This array is for dynamic programming.
You can diagonalize it into a list and use technique similar to the
Fibonacci numbers.
The resulting solution should be purely declarative.
2012/12/11 mukesh tiwari mukeshtiwari.ii...@gmail.com:
Hello All
I am trying to transform this C++ code in
If you're trying to memoize a recursive algorithm with a global array of
previous states, you could use the marvellous MemoTrie package [1]. It lets
you write your algorithm recursively, while getting all the benefits of
memoization! Here's an example with the fibonacci function:
fib :: Int -
I have written a C++ parser in Scheme, with a Parsec-style parser
combinator library. It can parse a large portion of C++ and I use it
to do structural comparison between ASTs. I made some macros so that
the parser combinators look like the grammar itself.
It's code is at:
On Wed, Feb 1, 2012 at 12:42 PM, Yin Wang yinwa...@gmail.com wrote:
I have written a C++ parser in Scheme, with a Parsec-style parser
combinator library. It can parse a large portion of C++ and I use it
to do structural comparison between ASTs. I made some macros so that
the parser combinators
I haven't dealt explicitly with templates. I treat them as type
parameters (element $type-parameter). I don't check that they have
been declared at all. As explained, these are semantic checks and
should be deferred until type checking stage ;-)
Cheers,
Yin
On Wed, Feb 1, 2012 at 4:07
On Tue, Jan 24, 2012 at 4:06 AM, Christopher Brown
cm...@st-andrews.ac.uk wrote:
Hi,
I have stumbled across language-c on hackage and I was wondering if anyone is
aware if there exists a full C++ parser written in Haskell?
I'm not aware of one.
When it comes to parsing C++, I've always
On 24 Jan 2012, at 11:06, Christopher Brown wrote:
I have stumbled across language-c on hackage and I was wondering if anyone is
aware if there exists a full C++ parser written in Haskell?
There is a yaccable grammar
On Tue, Jan 24, 2012 at 2:06 AM, Christopher Brown
cm...@st-andrews.ac.uk wrote:
Hi,
I have stumbled across language-c on hackage and I was wondering if anyone is
aware if there exists a full C++ parser written in Haskell?
I don't think one exists. I've heard it's quite difficult to get
Hi Everyone,
Thanks for everyone's kind responses: very helpful so far!
I fully appreciate and understand how difficult writing a C++ parser is.
However I may need one for our new Paraphrase project, where I may be targeting
C++ for writing a refactoring tool. Obviously I don't want to start
On Tue, Jan 24, 2012 at 6:54 AM, Christopher Brown
cm...@st-andrews.ac.uk wrote:
Hi Everyone,
Thanks for everyone's kind responses: very helpful so far!
I fully appreciate and understand how difficult writing a C++ parser is.
However I may need one for our new Paraphrase project, where I
Hi Jason,
Thanks very much for you thoughtful response.
I am intrigued about the Happy route: as I have never really used Happy before,
am I right in thinking I could take the .gr grammar, feed it into Happy to
generate a parser, or a template for a parser, and then go from there?
Chris.
On Tue, Jan 24, 2012 at 8:40 AM, Christopher Brown
cm...@st-andrews.ac.uk wrote:
Hi Jason,
Thanks very much for you thoughtful response.
I am intrigued about the Happy route: as I have never really used Happy
before, am I right in thinking I could take the .gr grammar, feed it into
Happy
On Tue, Jan 24, 2012 at 2:06 AM, Christopher Brown
cm...@st-andrews.ac.ukwrote:
I have stumbled across language-c on hackage and I was wondering if anyone
is aware if there exists a full C++ parser written in Haskell?
Check out clang: http://clang.llvm.org/ and
There is also the DMS from Ira Baxter's company Semantic Design's.
This is an industry proven refactoring framework that handles C++ as
well as other languages.
I think the Antlr C++ parser may have advanced since the article
Antoine Latter link to, but personally I'd run a mile before trying to
Hi all,
Just to add to the list - Qt Creator contains a pretty nice (and
incremental) C++ parser.
Cheers,
Dave
On Wed, Jan 25, 2012 at 5:06 AM, Stephen Tetley stephen.tet...@gmail.comwrote:
There is also the DMS from Ira Baxter's company Semantic Design's.
