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Postings from August 2012
On Fri, Aug 24, 2012 at 09:02:40AM +1000, Damian Conway wrote:
> Michael Peters responded:
>
> > What good explanation would exist for why my code would now (not just fail
> > to match) but fatally die?
>
> Because the original $foo ~~ $x was (potentially) ambiguous.
> Perl doesn't (yet?) properly distinguish between numbers and strings internally,
> so smartmatch can't always tell what kind of data you're giving it.
>
>
> > How would you teach that?
>
> The theory was that the exception itself would teach it:
>
> Ambiguous operand ($x) in smartmatch at example.pl line 7
> (Did you mean "$x" or 0+$x?)
You know, for me the current proposals that lead up to this exception
doesn't make me very happy. If I got to use ~~ plus additional syntax
to force perl to use either == or eq comparison, I might as well use
== and eq to begin with, and save typing.
On top of that, for years we have been buggering people on use of "$var"
as being bad practise, and now we want a warning to promote it?
Besides, if someone were to use:
$var ~~ $x;
and $x could be a number or a regexp, but in one of the runs gets served
the above warning (because this time, the code path has printed out $x),
and changes it to:
$var ~~ 0 + $x;
it ain't going to work well in case $x is a regexp (or a coderef, or has
overloaded ~~ but not +, or has overloaded +, or several other cases), is it?
Abigail
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