Hi!
While bootstrapping a ghc checked out from cvs from yesterday I ran into a
problem. While compiling PrelBase.lhs I got the following error message:
ghc-5.03: panic! (the `impossible' happened, GHC version 5.03):
coreSyn/CoreUtils.lhs:97: Non-exhaustive patterns in function
Hi again!
In order to compile the module nativeGen/MachCode.lhs I have to add
isAsmTemp to the import list of module CLabel. Currently it says:
import CLabel ( CLabel, labelDynamic )
but I change it to:
import CLabel ( CLabel, labelDynamic, isAsmTemp )
isAsmTemp is only
GHC 5.02 accepts forall types only at some sensible places:
this works
data CPS a = CPS { unCPS :: forall ans . (a - ans) - ans }
this doesn't work
newtype CPS a = CPS { unCPS :: forall ans . (a - ans) - ans }
this works
newtype CPS a = CPS (forall ans . (a - ans) -
Here's another one, using GHC 5.02
[ian@urchin current]$ cat W.lhs
module Main where
main :: IO()
main = putStrLn $ show $ last [1..10]
[ian@urchin current]$ ghc W.lhs -prof -auto-all -o W
[ian@urchin current]$ ./W +RTS -h
10
[ian@urchin current]$ ./W +RTS -c
10
Humn... I agree with both of you, Albert and Tom. I started
it from the
beginning, using map and don't using reverse anymore. But the
C program is
still 7x faster than the Haskell one. Here is the code of the Haskell
program:
main :: IO ()
main = do
bmFile - openFileEx in.txt
Simon Marlow [EMAIL PROTECTED] writes:
Well, in Haskell each character of the string takes 20 bytes: 12 bytes
for the list cell, and 8 bytes for the character itself
Why does a list cell consume as much as 12 bytes? Two pointers (data
and next) and a 32-bit tag field, perhaps? And a 64-bit
Hi all
I've been reading the GHC docs and they say that strict functions are
good for space and time. Section 6.2 goes on to explain how to read the
.hi files to determine the strictness of a function. However, it doesn't
explain all the cases I am seeing. Example of the ones I've noticed are:
Recently I've been experimenting with a sort of OOP with GHC, using existential types
and
(overlapping, undecidable) multi-parameter type classes, but it doesn't seem to work
as you
might expect because of the way GHC resolves overloaded functions at compile-time.
For example,
given class A
G'day all.
On Fri, Oct 19, 2001 at 02:30:59PM +0100, Ian Lynagh wrote:
Also, the prelude definition of zipWith has LVL whereas the following
definition has LVV. Why is something like the following not used?
zipWith :: (a-b-c) - [a] - [b] - [c]
zipWith f (a:as) (b:bs) = f
Simon Marlow [EMAIL PROTECTED] writes:
To really match the C program, you need to use IOExts.hGetBuf and
IOExts.hPutBuf, and do the operations on raw characters in memory.
Using a UArray of Word8 would be better, but there aren't any
operations to do IO to/from a UArray yet (actually I've
I am about to rewrite my Z animation tool (JAZA) in a style that
makes more intensive use of state monads.
However, my experiments with a simplified lambda-calculus example
shows that (with GHC 5.00) the state monad is dramatically less
efficient than the simple identity monad:
4 TIMES
Fri, 19 Oct 2001 17:02:54 +0200, George Russell [EMAIL PROTECTED] pisze:
So is there any other way of doing this sort of dynamic lookup at
runtime, in a reasonably neat way?
There is module Dynamic. I don't know if it helps or is reasonably
neat.
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At 2001-10-19 08:02, George Russell wrote:
a naive user (like me a month ago) might expect that this to work, so that
toBool (WrappedA a) (WrappedB b) will return False unless a is an A1, and
b a B1, in which case it returns True.
I think existential types are arranged so that Haskell never
Till Doerges writes:
select' :: [a] - [Integer] - ([a],[a])
select' xs poss = sAcc xs (sort poss) 0 ([],[])
where sAcc :: [a] - [Integer] - Integer - (([a],[a]) - ([a],[a]))
...
Crash select' test [0..]
(35922 reductions, 63905 cells)
ERROR: Control stack overflow
...
2) Why
Till Doerges writes:
I tried to implement a function that separates a list into two parts
according to a list of indices given. (Does anything like that perhaps
exist already in the Prelude?)
...
1) Could anybody please explain the behaviour of select and select'
to me?
To
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Description of the Position
A research position is available on an
Have you looked in the list library? partition or groupBy may be what you want.
Dominic.
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Hi,
I have a script here
interleave::[Integer] - [Strings]
- [String]interleave(x:xs)
(y:ys) = words [a | a -
(unwords [(show x), (filter (/= 1) y), "+"])]
and the error message i receive is
(Instance of Num Char required for definition of
interleave)
and I don't understand what this
Stephanie == Stephanie Randles [EMAIL PROTECTED] writes:
Stephanie Hi, I have a script here
Stephanie interleave :: [Integer] - [Strings] - [String]
Stephanie interleave (x:xs) (y:ys) = words [a | a - (unwords
Stephanie [(show x), (filter (/= 1) y), +])]
Stephanie and the
Simon Marlow [EMAIL PROTECTED] writes:
Well, in Haskell each character of the string takes 20 bytes: 12 bytes
for the list cell, and 8 bytes for the character itself
Ahem, _Haskell_ mandates no such thing. Perhaps you are talking
about a specific implementation? ghc probably.
Isn't it
Hello,
Hi,
I have a script here
interleave :: [Integer] - [Strings] -
[String]
interleave (x:xs) (y:ys)
= words [a | a - (unwords
[(show x), (filter (/= 1) y), +])]
Firstly, Strings is not a standard type. I suspect
you mean String so the type signature is
interleave :: [Integer] - [String]
19 Oct 2001 06:09:09 +0100, Colin Paul Adams [EMAIL PROTECTED] pisze:
But this seems to assume there is a one-to-one mapping of upper-case
to lower-case equivalent, and vice-versa. Apparently this is not so.
Indeed, but there exists a default locale-independent case mapping.
Language-specific
Hi everybody,
thanks for all the answers!
On Fri, Oct 19, 2001 at 09:55:00AM +0200, Janis Voigtlaender wrote:
[...]
You might try the following version that does not build up huge data
structures in accumulating parameters to output them only in the two
base cases. Rather, it produces
Has anyone made a program for Hugs that allows you to add type definitions
and top level functions to the Main module from the interpreter command
line? I find it odd that I have load from a text file to experiment with
data types, classes, etc. If this sort of thing is not available convince
me
An apparently-innocuous suggestion about adding default methods for
sinh and cosh led to a flood of mail. Since no consensus emerged, I
plan to leave things as they are in the Haskell 98 Report. Namely,
the following default methods for the Floating class are there:
x**y = exp (log x
Jerzy Karczmarczuk wrote:
Brian Boutel to Sergey Mechveliani:
There is no scientific reason why all computations with types and
type resolution should preceed all computations with non-types.
No scientific reason, but a strong engineering reason.
The engineering idea is to
Hi,
I am wondering why this function should not work with input [x,y]
(list with two elements) too, since third element is not referenced. Why
is it so eager to pattern match.
fun = \list - let [a,b,c] = list
in [a,b]
Thanks,
Saswat
Sat, 20 Oct 2001 10:58:02 +0800 (GMT-8), Saswat Anand [EMAIL PROTECTED] pisze:
I am wondering why this function should not work with input [x,y]
(list with two elements) too, since third element is not referenced.
What a pattern matches is independent from which of the variables
it binds
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