This is an industry proven
2012/1/22 Данило Глинський abcz2.upr...@gmail.com
What is natural Haskell representation of such enum?
enum TypeMask
{
UNIT,
GAMEOBJECT,
CREATURE_OR_GAMEOBJECT = UNIT | GAMEOBJECT
};
I don't think that definition makes any sense in C, because UNIT is 0, so UNIT
| GAMEOBJECT
Thanks. This and previous email are answers to question I asked. But not
the answer to question I mean.
I'll describe the whole task, as Yves Parès suggested.
I'm trying to convert C++ code to Haskell. I have such hierarchy: class
Object, class Item : Object, class Container : Item. Another one
If you want a simple translation, use Word8 (from Data.Word) for the type
and use Data.Bits for operations on it just like in C++. This would offer
you storage efficiency (if stored as a strict field).
If you want idiomatic Haskell, constructor of the form:
data ObjectType = Object | Item |
On 2012-01-23 13.45.50 -0800, David Barbour wrote:
If your classes are more like `interfaces`, you could use Typeclasses to
model them. Otherwise, look into OOHaskell. But I think your program
architecture will simply be different in idiomatic Haskell than in
idiomatic C++.
If your OO is very
Performing bit-mask operations is possible via the Data.Bits operations (on
elements of type Word8 or Word16, etc.). But I must say, it doesn't seem
very `natural` in Haskell, nor even in other languages. It crosses lines,
binding abstraction to representation in order to improve efficiency.
The
Данило Глинський wrote:
What is natural Haskell representation of such enum?
enum TypeMask
{
UNIT,
GAMEOBJECT,
CREATURE_OR_GAMEOBJECT = UNIT | GAMEOBJECT
};
data ObjectType = Unit | GameObject
creatureOrGameObject :: ObjectType - Bool
creatureOrGameObject Unit = True
I may be curious to see how you intend to use such enum...
It is very C-wise, I'm not sure it will be very handy, but I need some
context.
2012/1/22 Данило Глинський abcz2.upr...@gmail.com
What is natural Haskell representation of such enum?
enum TypeMask
{
UNIT,
GAMEOBJECT,
On 5 jul 2010, at 23:48, Yves Parès wrote:
Hello,
I don't know if some of you are familiar with the SFML library (stands for
Simple and Fast Multimedia Library) -- http://sfml-dev.org
As SDL, SFML is a 2D graphics library, but conversely to SDL it provides a
hardware-accelerated drawing,
That's indeed an advice I've read [1].
But wouldn't it damage the performances, since code will have to go through
an extra layer?
[1] http://blog.ezyang.com/2010/06/principles-of-ffi-api-design
2010/7/7 Chris Eidhof ch...@eidhof.nl
On 5 jul 2010, at 23:48, Yves Parès wrote:
Hello,
I
Making an immutable API from a mutable one generally damages
performance (on von neumann architectures) somewhat, the goal is to
minimize that impact.
Cheers.
~Liam
On 7 July 2010 19:40, Yves Parès limestr...@gmail.com wrote:
That's indeed an advice I've read [1].
But wouldn't it damage the
I think it might influence performance, but it doesn't have to be that much.
There are some optimization tricks you can apply to deal with this. Premature
optimization is the root of all evil ;)
-chris
On 7 jul 2010, at 11:40, Yves Parès wrote:
That's indeed an advice I've read [1].
But
2010/7/7 Liam O'Connor lia...@cse.unsw.edu.au
Making an immutable API from a mutable one generally damages performance
(on von neumann architectures) somewhat, the goal is to minimize that
impact.
In fact, I would like to determine if an EFFICIENT way to make images and
such immutable exists,
On Wed, Jul 7, 2010 at 2:24 PM, Yves Parès limestr...@gmail.com wrote:
2010/7/7 Liam O'Connor lia...@cse.unsw.edu.au
Making an immutable API from a mutable one generally damages performance
(on von neumann architectures) somewhat, the goal is to minimize that
impact.
In fact, I would
Okay,
so I think that the better idea is to carry on with my low-level, imperative
binding, and then build a more functional on top of this.
