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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?

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bjwbell
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  • exact duplicate http://stackoverflow.com/questions/993112/what-does-the-exclamation-mark-mean-in-a-haskell-declaration – Lombo Apr 13 '10 at 19:27

1 Answers1

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

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