suggestion: add a .ehs file type

Alex Jacobson alex at
Wed Nov 21 19:26:10 EST 2007

Ok, I'm game to default to haskell98 in the presence of ambiguity, but 
in most cases the extension involves new syntax and that should be enough.

Note: I would also argue that extensions that change the meaning of old 
code are prime-facie a bad idea.  It means that, if you start using the 
new syntax in your existing code, you have manually to audit your code 
to make sure nothing else got broken and that is difficult even for 
experts to do really well.  The example you provide is actually evidence 
that this bang-pattern extension is probably a bad one.


Duncan Coutts wrote:
> On Wed, 2007-11-21 at 15:03 -0500, Alex Jacobson wrote:
>> Proof that the compiler knows which extensions are being used: it can 
>> compile the program sucessfully when the extension is turned on and not 
>> otherwise.
> Counterexample (not my own):
> {-# OPTIONS_GHC -fbang-patterns #-}
> foo _ = "lol"
> main = putStrLn (foo "wut")
>     where
>     foo !x = x
> Duncan

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