Concerning the mutability of images, I notice that the problem with SFML is
that it handles Sprites in a way that is even more imperative than OpenGL
To answer the question in your subject, “Very Carefully.”
While I don’t know much about your particular problem domain (and it seems
others have given useful advice), I can say some general things about
making mutable things immutable.
There is a very simple way to make something mutable
On 07/05/2010 04:48 PM, Yves Parès wrote:
3) Is there another library on hackage that handles images in a
functional way? (I mean not /all in IO/)
Check out graphics-drawingcombinators.
- Jake
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On Tue, Apr 20, 2010 at 8:48 AM, Tom Hawkins tomahawk...@gmail.com wrote:
I have a bunch of global variables in C I would like to directly read
and write from Haskell. Is this possible with FFI, or must I write a
bunch of C wrapper functions for the interface, i.e. a 'get' and a
'set' for
Tom Hawkins wrote:
I have a bunch of global variables in C I would like to directly read
and write from Haskell. Is this possible with FFI,
Yes it is, as explained in section 4.1.1. in the FFI specification [1].
An import for a global variable int bar would look like this:
foreign
On Tue, Apr 20, 2010 at 01:48:16AM -0500, Tom Hawkins wrote:
I have a bunch of global variables in C I would like to directly read
and write from Haskell. Is this possible with FFI, or must I write a
bunch of C wrapper functions for the interface, i.e. a 'get' and a
'set' for each variable?
2010/1/29 Maurício CA:
Sorry if this looks weird, but do you know of experiences with
functional programming, or type programming, with C? Using macro
tricks or just good specifications?
This is probably not what you're looking for, but it's related:
Single-Assignment C (Functional Array
On Jan 29, 2010, at 9:11 AM, Maurí cio CA wrote:
Sorry if this looks weird, but do you know of experiences with
functional programming, or type programming, with C? Using macro
tricks or just good specifications?
I know this is not absurd to a small extent. I've heard of proof
tool
Maurício CA wrote:
Hi, all,
Sorry if this looks weird, but do you know of experiences with
functional programming, or type programming, with C? Using macro
tricks or just good specifications?
I know there is some type level programming (not strictly functional)
in CCAN:
On Wed, 2009-10-28 at 17:34 -0200, Maurício CA wrote:
Hi,
I've been using 'install-includes' in a package. I sometimes make
small changes to those include files, and I've seen that cabal
doesn't consider then dependencies, i.e., doesn't rebuild .hsc
files depending on then.
I'm not sure
I need anyones experience.
Possibly this old post of mine can help:
http://therning.org/magnus/archives/315
Oh...
WHile i was trying to repeat after you, it's become clear to me that
this is not actually what I want.
I want to create some structure, say
data WM = WM {some_info ::
On 13/11/09 05:31, Vasiliy G. Stavenko wrote:
Hello everyone.
What about passing complex c-types (structures) to c-functions.
More detailed: I have an application in production which was written in
Delphi. IT has ability to create pluggable modules to it. Interface
realized by sending
On Wed, Jan 28, 2009 at 04:42:49PM -0800, drblanco wrote:
Here's my attempt, which takes about 75s for r=10^8.
circ2 r = (1+4*r) + 4 * (circ2' (rs+1) r 1 0)
where
rs = r^2
circ2' rad x y sum
| xy = sum
| rad=rs =
I had a quick look at the code for
loop :: Int64 - Int64 - Int64
loop i r = if i == 0 then r else loop (i-1) (r+1)
It's quite bad. It's full of C calls.
It would be much better to do what gcc does and treat Int64 as a
primitive type, and just insert C calls for the tricky operations,
like
On Wed, 2009-01-28 at 16:42 -0800, drblanco wrote:
I do already have the number I wanted, but was wondering how this could be
made faster, or even why it's so slow. This is all on GHC 6.8.3 under OS X
Intel, using ghc -O2.
I'm not exactly sure what's different, but for me it works pretty
Did you print it? I'm using same code with ghc --make -O2 and it
takes forever to finish.
On Wed, Jan 28, 2009 at 8:06 PM, Duncan Coutts
duncan.cou...@worc.ox.ac.uk wrote:
On Wed, 2009-01-28 at 16:42 -0800, drblanco wrote:
I do already have the number I wanted, but was wondering how this
On Wed, 2009-01-28 at 20:11 -0500, sam lee wrote:
Did you print it? I'm using same code with ghc --make -O2 and it
takes forever to finish.
