| The code is hand-written and the maximum tuple-size
| used is 4. It works fine in Hugs. It uses the Parsec
| library (not the version in GHC's text package, but
| from a local copy. The ParsecPrim.hs was replaced by
| the version from Parsec's web-site -- it works as I
| expected, but not the
The real question is:
why does GHC distinguish kind * from kind #?
For example, Int has kind *
Int# has kind #
The main reason is this: a polymorphic function assumes that values of
type 'a' are represented by a pointer. For example:
const :: a - b - a
const
I've implemented timeouts as described in:
http://www.haskell.org/pipermail/glasgow-haskell-users/2001-April/001816
.html
My implementation follows:
timeout secs onTimeout action = do
parent - myThreadId
i - newUnique
block $ do
timeoutT - forkIO (timeoutThread secs parent i)
On Mon, 4 Aug 2003, Ashley Yakeley wrote:
At 2003-08-04 20:00, Ben Rudiak-Gould wrote:
This is a different lambda calculus, with a different beta rule. You can
see the same effect in the type inference rules for implicit parameters:
If f has type Int - String and ?x has type (?x :: Int) =
I just figured out why the monomorphism restriction interacts so weirdly
with implicit parameters, and how to fix it.
We all know that when the monomorphism restriction is turned on, the
following doesn't work:
let f = () in (f 1 2, f 'a' 'b')
On the other hand, the following does work:
At 2003-08-04 18:19, Ben Rudiak-Gould wrote:
((\a - ((a,[EMAIL PROTECTED] - @x) [EMAIL PROTECTED] = 2})) ([EMAIL PROTECTED] -
@x),[EMAIL PROTECTED] - @x) [EMAIL PROTECTED] = 1}
^^^
(([EMAIL PROTECTED] - @x,[EMAIL PROTECTED] - @x) [EMAIL PROTECTED] =
This message illustrates how safe casting with multiple universes can
be extended to new user-defined, polymorphic datatypes. We show a
_portable_ mapping of polymorphic types to integers. Different
instances of a polymorphic type map to different integers. Phantom
types can be either disregarded
Immanuel Litzroth [EMAIL PROTECTED] writes:
I have a small question relating to literate haskell programs that
use the \begin{code} \end{code} style. Am I correct to assume that
\end{code} inside a string should be recognized as being inside a
string. The report seems to say this, but the
| I just figured out why the monomorphism restriction interacts so
weirdly
| with implicit parameters, and how to fix it.
I'm afraid that I have not read all of the recent exciting flood of
messages carefully, but I do remember that the interaction of the
monomorphism restriction with implicit
I have a small question relating to literate haskell programs that
use the \begin{code} \end{code} style. Am I correct to assume that
\end{code} inside a string should be recognized as being inside a
string. The report seems to say this, but the unlit that is
distributed with ghc doesn't grok
On Mon, 4 Aug 2003, Ashley Yakeley wrote:
At 2003-08-04 22:33, Ben Rudiak-Gould wrote:
This illustrates what you pointed out earlier, that the
program's semantics can be changed by adding explicit type signatures
which include implicitly-parameterized parameters.
But wasn't avoiding this
this is true; however, it is likely that it would be much faster for me
to read in word8s and parse them to Ints myself than to read in Chars
(using the old libraries) and parse those to ints (I've done some
experiments and the overhead for reading haskell Chars is very
non-negligible). i'd like
On Tue, 5 Aug 2003 12:23:06 +0200
Konrad Hinsen [EMAIL PROTECTED] wrote:
3
Is there any way to parametrize a type by a value, rather than
another type? What I would like to do is to define list of length 3
and list of length 4 as separate parametrization of the same type,
such that I
A better solution might be:
data EmptyList element = EmptyList
data TrueList list element = TrueList element (list element)
A list of four Ints for example would be represented by a value of type
TrueList (TrueList (TrueList (TrueList EmptyList))) Int.
Isn't that just the
Is there any way to parametrize a type by a value, rather than another
type?
I believe the following web page answers your question:
http://pobox.com/~oleg/ftp/Haskell/number-parameterized-types.html
It uses parameterization by decimal numbers -- which seem more
natural to read.
On Tue, 5 Aug 2003 15:23:09 +0200
Wolfgang Jeltsch [EMAIL PROTECTED] wrote:
You could define different types for different natural numbers:
data Zero = Zero
data Succ number = Succ number
This resembles
http://www.brics.dk/RS/01/10/
V.
16 matches
Mail list logo
