Bang patterns

Simon Peyton-Jones simonpj at
Mon Feb 6 06:09:11 EST 2006

Earlier on the Haskell' list, I proposed bang patterns as a way to make
it more convenient for Haskell programmers to make their programs
stricter.  E.g.
	f (!x, y) = ....

I've documented the proposal here

I've implemented it in GHC, so you can try it out.  Use
to enable bang patterns.   If you use -fglasgow-exts you get
-fbang-patterns as well.  If you don't want that, use -fglasgow-exts

I'd be interested to hear your experiences.  (Committee members: do add
notes to the Wiki page giving pros and cons.)


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