Hello Brian,
Tuesday, June 13, 2006, 1:11:37 AM, you wrote:
data UTF8Stream h = (ByteStream h) = UTF8Stream h
instance TextStream (UTF8Stream h) ...
addUTF8Encoding :: h - (UTF8Stream h)
and so on. currently i should add type constraint to each and every
class and function i declared.
you need at least one constructor if you say 'where'.
S
| -Original Message-
| From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Brock
| Peabody
| Sent: 09 June 2006 20:34
| To: haskell-cafe@haskell.org
| Subject: RE: [Haskell-cafe] newbie type signature question
Bulat Ziganshin wrote:
Hello Brian,
Saturday, June 10, 2006, 3:05:25 AM, you wrote:
It is possible that this feature was added to the language for the
benefit of people who prefer not to use explicit type signatures but
afaiu this goes against best practice where everything should always
have
Hello Brian,
Saturday, June 10, 2006, 3:05:25 AM, you wrote:
It is possible that this feature was added to the language for the benefit
of people who prefer not to use explicit type signatures but afaiu this goes
against best practice where everything should always have an explicit
On 6/9/06, Brandon Moore [EMAIL PROTECTED] wrote:
data DataType m = forall m' . (Monad m') = DataType (TyEq m m') (Char
- m' ())
It appears that the more intuitive formulation:
data DataType m
where DataType :: Monad m = (Char - m ()) - DataType m
should work in GHC 6.4
/g
Brian Hulley wrote:
Don't put class constraints on a data type,
constraints belong only to the functions
that manipulate the data.
So according to this guideline you're not supposed to think of
associating
contraints with data: constraints are only relevant for functions
which
From: Bulat Ziganshin [mailto:[EMAIL PROTECTED]
when you work with C++ or some other OOP language, you can define that
some field in structure should some some specific interface and this
allows to use functions of this interface on this field. i required
the same feature in Haskell, for
Please excuse my newbiness, but in this snippet:
data (Monad m) = DataType m = DataType { f :: Char - m () }
test_function :: (Monad m) = DataType m - m ()
test_function d = f d 'C'
Why is (Monad m) = required, when the definition
Brock Peabody wrote:
Please excuse my newbiness, but in this snippet:
data (Monad m) = DataType m = DataType { f :: Char - m () }
test_function :: (Monad m) = DataType m - m ()
test_function d = f d 'C'
Why is (Monad m) = required, when the definition
Brian Hulley wrote:
There was a post a while back (unfortunately I can't seem to locate
it)
where someone posted a link to some guidelines on haskell coding style
where
one guideline was never to use contexts in data declarations.
I would love to see that guideline. What is the correct way
From: Brandon Moore
Getting them both is tricky, but you can do it if you use a GADT to
write a type that means exists a such that a = m and a is a Monad:
Is GADT a way to assemble types at compile-time? It looks really cool.
{-# OPTIONS -fglasgow-exts #-}
data TyEq (a :: * - *) (b :: * -
Sorry, I meant to send this to the whole list.
Brock Peabody wrote:
Please excuse my newbiness, but in this snippet:
data (Monad m) = DataType m = DataType { f :: Char - m () }
test_function :: (Monad m) = DataType m - m ()
Hello Brian,
Friday, June 9, 2006, 9:50:30 PM, you wrote:
data (Monad m) = DataType m = DataType { f :: Char - m () }
test_function :: (Monad m) = DataType m - m ()
There was a post a while back (unfortunately I can't seem to locate it)
where someone
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