Usage of ! in a Haskell type

Question

Possible Duplicate:
What does the exclamation mark mean in a Haskell declaration?

In Alex the generated boilerplate code includes

data AlexPosn = AlexPn !Int  -- absolute character offset
                       !Int  -- line number
                       !Int  -- column number

What does the ! in front of the Int indicate?

Answer 1

It´s a strictness flag as oposed to lazy evaluation.