[Haskell-cafe] is 256M RAM insufficient for a 20 millionelement Int/Int map?

Max Bolingbroke batterseapower at hotmail.com
Sun Oct 19 20:40:11 EDT 2008


2008/10/20 Luke Palmer <lrpalmer at gmail.com>:
> On Sun, Oct 19, 2008 at 5:05 PM, Don Stewart <dons at galois.com> wrote:
>> In general, being able to specialise polymorphic structures so they look like unpacked
>> monomorphic ones would be awesome.
>>
>>    (!Int, !Bool)     ->   (,) {-# UNPACK #-}!Int {-# UNPACK #-}!Bool
>
> I repeat my concern about this notation and the implications thereof.
> (!Int, !Bool) cannot be passed to a function accepting (a,b).
>
> However, I feel there's something very useful here that should be
> fleshed out rather than hacked.  For example, a theory of composable
> strict structures in a lazy language.

This paper might be of interest to you, assuming you haven't seen it:
http://research.microsoft.com/~simonpj/papers/not-not-ml/index.htm. It
doesn't really deal with the issue of UNPACKed data structures, but
does show the first steps towards making sense of types like [!Int] vs
[Int] (if we consider !Int as an "ML-style Int" (albeit a boxed one)
and Int as the vanilla Haskell flavour).

Cheers,
Max


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