Hi!
I've written a hash implementation in pure Haskell. The hash is more of a
collection of elements organized in a table of linked lists, and it can
serve as a dictionary by having each one be a key-value pair.
However, I ran into problems when implementing the show function and hugs
keeps
moved to haskell-cafe
Ketil E.g. way back, I wrote a simple differential equation solver.
Ketil Now, the same function *could* have been applied to vector
Ketil functions, except that I'd have to decide on how to implement
Ketil all the "Num" stuff that really didn't fit well.
Hi everybody:
I think I've found what's the problem. Still no solution in sight :(
The problem has nothing to do with fundeps. Consider an example:
data Foo a = (Eq a) = MkFoo a
This gives the same error message: type variable a is not locally
bound. Apparently, 'a' in 'Eq a' hides 'a' in
On Wed, 7 Feb 2001, Bjorn Lisper wrote:
I'd like to point out the connection between the use of +, - on vector
spaces and * for scaling with features in some data parallel languages. In
these languages, writing a + b where a and b are arrays of numerics is
interpreted as elementwise
My apologies for duplicates of this announcement=
=
= =
=Call For Papers=
=
[moving to haskell-cafe]
From: matt hellige [mailto:[EMAIL PROTECTED]]
a quick question re: ghc's Core language... is it still very similar
to the abstract syntax given in, for example, santos' "compilation by
transformation..." (i think it was his dissertation?) and
elsewhere, or
has it
Marcin 'Qrczak' Kowalczyk:
Me:
I'd like to point out the connection between the use of +, - on vector
spaces and * for scaling with features in some data parallel languages. In
these languages, writing a + b where a and b are arrays of numerics is
interpreted as elementwise addition of a and
As of now, several things have been corrected:
1. Sparc HC files are available.
2. The Windows link actually points to the 4.08.2 release, not the 4.08.1
release.
3. RedHat 6 i386 RPMs are available.
--
http://sc3d.org/rrt/ | computation, n. automated pedantry
Wed, 7 Feb 2001 10:08:14 +0100 (MET), Johannes Waldmann
[EMAIL PROTECTED] pisze:
getLine:: IO String; getLine :: Handle - IO String
At each usage of getLine, the typechecker should follow both tracks,
and take the one that is type-correct.
There is exponential growth of possibilities in
Wed, 7 Feb 2001 13:04:12 +0100 (MET), Bjorn Lisper [EMAIL PROTECTED] pisze:
A natural principle to adopt is that an already typeable expression should
not be transformed. This will for instance resolve the ambiguity in the list
of list example: if l :: [[a]] then length l is already
In thinking about various issues with the numeric classes, I came up
with the following question: Is there a problem with having a class
'Convertible' as follows?
class Convertible a b where
convert :: a - b
So, e.g., fromInteger and fromRational could be replaced with
convert. (But if
Hello!
On Wed, Feb 07, 2001 at 03:43:59PM -0500, Dylan Thurston wrote:
In thinking about various issues with the numeric classes, I came up
with the following question: Is there a problem with having a class
'Convertible' as follows?
class Convertible a b where
convert :: a - b
On Wed, Feb 07, 2001 at 10:19:33PM +0100, Hannah Schroeter wrote:
Hello!
On Wed, Feb 07, 2001 at 03:43:59PM -0500, Dylan Thurston wrote:
In thinking about various issues with the numeric classes, I came up
with the following question: Is there a problem with having a class
Marcin Kowalczyk:
Me:
A natural principle to adopt is that an already typeable expression should
not be transformed. This will for instance resolve the ambiguity in the list
of list example: if l :: [[a]] then length l is already well-typed and
should not be transformed into map length l.
So
On Tue, Feb 06, 2001 at 10:29:36PM +0100, Andreas Gruenbacher wrote:
...
Also not all instances of Num can be shown. I have a monad that is an
instance of Num, for example. I cannot possibly show the monad.
I've been thinking about this a little. It's quite an interesting problem
in general
Hello!
On Wed, Feb 07, 2001 at 05:43:40PM -0500, Dylan Thurston wrote:
[...]
class Subtype a b where {- a is subtype of b, if following operations exist -}
inject :: a - b
project :: b - Maybe a
Shouldn't this be a subclass? 'project' is not always easy or
possible to define.
Dylan Thurston [EMAIL PROTECTED] writes
In thinking about various issues with the numeric classes, I came up
with the following question: Is there a problem with having a class
'Convertible' as follows?
class Convertible a b where
convert :: a - b
[..]
