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Postings from April 2009
Alberto Simões wrote:
> Mark Mielke wrote:
>> Hakim Cassimally wrote:
>>> I wanted to be able to write:
>>>
>>> my $x = given ($blah) {
>>> ....
>>> default { 'foo' }
>>> }
>>>
>>> ...
>>> Is there a way to work around this limitation?
>>> And would it be worthwhile me submitting a docpatch to perlsyn?
>>>
>> Seems like along that path would lie:
>>
>> my $x = if ($blah) { ... } else { 'foo' };
>>
>
> For the if construct you can always wrap it into an eval:
>
> my $x = eval { if ($blah) { ... } else { 'foo' }; }
Or a do block. Oh god, that works! I suspect its a side effect of Perl
compiling if/else into some sort of || conditionals. while() and foreach()
don't do that.
> Not sure if it works for switch (didn't try).
It doesn't. While I did have that slight taste of vomit in my mouth when I
think about it, I also think about why I write this:
my $foo = cond1 ? first :
cond2 ? second :
cond3 ? third :
default ;
instead of this:
my $foo;
if( cond1 ) { $foo = "first" }
elsif( cond2 ) { $foo = "second" }
elsif( cond3 ) { $foo = "third" }
else { $foo = "default" }
not just because its more concise, but because it clearly shows that the
purpose is an assignment and will (should) have no other side effects.
given/when has no analog to the ternary op. Maybe it doesn't need one:
my $foo = given($blah) {
when(cond1) { "first" }
when(cond2) { "second" }
when(cond3) { "third" }
default { "default" }
};
That's pretty cool.
So +1 to making given/when return the last evaluated expression.
--
Robrt: People can't win
Schwern: No, but they can riot after the game.
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