Colin Paul Adams wrote:
I'm getting these errors (ghc 6.10.4 on Linux x86_64):
Building chp-plus-1.1.0...
[1 of 9] Compiling Control.Concurrent.CHP.Test (
Control/Concurrent/CHP/Test.hs, dist/build/Control/Concurrent/CHP/Test.o )
[2 of 9] Compiling Control.Concurrent.CHP.Console (
Control/Concurrent/CHP/Console.hs, dist/build/Control/Concurrent/CHP/Console.o )
[3 of 9] Compiling Control.Concurrent.CHP.Connect (
Control/Concurrent/CHP/Connect.hs, dist/build/Control/Concurrent/CHP/Connect.o )
Control/Concurrent/CHP/Connect.hs:146:67:
Couldn't match expected type `ChanOpts a'
against inferred type `ConnectableParam (Chanout a)'
In the first argument of `oneToOneChannel'', namely `o'
In the second argument of `(<$>)', namely `oneToOneChannel' o'
In the first argument of `(>>=)', namely
`((writer &&& reader) <$> oneToOneChannel' o)'
I don't immediately have a GHC 6.10.4 machine to hand, but that is an
odd error. Here is the code in question:
instance ConnectableExtra (Chanout a) (Chanin a) where
type ConnectableParam (Chanout a) = ChanOpts a
connectExtra o = (>>=) ((writer &&& reader) <$> oneToOneChannel' o)
(based on the class:
class ConnectableExtra l r where
type ConnectableParam l
connectExtra :: ConnectableParam l -> ((l, r) -> CHP ()) -> CHP ()
)
So I don't see why there is a type mismatch; ConnectableParam (Chanout
a) is ChanOpts a. I don't know if it's somehow confused by the recently
added similar instance:
instance ConnectableExtra (Chanout a) (Shared Chanin a) where
type ConnectableParam (Chanout a) = ChanOpts a
connectExtra o = (>>=) ((writer &&& reader) <$> oneToAnyChannel' o)
There's no conflict between the two instances, though. I wonder if
making ConnectableParam depend on "l" and "r" would fix it. I'll look
further into this when I get onto a 6.10.4 machine.
Thanks,
Neil.
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