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Postings from February 2013
On Wednesday February 20 2013 9:45:19 AM Ed Avis wrote:
> Jesse Luehrs <doy <at> tozt.net> writes:
> >$_ is basically useless except for the global form.
> >
> >"my $_ = 'foo'; my @bar = any { $_ eq 'a' } qw(a b c)"
>
> Might it be better for higher-order functions like map, any, and sort to
> pass the argument as an argument, rather than in $_? Unfortunately there
> is a lot of existing code that relies on global $_ as you point out.
Please, no. One of the nice features here, IMO, is that a "topic" is set and
we can just use it. (I'd _almost_ argue for 'eq' and kin to accept the topic,
making the above "my @bar = any { eq 'a' } qw(a b c)", but that's too far.)
my $has_vowel = any { /[aeiou]/ } @list;
Sometimes, it makes sense to pass in a parameter. But for small uses like
this, a localised $_ is awesome.
Now, I grant, sometimes I have a map inside a map, or an any inside a map, and
the repeated $_'s gets annoying, but I've found that to be rare. I'd rather
be forced to write "my $topic = $_;" at the top of the outer map in the rare
case than to lose $_ for the common case.
As to the original topic, I'd love to see lexical $_ stay. It's a good idea
in the abstract. Unfortunately, when brought into the concrete of reality, I
personally don't see how it can stay when mixed with closures like this. But
please let's not through out the $_ baby with the bathwater here :)
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