On Aug 23, 2012, at 10:32 PM, wren ng thornton wrote:
Now, be careful of something here. The reason this fails is because we're
compiling Haskell to System Fc, which is a Church-style lambda calculus
(i.e., it explicitly incorporates types into the term language). It is this
fact of being
While working on a project I have come across a new-to-me corner case of the
type system that I don't think I understand, and I am hoping that someone here
can enlighten me.
Here's a minimal setup. Let's say I have some existing code like this:
{-# LANGUAGE Rank2Types #-}
class
On Aug 22, 2012, at 3:02 PM, Lauri Alanko wrote:
Quoting Matthew Steele mdste...@alum.mit.edu:
{-# LANGUAGE Rank2Types #-}
class FooClass a where ...
foo :: (forall a. (FooClass a) = a - Int) - Bool
foo fn = ...
newtype IntFn a = IntFn (a - Int)
bar :: (forall
On Aug 22, 2012, at 4:32 PM, Erik Hesselink wrote:
On Wed, Aug 22, 2012 at 10:13 PM, Matthew Steele mdste...@alum.mit.edu
wrote:
On Aug 22, 2012, at 3:02 PM, Lauri Alanko wrote:
Quoting Matthew Steele mdste...@alum.mit.edu:
{-# LANGUAGE Rank2Types #-}
class FooClass a where
Doesn't for already exist, in Data.Traversable? Except that for =
flip traverse.
http://www.haskell.org/hoogle/?hoogle=for
Cheers,
-Matthew
On Wed, Mar 28, 2012 at 3:58 PM, Johannes Waldmann
waldm...@imn.htwk-leipzig.de wrote:
Good: we have mapM, and we have forM ( = flip mapM ) .
Sure
On Mar 28, 2012, at 4:19 PM, Christopher Done wrote:
On 28 March 2012 22:05, Matthew Steele mdste...@alum.mit.edu wrote:
Doesn't for already exist, in Data.Traversable? Except that for =
flip traverse.
Traverse doesn't fit the type of fmap, it demands an extra type
constructor
On Jun 21, 2011, at 4:02 PM, Malcolm Wallace wrote:
On 21 Jun 2011, at 20:53, Elliot Stern wrote:
A tuple is basically an anonymous product type. It's convenient to
not have to spend the time making a named product type, because
product types are so obviously useful.
Is there any reason
On Mon, Jun 6, 2011 at 3:39 PM, Casey McCann syntaxgli...@gmail.com wrote:
On Mon, Jun 6, 2011 at 12:19 PM, Brent Yorgey byor...@seas.upenn.edu wrote:
The idea is that Applicative computations
have a fixed structure which is independent of intermediate results;
Monad computations correspond to
From Haskell, I want to call a C function that returns a struct by
value (rather than, say, returning a pointer). For example:
typedef struct { double x; double y; } point_t;
point_t polar(double theta);
I can create a Haskell type Point and make it an instance of Storable
easily
In my own code, I usually use a 'mb' prefix with camelCase, like so:
case mbStr of
Just str - ...
Nothing - ...
But I agree that it doesn't always look very nice. I'm curious what
others do.
On Apr 22, 2011, at 1:14 PM, Evan Laforge wrote:
Here's a simple issue that's been with
On Mar 30, 2011, at 5:29 PM, Mathijs Kwik wrote:
So loop really doesn't seem to help here, but I couldn't find another
way either to feed outputs back into the system.
What I need is:
Either A B ~ Either C B - A ~ C
Does such a thing exist?
Based on your description, it sounds to me like you
Sounds like you're looking for `last', which is in the Prelude.
http://www.haskell.org/ghc/docs/6.12.2/html/libraries/base-4.2.0.1/Prelude.html#v%3Alast
Cheers,
-Matt
On Dec 31, 2010, at 3:39 PM, Aaron Gray wrote:
Is there an easy Haskell function that gets the last Char of a
[Char] or
TAPL is also a great book for getting up to speed on type theory:
http://www.cis.upenn.edu/~bcpierce/tapl/
I am no type theorist, and I nonetheless found it very approachable.
I've never read TTFP; I will have to check that out. (-:
On Nov 19, 2010, at 4:31 PM, Daniel Peebles wrote:
I have an object to which I have added one or more finalizers via
addFinalizer from System.Mem.Weak. I would like to have a function
that allows me to make use of the object within a block of IO code,
and guarantee that the finalizer(s) will not be called during the code
block -- sort of
14 matches
Mail list logo
