[Haskell-cafe] Re: Looking for the fastest Haskell primes

[Eugene Kirpichov]

The parameterless version is a top-level definition and won't get
garbage-collected, IIRC.
So, if you evaluate primes!!10000000, you'll end up with a
10000000-element list hanging in memory forever.
If you evaluate (primes' ()) !! 10000000, you won't.

2009/4/16 Niemeijer, R.A. <r.a.niemeijer at tue.nl>:
> Heinrich Apfelmus wrote:
>> +1 except that exporting the potentially infinite list of primes is
>> problematic in that it may become a memory leak.
>>
>> I'd suggest to export two versions
>>
>>   primes  :: [Integer]
>>   primes' :: () -> [Integer]
>>
>> for casual (i.e. throwaway program to solve a Project Euler problem) and
>> for memory aware use respectively.
>
> I'm afraid I don't quite follow. Would you mind explaining what the first parameter is for and how it would solve the memory leak?
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-- 
Eugene Kirpichov
Web IR developer, market.yandex.ru