On Thu, 14 Aug 2003, blaat blaat wrote:
To many questions, not enough mail. First, thanks for all your replies.
Second, I stand totally corrected on the fact that we cannot break down
monads. Functions of type m a-b are called impure,
Haskell is a pure language, so there are *no* impure
On 26 Sep 2002, Yoann Padioleau wrote:
Koen Claessen [EMAIL PROTECTED] writes:
i find your idea very good.
indeed for the library GetOpt, the argument of a program never change so it
make sense to make this library without using IO monad, same for argv and for the
enviroment.
for
On 26 Sep 2002, Yoann Padioleau wrote:
Koen Claessen [EMAIL PROTECTED] writes:
i find your idea very good.
indeed for the library GetOpt, the argument of a program never change so it
make sense to make this library without using IO monad, same for argv and for the
enviroment.
for
On Thu, 17 Jan 2002, Christian Schuhegger wrote:
buildIOList :: [a] - IO [a]
buildIOList li = return li
main = do {li - buildIOList [1..];
putStr (show (take 1 li));
}
I take it you know that
do li - buildIOList [1..]
...
is equal to
do
On Mon, 26 Feb 2001, Martin Gustafsson wrote:
Hello
I'm a haskell newbie that tries to create a tree with arbitary numbers of childs.
I create the data structure but i can't do anything on it can someone please help
me with a small function that sums the values of the leafs, so i dont
On 23 Feb 2001, Julian Assange wrote:
Is there a standard construct for something of this ilk:
unliftM :: Monad m a - a
I do not know if it is a standard, but every monad usually has a
"runMonad" function. For ST you have runST, for IO you have
unsafePerformIO and for your own monad
On Sat, 17 Feb 2001, Ken Shan wrote:
On 2001-02-16T09:52:41+0100, Lars Lundgren wrote:
This is ad hoc overloading, and IMHO bad style, at least in haskell. As I
understand it, haskell type classes were never intended to support this.
Well, whether this is ad hoc overloading depends
On Wed, 3 Jan 2001, Michael Zawrotny wrote:
1. How the #$!? do I read some data from a file. Good, I've
got the data, now I can work on it. Nope, now I have an "IO
thingie" whatever that is, but all of the standard functions want
a regular "thingie" now what?
I do not know if you
On Fri, 27 Oct 2000, Matthias Höchsmann wrote:
Hello,
I have the following problem:
basic datatypes
type Sequence a = [a]
data Tree a = N a (Forest a) deriving (Ord,Eq,Show)
type Forest a = Sequence (Tree a)
i want to construct a class Xy
class Xy s a where
test :: s
On Wed, 18 Oct 2000, Scott Turner wrote:
Is there a common way to pronounce "=" in discussions or when teaching?
I've learned all my Haskell from printed/visual documents.
How about 'bind'? and "" = 'then'.
/Lars L
___
Haskell mailing list
On 19 May 2000, Ketil Malde wrote:
Frank Atanassow [EMAIL PROTECTED] writes:
I agree, and I think it's hopeless. This is my last message to the Haskell
list on the subject. There is nothing Haskell-specific any longer about this
discussion.
Uh, I feel I'm a bit of a hobbyist on this
On Tue, 16 May 2000, Jan Brosius wrote:
Ok I understand this isomorphism better. However this remark seems to be of
no value to functional programmers.
Why trying to mix terms( otr types) with relations ?
What is a 'type' in your oppinion?
Isn't a type a statement about pre- and
On Thu, 11 May 2000, Jan Brosius wrote:
Marcin Kowalczyk wrote at Wed, May 10, 2000 7:54 PM :
Types can be treated as logical formulas, according to the Curry-Howard
isomorphism.
Sorry, never heard of in logic. But perhaps you can explain.
M H Sørensen and P Urzyczyn.
Lectures on
On 26 Apr 2000, Friedrich Dominicus wrote:
This question may sound a bit strange. I'll try to explain. I have
written a piece of Haskell and found that I did not understand
things. I tried to look what I got wrong and searched for a
possibility to give me output. Now obvious is that Haskell
On Wed, 26 Apr 2000, Hamilton Richards wrote:
The Gofer prelude had a function
openfile :: String - String
which mapped file path names to strings containing the named files' contents.
The Hugs98 Prelude doesn't seem to have anything like that function.
Instead, it has things
On Sat, 25 Mar 2000, T. D. Stones wrote:
Hello there
I am A 3rd year student at Leicester Uni, and I am doing my project
using Hugs 1.4. I've noticed that things like EOF
What is it you want to do with EOF?
