Happy Question

[Ashley Yakeley]

My hand-written S-expression parser for HScheme is very very slow. 
Really quite a bit slower than it ought to be. So I'd like to switch to 
Happy instead.

The problem is my parser should be monadic, but the monad type is 
generalised (basically of the form (context m) => m). Is there a way of 
switching on monadic-ness, so I can have a monadic happyError, but 
without giving type signatures to happyThen and happyReturn? Or else 
allowing a class context for the type signatures?

-- 
Ashley Yakeley, Seattle WA