Variables in Haskell

Question

Why does the following Haskell script not work as expected?

find :: Eq a => a -> [(a,b)] -> [b]
find k t = [v | (k,v) <- t]

Giv

Answer 1

You can only pattern match on literals and constructors.
You can't match on variables. Read more here.

That being said, you may be interested in view patterns.