The basic algebra
Wed, 7 Feb 2001 15:43:59 -0500, Dylan Thurston [EMAIL PROTECTED] pisze:
class Convertible a b where
convert :: a - b
So, e.g., fromInteger and fromRational could be replaced with
convert. (But if you did the same thing with toInteger and toRational
as well, you run into problems of
Thu, 8 Feb 2001 00:32:18 +0100 (MET), Bjorn Lisper [EMAIL PROTECTED] pisze:
Two interpretations of a code are "correct", but one is "more correct"
than the other.
It is quite similar in spirit to the concept of principal type in
Hindley-Milner type systems. An expression can have many
Bjorn Lisper [EMAIL PROTECTED] writes:
Two interpretations of a code are "correct", but one is "more correct"
than the other.
It is quite similar in spirit to the concept of principal type in
Hindley-Milner type systems. An expression can have many types but
only one "best" (most general)
Hello
Please help me to solve this questions
Question
Cartesian Product of three sets, written as X x Y x Z is defined as the set
of all ordered triples such that the first element is a member of X, the
second is member of Y, and the thrid member of set Z. write a Haskell
function
Hi,
Im trying to build ghc-4.08.2 on SuSE Linux 7.0 and get the
following error message:
rename/RnEnv.lhs:11:
Bad interface file: rename/RnHiFiles.hi-boot-5
rename/RnHiFiles.hi-boot-5:3 Interface file parse error; on input ` d '
I got the sources by cvs today.
I'm using an
I'm using an existing ghc-4.08.1 installation to compile. I would have
tried to compile with an ghc-4.08.2 compiler build from the x86 HC files,
but the donload link for the HC files doesn't work.
I've fixed the link; sorry about that.
--
http://sc3d.org/rrt/ | RSA, n. safety in numbers
Malcolm Wallace [EMAIL PROTECTED] wrote,
The original haskell.org site seems ok, just mirror.ac.uk is broken.
Oops, retract that. The RedHat 6 packages all seem to be 4.08.1, not
the advertised 4.08.2.
There shouldn't be any links to RedHat 6 packages.
We're providing the links for
Reuben Thomas [EMAIL PROTECTED] wrote,
packages for it. If you have a RedHat 6.x box with an older
version of GHC already installed, just run
rpm --rebuild ghc-4.08.2-1.src.rpm
This will only work if you install RPM 4, no? I couldn't find a way to make
RPM 4 produce v3 RPMs,
Thu, 08 Feb 2001 17:09:19 +1100, Manuel M. T. Chakravarty [EMAIL PROTECTED] pisze:
This will only work if you install RPM 4, no?
True. I didn't know whether the src.rpm format also changed.
AFAIK it did not change.
--
__(" Marcin Kowalczyk * [EMAIL PROTECTED] http://qrczak.ids.net.pl/
moved to haskell-cafe
Ketil E.g. way back, I wrote a simple differential equation solver.
Ketil Now, the same function *could* have been applied to vector
Ketil functions, except that I'd have to decide on how to implement
Ketil all the "Num" stuff that really didn't fit well.
"Ch. A. Herrmann" answers my questions:
Jerzy What do you mean "predefined" operators? Predefined where?
In hugs, ":t (*)" tells you:
(*) :: Num a = a - a - a
which is an intended property of Haskell, I suppose.
Aha. But I would never call this a DEFINITION of this operator.
This
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07 Feb 2001 11:47:11 +0100, Ketil Malde [EMAIL PROTECTED] pisze:
If it is useful to have a fine granularity of classes, you can
imagine doing:
class Multiplicative a b c where
(*) :: a - b - c
Then a*b*c is ambiguous no matter what are types of a,b,c and the
Other people have been making great points for me. (I particularly
liked the example of Dollars as a type with addition but not
multiplication.) One point that has not been made: given a class
setup like
class Additive a where
(+) :: a - a - a
(-) :: a - a - a
negate :: a - a
zero :: a
On Wed, Feb 07, 2001 at 11:47:11AM +0100, Ketil Malde wrote:
"Ch. A. Herrmann" [EMAIL PROTECTED] writes:
[...]
the problem is that the --majority, I suppose?-- of mathematicians
tend to overload operators. They use "*" for matrix-matrix
multiplication as well as for matrix-vector
I have some questions about how Haskell's numeric classes might be
revamped.
Is it possible in Haskell to circumscribe the availability of certain
"unsafe" numeric operations such as div, /, mod? If this is not possible
already, could perhaps a compiler flag "-noUnsafeDivide" could be added
Dylan Thurston writes:
:
| (A question in the above context is whether the literal '0' should
| be interpreted as 'fromInteger (0::Integer)' or as 'zero'.
| Opinions?)
Opinions? Be careful what you wish for. ;-)
In a similar discussion last year, I was making wistful noises about
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