[Haskell-cafe] Re: Type-level lambdas in Haskell? ( was Multiparameter class error)

On 2/22/07, oleg@pobox.com wrote:

First of all, the design already exhibits the problem:

[snip]

The reason is that [..] the function delaySY is declared *fully* polymorphic over 'a' -- there are no constraints on a and no restrictions. However,

...

delaySY :: HDPrimType a => a -> HDSignal a -> HDSignal a

I didn't even notice this problem.

I'm not certain if there is a compelling reason to place mapSY, delaySY and zipWithSY in the same class

There's not such a reason, I was just stupid enough to overlook that splitting the class would do the trick.

If not, the following is the solution to the problem.

Certainly :) Even if your solution doesn't look really elegant, it's the perfect workaround ... as it's the only one I have. Thanks a lot.