(I need to read a file
aha, so why dont you use readFile :: FilePath - IO
On Wed, 9 Feb 2000, Stefan Friedel wrote:
Hi everybody, I have a problem. I'm new to haskell and
I have to write a function that takes the following
list and finds the average by using recursion and
adding the numbers together. I'm completely STUCK!
Thank you.
sales :: Int - Float
On Mon, 6 Dec 1999, c_stanto wrote:
here is my code and I am guess that the problem is that openFile returns
an IO Handle and getContents takes just a Handle. How do I go about
fixing this?
module Main(main) where
import IO
main = putStrLn (getContents (openFile "./joseph.txt"
On Mon, 11 Oct 1999, Adrian Hey wrote:
On Mon 11 Oct, Lars Lundgren wrote:
I'm sure a lot of poeple have gotten this wrong. I would be surprised if
not all the experienced haskellers has this view though.
Probably so, but this view seems in complete contradiction to
that of the Clean
On Fri, 8 Oct 1999, Adrian Hey wrote:
On Fri 08 Oct, Lars Lundgren wrote:
A value (IO a) *denotes* a program possibly interacting with the world.
*That* program is of course not referentially transparent. A haskell
program generating an (IO a) on the other hand *is* referetially
On Thu, 7 Oct 1999, Adrian Hey wrote:
On Thu 07 Oct, Manuel M. T. Chakravarty wrote:
Check out the type signatures of the `MVar'-related
operations and you will find that they are all nicely
encapsulated in the `IO' monad.
This is true, but I think the point of contention is does the
On Tue, 28 Sep 1999, S. Alexander Jacobson wrote:
My simple point is that claims about the correctness or incorrectness of
the behavior of a function are incoherent outside the function's domain;
that, as an language implementation matter, it is handy to make _|_ a
member of all types is
On Thu, 16 Sep 1999, Lars Lundgren wrote:
[snip]
myProg:: StateMT IO Int
myProg = return 5
main = do n - runSMT myProg
print n
I forgot to show something interesting in my first example, try this
instead:
myProg:: StateMT IO Int
myProg = do lift $ putStrLn "Hello
On Thu, 9 Sep 1999, George Russell wrote:
Here is my revised version of the documentation. Sorry I can't
manage the pretty formatting:
unzip :: [(a,b)] - ([a],[b])
-
Description:
unzip takes a list of pairs and returns a pair of lists.
Examples:
unzip [(1,2),(3,4),(5,6)]
On Mon, 16 Aug 1999, Keith Wansbrough wrote:
Hi all... has anyone implemented the Union-Find algorithm in Haskell?
I've looked at the various libraries listed at haskell.org and found
nothing, but don't want to re-invent the wheel if someone else has done
it already.
Hmm, yes I have
On Mon, 16 Aug 1999, Keith Wansbrough wrote:
Hi all... has anyone implemented the Union-Find algorithm in Haskell?
I've looked at the various libraries listed at haskell.org and found
nothing, but don't want to re-invent the wheel if someone else has done
it already.
Yes I have. I
On Mon, 14 Jun 1999, Jose Bernardo Barros wrote:
According to the definition of the class Bounded, minBound and maxBound
have types
minBound :: Bounded a = a
maxBound :: Bounded a = a
Suppose I define the function
f (minBound, maxBound) = (maxBound, minBound)
On Wed, 9 Jun 1999, Friedrich Dominicus wrote:
[snip]
What's a HOF?
A Higher Order Function, the key to code reuse and abstraction.
that first splits something up to a list using splitFn
(or with the generalization I mentioned, to a monad), then maps a
function over that list (namely
On 16 Feb 1999, Carl R. Witty wrote:
Lars Lundgren [EMAIL PROTECTED] writes:
We have already accepted undecidable type checking, so why not take a
big step forward, and gain expressive power of a new magnitude, by
extending the type system to allow dependent types.
Wait a minute
The trend seems to be define wishes for haskell 2, so here are mine:
We have already accepted undecidable type checking, so why not take a
big step forward, and gain expressive power of a new magnitude, by
extending the type system to allow dependent types.
Cayenne,
On Fri, 5 Nov 1999, Dusan Kolar wrote:
Hi,
Could anyone, please, give me reference to or a sophisticated
answer?
I am going to have maybe a very stupid question.
Well. it's definitely a FAQ.
Playing with IO monads I made to me a task. Create
a function which counts lines of a
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