On Sun, 13 May 2007, Stefan Holdermans [EMAIL PROTECTED] wrote:
Anyway, Conor and James' Haskell Workshop paper on manipulating
syntax that involves both free and bound variables [1] is really nice
and could perhaps be of interest to you.
If I remember correctly this paper is not about a pure
Nils,
Anyway, Conor and James' Haskell Workshop paper on manipulating
syntax that involves both free and bound variables [1] is really nice
and could perhaps be of interest to you.
If I remember correctly this paper is not about a pure de Bruijn index
representation, but about a mix between
Stefan Holdermans wrote:
This is rather typical in the field of program analysis. Getting the
analysis precise is impossible and reduces to solving the halting
problem. So, the next best thing is to get an approximate answer. An
import design guideline to such an analysis is to err on the safe
Hi,
{-# OPTIONS_GHC -fglasgow-exts #-}
class F a b | b - a where
data G :: * - * where
GC :: (F a b) = a - G b
foo :: (F a b) = G b - a
foo g = case g of
(GC a) - a
I may be being dumb, but I think this should work. Any value of G
using the GC constructor will be
Andrew,
Right. So what you're saying is that for most program properties,
you can partition the set of all possible problems into the set for
which X is true, the set for which X is false, and a final set for
programs where we can't actually determine the truth of X. Is that
about right?
I noticed recently that the website of CUFP conference (Commercial Uses of
Function Programming), which used to be at http://www.galois.com/cufp,
is not accessible anymore.
Does anybody know where it moved?
Cyril
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Anyway, Conor and James' Haskell Workshop paper on manipulating
syntax that involves both free and bound variables [1] is really nice
and could perhaps be of interest to you.
If I remember correctly this paper is not about a pure de Bruijn index
representation, but about a mix between names and
Andrew Coppin wrote:
Right. So what you're saying is that for most program properties, you
can partition the set of all possible problems into the set for which X
is true, the set for which X is false, and a final set for programs
where we can't actually determine the truth of X. Is that about
On Fri, 11 May 2007, Malcolm Wallace wrote:
*Text.ParserCombinators.PolyLazy
runParser (exactly 4 (satisfy Char.isAlpha)) (abc104++undefined)
(*** Exception: Parse.satisfy: failed
This output is exactly correct. You asked for the first four characters
provided that they were
On 5/14/07, Roberto Zunino [EMAIL PROTECTED] wrote:
Also, using only rank-1:
polyf :: Int - a - Int
polyf x y = if x==0 then 0
else if x==1 then polyf (x-1) (\z-z)
else polyf (x-2) 3
Here passing both 3 and (\z-z) as y confuses the type inference.
Actually, I tried
I am new to Haskell---and also to languages with the off-side
rule--and working my way through Hal Daume's tutorial. I'm a little
confused by the support for code layout in Emacs' haskell-mode. Is it
buggy, or am I doing something wrong.
For example, here's the Hello, world example from the
Henning Thielemann [EMAIL PROTECTED] wrote:
*Text.ParserCombinators.PolyLazy
runParser (exactly 4 (satisfy Char.isAlpha))
(abc104++undefined)
(*** Exception: Parse.satisfy: failed
How can I rewrite the above example that it returns
(abc*** Exception: Parse.satisfy:
On Mon, May 14, 2007 at 12:47:02PM +0100, Matthew Sackman wrote:
{-# OPTIONS_GHC -fglasgow-exts #-}
class F a b | b - a where
data G :: * - * where
GC :: (F a b) = a - G b
foo :: (F a b) = G b - a
foo g = case g of
(GC a) - a
And just to confirm, this is
Christopher L Conway wrote:
The inference assigns y the type (t1 - t1) even though it is assigned
the value 3?
Yes, because type classes are open, and maybe you will demonstrate some
way to make t1-t1 an instance of Num.
Note the Num (t1 - t1) constraint in the type...
On Mon, 14 May 2007, Malcolm Wallace wrote:
Perhaps I should just rewrite the 'exactly' combinator to have the
behaviour you desire? Its current definition is:
exactly 0 p = return []
exactly n p = do x - p
xs - exactly (n-1) p
return
Roberto Zunino:
Here passing both 3 and (\z-z) as y confuses the type inference.
Christopher L Conway:
polyf :: forall a t1 t.
