Hello everyone,
I've been banging my head against my desk a bit so I figured it's time
to ask for help :-)
I'm writing an application that persists data to disk. The hard stuff
is pretty much done (binary serialisation, etc...) The big stumbling
block is that I want users to be able to
Hi All,
One important property of type class dictionary translation is coherence
which basically says that two typing derivations for the same term at the
same type in the same environment must be equivalent. This definition is
established with the assumption of non-overlapping.
In the GHC
I'm interested, but I don't have the time to look right now (or in the next
couple of months, as far as I can see).
What would really interest me is a system that can provide the functionality of
the Python packages I currently use (TurboGears [1], of which the web
server/controller component is
On 4/12/06, Scott Weeks [EMAIL PROTECTED] wrote:
Hello everyone,
I've been banging my head against my desk a bit so I figured it's time
to ask for help :-)
When a user queries I have to read the input from IO and then somehow
cast the key/index type without angering the type checker. If I
On Apr 11, 2006, at 10:09 AM, David F. Place wrote:
Hi All,
Since it seems that real applications need more than just union,
intersection, difference and complement to be fast to make EnumSet
useful, I've been looking into the less naive approaches to the
other things. In particular,
| In the GHC documentation which describes the extension of overlapping
| instances, an example similar to the following is given.
|
| class C a where
|f:a - a
| instance C Int where
|f=e1
| instance C a where
|f=e2
|
| let g x = f x
| in g 1
|
| In this case GHC takes an
Well, if you get an ambiguous type variable error, you probably (I
think) need to add some type annotations. For example:
class Foo a where
foo :: a
bar :: a - String
Evaluating bar foo will result in an error, but bar (foo :: Integer)
will work just fine.
The
On Apr 12, 2006, at 3:18 PM, Scott Weeks wrote:
Well, if you get an ambiguous type variable error, you probably (I
think) need to add some type annotations. For example:
class Foo a where
foo :: a
bar :: a - String
Evaluating bar foo will result in an error, but bar (foo :: Integer)
On Wednesday 12 April 2006 02:09, David F. Place wrote:
If you'd like to give it a whirl on your fancy modern computers,
Averages of user time for three runs on an Athlon64 running 64bit linux:
kern0.29700
ones32 0.30733
table32 0.37333
table 0.38400
I ran a whole lot more of kern and
Robert Dockins wrote:
On Apr 12, 2006, at 3:18 PM, Scott Weeks wrote:
Well, if you get an ambiguous type variable error, you probably (I
think) need to add some type annotations. For example:
class Foo a where
foo :: a
bar :: a - String
Evaluating bar foo will result in an error,
Or carry an instance in along with a type parameter, using
existentials or GADT.
Brandon Moore
Do you know of an example that would apply to my situation?
I think I neglected to state part of my problem. I am storing the root
nodes of btree indexes in a heterogeneous list using Typeable.
On Apr 12, 2006, at 3:30 PM, Daniel McAllansmith wrote:
Averages of user time for three runs on an Athlon64 running 64bit
linux:
kern0.29700
ones32 0.30733
table32 0.37333
table 0.38400
I ran a whole lot more of kern and ones32... kern was consistently
faster than
ones32.
On Apr 12, 2006, at 4:09 PM, Scott Weeks wrote:
Or carry an instance in along with a type parameter, using
existentials or GADT.
Brandon Moore
Do you know of an example that would apply to my situation?
I think I neglected to state part of my problem. I am storing the
root nodes of
On Thursday 13 April 2006 08:55, David F. Place wrote:
On Apr 12, 2006, at 3:30 PM, Daniel McAllansmith wrote:
Averages of user time for three runs on an Athlon64 running 64bit
linux:
kern0.29700
ones32 0.30733
table32 0.37333
table 0.38400
I ran a whole
On Apr 12, 2006, at 5:21 PM, Daniel McAllansmith wrote:
Averages of user time of five runs on an Athlon64 running 64bit linux:
64 0.1974
kern0.2980
ones32 0.3240
table32 0.3754
table 0.3798
64 looks to be a good bit faster.
You didn't change anything in the ones32 algorithm did
You are trying to assign two distinct types to dynFoo; that's a no-no.
You need to move the usage of the polymorphic function out of the let
so that the use at each distinct type doesn't get unified.
{-# OPTIONS -fglasgow-exts #-}
import Data.Dynamic
data Foo a = FVal a
On Wednesday 12 April 2006 22:52, Graham Klyne wrote:
I'm interested, but I don't have the time to look right now (or in the next
couple of months, as far as I can see).
What would really interest me is a system that can provide the
functionality of the Python packages I currently use
Halfs is a filesystem implemented in the functional programming
language Haskell. Halfs can be mounted and used like any other Linux
filesystem, or used as a library. Halfs is a fork (and a port) of the
filesystem developed by Galois Connections.
We've created a virtual machine to make using
Hi,
So I'm trying the fun-deps example from
http://www.haskell.org/hawiki/FunDeps and seeing if I can
use it, but I can't really get things to work the way I want.
The code follows below, and the error I get if I try to multiply
10 * (vector 10 [0..9]) is
No instance for (MatrixProduct a (Vec
Thank you Simon.
But I am still confused by the exact definition of coherence in the case of
overlapping. Does the standard coherence theorem apply? If yes, how? If no,
is there a theorem?
Is there any write-up on this?
Thanks.
--william
From: Simon Peyton-Jones [EMAIL PROTECTED]
To:
Creighton Hogg wrote:
No instance for (MatrixProduct a (Vec b) c)
arising from use of `*' at interactive:1:3-5
Probable fix: add an instance declaration for (MatrixProduct a
(Vec b) c)
In the definition of `it': it = 10 * (vector 10 ([0 .. 9]))
Let us look at the
But I am still confused by the exact definition of coherence in the case of
overlapping. Does the standard coherence theorem apply? If yes, how?
If no, is there a theorem?
Yes, the is, by Martin Sulzmann et al, the Theory of overloading (the
journal version)
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