Mistaken notions of $a/$b strict

My answer was tongue firmly in cheek. Note the tone and the :)'s scattered about. But please, submit a patch.

To clear up a misconception though, your "action at a distance" horror scenario there won't happen. No sir. $a and $b are (apparently) local'd to the block:

@list=qw( one two three four five );

$a="Hello";
$b="World";
sort { $a <=> $b } @list;
print "$a $b";  # Hello World
[download]

I knew this. Several others in channel this morning knew this. But in an ironic twist of events, I can't find where that localization is documented. I think I see it in the Perl source...but not in the docs.

Comment on Mistaken notions of $a/$b strict Download Code

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Re: Mistaken notions of $a/$b strict by dragonchild (Archbishop) on Feb 28, 2002 at 16:02 UTC
Ah, but the "action at a distance" most certainly does occur. If you create a sorting sub in one module and use it in another ... Look at the following code: `my $a = 5; my @b = reverse (0 .. 9); print "@b\n"; sub boo { $a <=> $b } @b = sort boo @b; print "@b\n"; print $a,$/; ---- 9 8 7 6 5 4 3 2 1 0 0 1 2 3 4 9 8 5 6 7 5` [download] Note the lack of sorting after 4. :-) ------ We are the carpenters and bricklayers of the Information Age. Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.	[reply] [d/l]
Re2: Mistaken notions of $a/$b strict by blakem (Monsignor) on Mar 01, 2002 at 02:13 UTC
While I don't have time to fully explain it, you can actually use prototypes(bleck) to avoid the weirdness in $a and $b (ughhh) for 5.6 and above.... `sub boo ($$) { my ($a,$b) = @_; $a <=> $b }` [download] -Blake	[reply] [d/l]
Re: Re2: Mistaken notions of $a/$b strict by dragonchild (Archbishop) on Mar 01, 2002 at 14:28 UTC
Actually, just scoping $a and $b to boo() is enough. I didn't realize they were passed in through @_. :-) ------ We are the carpenters and bricklayers of the Information Age. Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.	[reply]


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