>>>>> "LP" == Luke Palmer <[EMAIL PROTECTED]> writes:
>> # P5: @sorted = sort { $a->foo('bar')->compute <=> $b->foo('bar')->compute }
>> # @unsorted
>> # or: @sorted = map { $_->[1] }
>> # sort { $a->[0] <=? $b->[0] }
>> # map { [ $_->foo('bar')->compute, $_ ] }
>> # @unsorted
>> @sorted = sort &infix:<=>, key => { $_.foo('bar').compute } <== @unsorted;
LP> Ok, I have to say, that's pretty good. Er, really good. I like it a
LP> lot.
how do you select descending order? and how do you selecte that per key?
you can't provide a binary operator without also providing the
order. and what about different key types? the <=> and cmp operators are
not enough information needed to do complex sorts. collating sequences
are another issue. you need to have that info on a perl key basis.
>> I think my suggestion wins big here. We've only had to specify how
>> to extract the key, and sort itself takes care of everything else.
>> And it looks to me like this sort function has enough information
>> about the programmer's intent for it to optimise in all sorts of
>> exciting ways -- it should be able to do the equivalent of the GRT
>> internally, for example.
sort can't figure it out without you telling it things. you need more
than just key extraction.
>> Just for kicks, this one demonstrates all the features. It's the same as
>> before, but in descending order:
>>
>> @unsorted
>> ==> sort &infix:<=>, desc => 1, key => { $_.foo('bar').compute }
>> ==> @sorted;
>>
>> What problems can anyone spot with this suggestion?
multiple keys with each having different comparisons and different sort
orders.
LP> @unsorted
LP> ==> sort { $^b <=> $^a }, key => { .foo('bar').compute }
LP> ==> @sorted
LP> Which people have made pretty clear that they don't like.
as i have said before. needing to have $a and $b in the correct order is
bug prone and confusing to many.
uri
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