Yes, you can see in the output that it prints the same answer in each
case. I was using r = 10^9 as you suggested.
C version:
$ time ./circ
Duncan, I think you must have some magics -- on my machine the
original code also takes forever.
Running with +RTS -S indicates it's allocating several gig of memory
or more.
Applying some bang patterns gives me ~8s for 10^8 and somewhat more
than a minute for 10^9:
{-# LANGUAGE
On Wed, 2009-01-28 at 20:23 -0500, Ross Mellgren wrote:
Duncan, I think you must have some magics -- on my machine the
original code also takes forever.
Running with +RTS -S indicates it's allocating several gig of memory
or more.
It runs in a tiny heap for me:
./circ2 +RTS -A10k -M20k
Thanks for the help. It's clear in retrospect that it was being too
lazy, but not why changing to Int64 did it. The bang patterns made
the difference between runnable and not.
GHC 6.10 didn't make much of a difference, but there's no 64-bit build
for the Mac. If this seems to come up again
Ross Mellgren wrote:
Duncan, I think you must have some magics -- on my machine the original
code also takes forever.
Running with +RTS -S indicates it's allocating several gig of memory or
more.
Applying some bang patterns gives me ~8s for 10^8 and somewhat more than
a minute for 10^9
It
Apparently 64-bit GHC is sufficiently advanced to be indistinguishable
from magic. Now, if only there was a 64-bit binary for Mac OS X :-/
-Ross
On Jan 28, 2009, at 9:06 PM, Jake McArthur wrote:
Ross Mellgren wrote:
Duncan, I think you must have some magics -- on my machine the
original
On Wed, 2009-01-28 at 20:42 -0500, Ross Mellgren wrote:
Very possibly -- I'm on a mac so no prebuilt 64-bit binary. I'm not
good enough at reading core to tell, but I can tell from the core that
it's calling out to external C functions to do the 64-bit math.
Right, that'll make it really
Evan Laforge wrote:
To threadjack a little bit, I've been interfacing haskell with c++.
It gets awkward when the c++ structures use STL types like string and
vector. Of course those are too complex for haskell to marshal to.
What I've been doing is defining an XMarshal variant of the X c++
you mean, you hack around with the internal representation of those
structures? Well, if you want to avoid double-copying, C++ can't access
Haskell sequences, and Haskell can't access C++ sequences, I guess I don't
see an alternative.
I don't really mind double copying, but having to
you could write a C++ function to marshal a Sequence (or any Container
IIRC, maybe Forward Container) to a vector (or whatever you wanted --
there are choices), and then
okay let's see if I remember C++ well enough
This design has extra copying. but anyway
templatetypename Container
Although you could use gcc to link the code I wouldn't recommend it
(mainly for the problems you are currently having)
SImply call GHC to compile both the C and Haskell code. It will take
care of finding the headers and supplying the necessary linker
arguments.
ghc -ffi -c foo.hs myfoo_c.c
Thanks,
I found on one site how to compile after creating the stub files with GHC:
First step:
*ghc -c -ffi haskell_file.hs*
Second step - here it is important to know and write where are the ghc
libraries:
*gcc -I /usr/local/lib/ghc-5.04.3/include -c C_file.c *
After that it is important to
if you'd normally be linking using g++, you'll need (IIRC) -lstdc++
added to linking-ghc's command line
Alfonso Acosta wrote:
Although you could use gcc to link the code I wouldn't recommend it
(mainly for the problems you are currently having)
SImply call GHC to compile both the C and
Well Isaac...I became now a little bit smarter then yesterday!!!
I show you the example that I found and on which I´m working with.
File: foo.hs
module Foo where
foreign export ccall foo :: Int - IO Int
foo :: Int - IO Int
foo n = return (length (f n))
f :: Int - [Int]
f 0 = []
f n = n:(f
write the C wrapper that calls haskell, then link that to your C++ objects
I think what you're really asking is how to call C from C++
-Dan
2008/4/16 Miguel Lordelo [EMAIL PROTECTED]:
Hi all,
Well...somehow I'm a beginner in Haskell. But actually my interest in
Haskell will increase if it
perhaps
haskell:
foreign export foo_func foo :: Int - IO Int
-- I forget the rest of the syntax here
C++:
extern C {
int foo_func(int i);
}
int some_cplusplus_function() {
int bat = 3;
int blah = foo_func(bat);
return blah;
}
Is that all you need to do?
