The Strange Loop conference

[Sean Kelly]

You might wan to play with GC.reserve. 

Sent from my iPhone

On Sep 22, 2011, at 4:35 PM, Timon Gehr <timon.gehr at gmx.ch> wrote:

> On 09/22/2011 02:29 PM, Christophe wrote:
>> "Nick Sabalausky" , dans le message (digitalmars.D:145002), a écrit :
>>>> For example, in Haskell, map (correctly) has the signature:
>>>> 
>>>> map :: (a ->  b) ->  [a] ->  [b]
>>>> 
>>>> but in D, std.map has the signature (expressed in some Haskell/D
>>>> pseudocode)
>>>> 
>>>> map :: (a ->  b) ->  [a] ->  Map!((a ->  b), [a])
>> 
>> except that [a] should be a D Range, and that Map is a D Range too.
>> So I'd go for:
>> 
>> map :: (a ->  b) ->  Range!A ->  Range!B
>> 
>> oh, that's quite close to Haskell's map...
>> 
>> 
>> Let me try the other game: what is Haskell's signature ?
>> I need to introduce Haskell's type to D, so:
>> 
>> // all types are lazy pure:
>> template Haskell(T)
>> {
>>     alias pure T function() Haskell;
>> }
>> 
>> // Haskell's list:
>> template HaskellR(T)
>> {
>>     alias pure Tuple!(Haskell!A, HaskellR!T) function() HaskellR;
>> }
>> 
>> // Then the signature of map is:
>> HaskellR!B map(A,B)(Haskell!B function(Haskell!A), HaskellR!A);
>> 
>> Experienced Haskell's users may correct me.
>> 
>> All functions must be pure, and those pure function, and a lot of
>> optimization comes from the memoization of those functions.
>> Haskell!T could be rewritten to take into account this memoization.
>> 
>> I wonder what efficiency would we get compared to Haskell with a library
>> based on this kind of stuff in D. We would probably miss many
>> optimization opportunities that Haskell is tuned to find out, but it
>> must be fun to try that out.
>> 
> 
> I did: http://pastebin.com/2rEdx0RD
> 
> port of some haskell code from RosettaCode (run it ~20 min to get results, haskell runs in less than 2s)
> http://pastebin.com/Vx4hXvaT
> 
> Output of the second example is screwed up with the latest release though, I don't know why, but converting BigNums to string is a PITA anyways... Has there been a regression in the std.bigint.BigInt.toString code?
> 
> 
> The main performance issue is the garbage collector. Turning it off will help performance a lot if you have enough RAM. Furthermore, DMD does not do any advanced optimizations
> 
> 
>