[Haskell-cafe] function terms

[Henning Thielemann]

On Wed, 6 Jul 2011, Ian Childs wrote:

> Suppose I have two terms s and t of type "a" and "b" respectively, and I want 
> to write a function that returns s applied to t if "a" is an arrow type of 
> form "b -> c", and nothing otherwise. How do i convince the compiler to 
> accept the functional application only in the correct instance?

Why can't 's' simply have type 'b -> c'? With "term" do you mean a Haskell 
expression?