Miguel Lordelo wrote:
Hi
I was mainly specifically comparing haskell to standard OOP classes,
Most OOP languages certainly have some set of other features in addition,
such as forms of ad hoc polymorphism or the template meta-language of
C++, or the code reuse primitives in sather, however I was mainly
interested in
On 8/20/06, John Meacham [EMAIL PROTECTED] wrote:
C++ templates are a whole nother ball of wax.
And that's putting it politely. ;-)
T.
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John Meacham [EMAIL PROTECTED] writes:
| I was mainly specifically comparing haskell to standard OOP classes,
|
| Most OOP languages certainly have some set of other features in addition,
| such as forms of ad hoc polymorphism or the template meta-language of
| C++, or the code reuse primitives
John Meacham [EMAIL PROTECTED] writes:
| On Tue, Aug 15, 2006 at 08:36:28PM +0200, Gabriel Dos Reis wrote:
| Roughly Haskell type classes correspond to parameterized abstract
| classes in C++ (i.e. class templates with virtual functions
| representing the operations). Instance declarations
Bulat Ziganshin [EMAIL PROTECTED] writes:
| Hello John,
|
| Friday, August 18, 2006, 5:16:45 AM, you wrote:
|
| There is a major difference though, in C++ (or java, or sather, or c#,
| etc..) the dictionary is always attached to the value, the actual class
| data type you pass around. in
Hello John,
Friday, August 18, 2006, 5:16:45 AM, you wrote:
There is a major difference though, in C++ (or java, or sather, or c#,
etc..) the dictionary is always attached to the value, the actual class
data type you pass around. in haskell, the dictionary is passed
separately and the
Bulat Ziganshin wrote:
http://haskell.org/haskellwiki/OOP_vs_type_classes
although i mentioned not only pluses but also drawbacks of type
classes: lack of record extension mechanisms (such at that implemented
in O'Haskell) and therefore inability to reuse operation
implementation in an derived
On 8/18/06, John Meacham [EMAIL PROTECTED] wrote:
[lots of good argument before and after deleted]
There is a major difference though, in C++ (or java, or sather, or c#,
etc..) the dictionary is always attached to the value, the actual class
data type you pass around. in haskell, the
On Wed, Apr 19, 2006 at 11:01:03PM +0200, Christophe Poucet wrote:
For the parsing and lexing I used happy and alex.
Jake Luck wrote:
I would be very interested in this as well. I have looked myself but
haven't found anything else. I wrote one myself in Haskell but for a
subset of C++
I would be very interested in this as well. I have looked myself but
haven't found anything else. I wrote one myself in Haskell but for a
subset of C++ (subset of C but with some extra things like methods).
Christophe Poucet
Ravi Nanavati wrote:
It turns out we might find such a beast
I would be very interested in this as well. I have looked myself but haven't
found anything else. I wrote one myself in Haskell but for a subset of C++
(subset of C but with some extra things like methods).
Did you build it using parsec or happy? jake
For the parsing and lexing I used happy and alex.
Jake Luck wrote:
I would be very interested in this as well. I have looked myself but
haven't found anything else. I wrote one myself in Haskell but for a
subset of C++ (subset of C but with some extra things like methods).
Did you build it
Hi,
The Foreign Function Interface (FFI) is your friend for these tasks:
http://www.cse.unsw.edu.au/~chak/haskell/ffi/
On the haskell.org web page, under libraries and tools there are
links to
a number of tools to help you connect your C haskell programs.
The GreenCard and c-haskell tools
It's not really newbie stuff, but maybe this is what you're looking for:
http://www.cse.unsw.edu.au/~chak/haskell/ffi/
#g
--
At 09:56 13/04/04 -0700, Russ Lewis wrote:
Does Haskell have some mechanism that allows it to link to C, or other
imperative languages?
I know, you could use the IO
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