(Num (t1 - t1), Num a, Num t) =
a - (t1 - t1) - t
The inference assigns y the type (t1 - t1) even though it is assigned
the value 3?
Almost. It assigns y the
Christopher L Conway wrote:
On 5/14/07, Roberto Zunino [EMAIL PROTECTED] wrote:
Also, using only rank-1:
polyf :: Int - a - Int
polyf x y = if x==0 then 0
else if x==1 then polyf (x-1) (\z-z)
else polyf (x-2) 3
Here passing both 3 and (\z-z) as y confuses the type
On Mon, 14 May 2007, Malcolm Wallace wrote:
Essentially, you need to return a constructor as soon as you know that
the initial portion of parsed data is correct. Often the only sensible
way to do that is to use the 'apply' combinator (as shown in the
examples above), returning a constructor
The CUFP website is working again now.
http://cufp.galois.com/
Thanks for pointing it out.
Simon
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Matthew Brecknell wrote:
Roberto Zunino:
Here passing both 3 and (\z-z) as y confuses the type inference.
So the type inference is not really confused at all. It just gives a
not-very-useful type.
Yes, you are right, I didn't want to involve type classes and assumed
3::Int. A better
Georg Sauthoff wrote:
Simon Marlow [EMAIL PROTECTED] wrote:
Hi,
Georg Sauthoff wrote:
I am a bit unhappy with the link time of the project (i.e. the time ghc
needs to link everyting).
The project consinst of ~60 Haskell and ~25 foreign files.
[..]
Make sure everything being linked is on
Henning Thielemann [EMAIL PROTECTED] wrote:
exactly 0 p = return []
exactly n p = do x - p
xs - exactly (n-1) p
return (x:xs)
Is there a difference between 'exactly' and 'replicateM' ?
With this definition, clearly not. But when
Hi Christopher,
I have also noticed that haskell-mode (and indeed Haskell) can be finicky
sometimes. I usually put module [Name] where all on the same line and
leave imports on the left margin, so I hadn't experienced the first
problem you mentioned. However, I do notice that if I re-arrange
On 14/05/07, Christopher L Conway [EMAIL PROTECTED] wrote:
For example, here's the Hello, world example from the tutorial, with
the indentation induced by pounding Tab in haskell-mode.
test.hs:
module Test
where
import IO
main = do
putStrLn Hello, world
Prelude :l test
[1 of 1]
On 5/14/07, David House [EMAIL PROTECTED] wrote:
You should install 2.3 from the haskell-mode page [1]. Isaac Jones,
maintainer of the Debian haskell-mode package has been contacted in
order to get the latest version in the Debian repository, so it should
happen soon, but in the mean time you
Nick Meyer wrote:
main = do putStrLn Enter a number:
inp - getLine
let n = read inp
if n == 0
then putStrLn Zero
else putStrLn NotZero
(that's with all the expressions in the do block lining up vertically, if
that doesn't show up in a fixed-width
[Relocated to haskell-cafe]
Dirk Kleeblatt wrote:
apfelmus wrote:
Note that even currently, your operations cannot be strict in the
address a label refers to because this may be determined later than the
first use of the label. In other words, your example code
fac = do
[...]
(1) jmp
Hello,
I am trying to learn haskell , but i am struggling with types , its
been around 7 days , it will be very kind if some explain it why this
error , i think this is the only stumbling block . I am looking for
the comparison on why similar code works , while other code not .
I get this
Hi
On 5/14/07, Veer Singh [EMAIL PROTECTED] wrote:
Hello,
I am trying to learn haskell , but i am struggling with types , its
been around 7 days , it will be very kind if some explain it why this
error , i think this is the only stumbling block . I am looking for
the comparison on why similar
Roberto Zunino:
Yes, you are right, I didn't want to involve type classes and assumed
3::Int. A better example would be:
polyf :: Int - a - Int
polyf x y = if x==0 then 0
else if x==1 then polyf (x-1) (\z-z)
else polyf (x-2) ()
Here, passing both () and (\z-z)
Veer,
I get this error on ghci :
{-
`a' is not applied to enough type arguments
Expected kind `*', but `a' has kind `* - *'
In the type `SS a'
In the type `(Monad a) = {Monad (SS a)}'
In the instance declaration for `Monad (SS a)'
-}
So, what you are running into is not as much a
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