Hi folks
I'm having a play with Concurrent Haskell, and came across this in the
library.
readMVar :: MVar a -> IO a
This is a combination of takeMVar and putMVar; ie. it takes the value
from the MVar, puts it back, and also returns it.
I was just wondering if I understand things correctly. Su
at a guess the magic take put is:
block ( do
a <- takeMVar x
putMVar x a
)
return a
Keean.
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> -- gaSolutionSpace :: [a] -> [a]
> -- gaSolutionSpace [] = gaSolutionSpace createRandomPopulation -- recursive
> base case
> gaSolutionSpace x = x : gaSolutionSpace (evolvepopulation x)
This isn't quite right - you don't want the *last* element to be the initial
population, but the first.
I t
On 02 July 2004 10:16, Conor T McBride wrote:
> Hi folks
>
> I'm having a play with Concurrent Haskell, and came across this in the
> library.
>
>readMVar :: MVar a -> IO a
>This is a combination of takeMVar and putMVar; ie. it takes the
>value from the MVar, puts it back, and also r
On Jun 29, 2004, at 6:46 PM, Iavor S. Diatchki wrote:
In Haskell, natural transformations are polymorphic functions, tau
:: f a -> g a. For example, maybeToList :: Maybe a -> [a].
actually i think this is a good approximation. not all polymorphic
functions are natural transformations, but "simp
I am trying to model state in the continuation monad,
such that each continuation recieves the current state
as one of its arguments. The state must vary in type,
which is why I am trying to use the continuation monad,
but things don't seem to be going too well.
To clarify... imagine the following
> at a guess the magic take put is:
>
> block ( do
> a <- takeMVar x
> putMVar x a
> )
> return a
This doesn't prevent the race condition Conor mentioned. It only prevents
the thread executing the above code from being interrupted by an
asynchronous exception (i.e., Control-C, or another thread
{-# OPTIONS -fglasgow-exts #-}
{-
Regarding Keean's posting ...
I wonder whether perhaps a more basic step is to understand
how type-changing monadic computations can be understood.
By this I mean, that the effects model by the monad can change
their type as part of the computation. Such a monad
Conor T McBride wrote:
... [questions about operation ordering with MVars]
>
I'm only asking, because I'm trying to cook up some kind of partial
evaluator for programs which are being simultaneously edited by
fiercely argumentative devils. Kind of `demonic laziness', where
the computations decide w
hello,
i was thinking of higher-order functions, which i think complicate things
(i might be wrong though :-)
for example:
fix :: (a -> a) -> a
is ploymorphic, but is it a natural tranformation?
i belive it is in fact a di-natural transformation.
-iavor
On Jun 29, 2004, at 6:46 PM, Iavor S. Diatchk
The idea of using a general purpose programming language for making music
as provided by Haskore is very attractive to me. Especially Haskell seems
to be a good choice for this task, since the lazy evaluation in principle
allows an immediate play back without the necessity to build the complete
so
Crypt Master writes:
>From what I can see, a key difficulty you're having is with the
"evolvepopulation" function. You've given it the type a -> a, which
pretty much requires it to be an identity function, because it's not
allowed to make any assumptions about the values it takes.
To make things
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