"Eray Ozkural (exa)" wrote:
>
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> Let me offer a differing view of Monads.
>
> Monads are a way to write type-safe imperative programs within a functional
> framework. It's just an advanced version of PROGN kludge in LISP.
>
> Since they are ba
A while ago, to help myself understand newtype, data, and strictness,
I tried to write down how Haskell types correspond to lifted domains.
Here is a cleaned-up version of my attempt. I am not sure that what
follows is entirely correct -- please point out any errors. I would
also appreciate comm
Hi,
> data T -- has 1 value: _|_
Minor nitpick: that Hugs and GHCi accept it, doesn't mean it's legal
Haskell'98. Otherwise we would have existential and universal quantified
types as well :-)
Cheers,
Jan
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Tue, 15 Jan 2002 13:06:58 +0100, Rijk-Jan van Haaften <[EMAIL PROTECTED]> pisze:
> This feature is one I consider among the worst in Haskell. If
> a datatype with just a single constructor can be optimized away,
It can't. newtype has a different semantics than data, as others
explained. It would
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Let me offer a differing view of Monads.
Monads are a way to write type-safe imperative programs within a functional
framework. It's just an advanced version of PROGN kludge in LISP.
Since they are based on a linear flow of "commands", they seem to
hello,
it looks like a lot of Haskell experts are at POPL (prog. language conference)
and are not checking their email... so here is my attempt at explaining the
differences between data and newtype.
data T -- has 1 vale: _|_
data T = T -- has 2 values: _|_, T
data T = T (
> I see a lot of literature that says that monads "simulate" the effects of
> imperative programming concepts.
I think that's just bad wording. To take a rather trite
point of view, in a language such as C /everything/ is done
within a monad, and all types, even int, are really IO
something (IO
Eric Allen Wohlstadter <[EMAIL PROTECTED]> wrote,
>> non-local transfer of control. Similiar is the way State is handled. Do
>> compilers for haskell do any sort of optimization on these monadic
>> operations or is it all as ineffecient as it looks.
On Wed, Jan 16, 2002 at 08:59:14PM +1100, Manue
Eric Allen Wohlstadter <[EMAIL PROTECTED]> wrote,
> I see a lot of literature that says that monads "simulate" the effects of
> imperative programming concepts. It seems to me that the relative
> performance of monadic implementations must be equivalant to imperative
> ones to provide a strong ca
No-one appears to have responded to this with a definitive answer...
On Tue, 15 Jan 2002, Feuer wrote:
> I know what you mean. However, if you look at it,
> data Empty1 a = E1
> is a datatype with one constructor, and that constructor takes no arguments.
> So this is in fact a "phantom" unit ty
I see a lot of literature that says that monads "simulate" the effects of
imperative programming concepts. It seems to me that the relative
performance of monadic implementations must be equivalant to imperative
ones to provide a strong case for functional programming. For example, in
the Exceptio
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