call to length should explicitly be passing $_, but it~~'s not~~ (update: passes nothing) when it is overridden. This causes a problem with lexical $_: `$ perl5.9.4 -w BEGIN{ *CORE::GLOBAL::length = sub (;$) { my $arg = @_ ? $_[0] : $_; defined($arg) ? CORE::length($arg) : undef; } } $_ = "abc"; my $_; $_ = "defghi"; print length; __END__ 3` [download] This should print 6 whether length is overridden or not, but as is prints 3 when it is overridden. Update: after consideration, I think this is just a natural consequence of the ;$ prototype, and should be no longer a problem with a _ prototype (when someone implements that).	[reply] [d/l]
Re^3: This could have DWIM better by japhy (Canon) on Mar 02, 2006 at 14:52 UTC
Sounds like it's passing the package/global $_ instead of the lexical $_. I must've missed the memo on "lexical $_". Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply]
Re^4: This could have DWIM better by ysth (Canon) on Mar 02, 2006 at 18:51 UTC
It's passing nothing. The bug is that the code calling length should always provide the argument. The memo.	[reply]
Re^2: This could have DWIM better by Aristotle (Chancellor) on Mar 01, 2006 at 18:25 UTC
D’oh. Thanks. Makeshifts last the longest.	[reply]


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