Send Beginners mailing list submissions to
[email protected]
To subscribe or unsubscribe via the World Wide Web, visit
http://www.haskell.org/mailman/listinfo/beginners
or, via email, send a message with subject or body 'help' to
[email protected]
You can reach the person managing the list at
[email protected]
When replying, please edit your Subject line so it is more specific
than "Re: Contents of Beginners digest..."
Today's Topics:
1. Re: Compiling C into Haskell (Hein Hundal)
2. Re: Compiling C into Haskell (Brent Yorgey)
3. Re: Compiling C into Haskell (Maciej Piechotka)
----------------------------------------------------------------------
Message: 1
Date: Tue, 13 Apr 2010 05:39:04 -0700 (PDT)
From: Hein Hundal <[email protected]>
Subject: Re: [Haskell-beginners] Compiling C into Haskell
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=iso-8859-1
Thanks Allan!
I was hoping the C-Haskell mix would work. I am glad to hear that you have
good things to say about it.
My main reason for thinking about the C-to-Haskell compiler was to address
the question "Say you had a C program. Can you always convert it to Haskell in
such a way that the compiled Haskell is not too slow and does not need too much
memory?" Supposing that too slow means slower than 1/4 the speed of C and too
much memory means twice the memory of C.
Do you know the answer to this question?
Cheers,
Hein
------------------------------
Message: 2
Date: Tue, 13 Apr 2010 10:42:04 -0400
From: Brent Yorgey <[email protected]>
Subject: Re: [Haskell-beginners] Compiling C into Haskell
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=iso-8859-1
On Tue, Apr 13, 2010 at 05:39:04AM -0700, Hein Hundal wrote:
> Thanks Allan!
>
> I was hoping the C-Haskell mix would work. I am glad to hear that you
> have good things to say about it.
>
> My main reason for thinking about the C-to-Haskell compiler was to address
> the question "Say you had a C program. Can you always convert it to Haskell
> in such a way that the compiled Haskell is not too slow and does not need too
> much memory?" Supposing that too slow means slower than 1/4 the speed of C
> and too much memory means twice the memory of C.
>
> Do you know the answer to this question?
My guess is that the answer is technically "no". If I recall
correctly, there are some imperative data structures where the best
known time complexity for a functional version is worse than the
imperative version by a factor of (log n), so in that case you
wouldn't be able to stay within a constant factor of C.
However, I think in practice the answer is usually "yes"; but it might
be hard to do it via a mechanical compilation. Idiomatic (and fast)
Haskell is often organized very differently than corresponding C code.
So if you want to know whether you will necessarily be taking a big
performance hit in moving from C to Haskell, the answer is usually no,
if the translation is sufficiently intelligent --- which a
straightforward C-to-Haskell compiler is (probably) not.
-Brent
------------------------------
Message: 3
Date: Tue, 13 Apr 2010 16:54:37 +0200
From: Maciej Piechotka <[email protected]>
Subject: [Haskell-beginners] Re: Compiling C into Haskell
To: [email protected]
Message-ID: <1271170477.13227.7.ca...@picard>
Content-Type: text/plain; charset="utf-8"
On Tue, 2010-04-13 at 05:39 -0700, Hein Hundal wrote:
> Thanks Allan!
>
> I was hoping the C-Haskell mix would work. I am glad to hear
> that you have good things to say about it.
>
Why would you like to compile C to Haskell as opposed to using FFI
(Foreign Function Interface) - i.e. calling C from Haskell or Haskell
from C?
> My main reason for thinking about the C-to-Haskell compiler was to
> address the question "Say you had a C program. Can you always convert
> it to Haskell in such a way that the compiled Haskell is not too slow
> and does not need too much memory?" Supposing that too slow means
> slower than 1/4 the speed of C and too much memory means twice the
> memory of C.
I'd say that given optimal Haskell compiler (and possibly in IO) - yes.
However we don't have optimal Haskell compiler (neither optimal C
compiler BTW) so Haskell program might be slower. Or faster (like with
combination of sorting and taking first element).
> Do you know the answer to this question?
>
> Cheers,
> Hein
>
Regards
PS. Could you limit length of line to 72-80 characters? Thank you in
advance.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 836 bytes
Desc: This is a digitally signed message part
Url :
http://www.haskell.org/pipermail/beginners/attachments/20100413/0de84e11/attachment-0001.bin
------------------------------
_______________________________________________
Beginners mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/beginners
End of Beginners Digest, Vol 22, Issue 20
*****************************************
