On Thu, Dec 18, 2008 at 2:00 AM, Nicolas Pouillard
<[email protected]> wrote:
> I don't see why one would need session types, channels... to express that.
> I maybe need a more complicated coroutines (ruby) example that would require
> using this system.
OK, how would you type these routines in Haskell?
def simple
yield "hello"
yield 1
yield (lambda { |x| x + 1 })
end
def useSimple
state = 0
result = nil
simple { |x|
if (state == 0) then result = x
else if (state == 1) then result += (x * 4).toString
else if (state == 2) then result += x.call(10).toString
state = state + 1
}
result
end
I know it's a bit contrived, but you get the idea.
In Haskell using Control.Coroutine:
simple :: forall rest. Session (String :!: Int :!: (Int -> Int) :!:
rest) rest ()
simple = do
put "hello"
put 1
put (\x -> x + 1)
useSimple :: forall rest. Session (String :?: Int :?: (Int -> Int) :?:
rest) rest String
useSimple = do
string <- get
int <- get
func <- get
return (string ++ show (int * 4) ++ show (func 10))
result :: String
result = snd $ connects simple useSimple
-- result = "hello411"
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