suggestion: add a .ehs file type

Alex Jacobson alex at
Wed Nov 21 13:38:35 EST 2007

Isn't use of the extensions detectable by the compiler?

If so, then forcing the user manually to enumerate them at the top of a 
source file seems like forcing the user to write a lot of unnecessary 
boilerplate.  It seems preferable for the compiler ny default just to 
issue warnings about what extensions are used.  Then the person doing 
the compiling can decide to modify code not to use those features, to 
add pragmas so as not to cause warning, or to add compiler flags that 
tells it not to issue them.

In any case, I'm pretty sure the correct answer is not 50 language 
pragmas with arbitrary spellings for various language features at the 
top of each source file.


Simon Marlow wrote:
> Alex Jacobson wrote:
>> I'm fine with that as well.  I'm just opposed to being force to look 
>> up the precise names the compiler happens to use for each language 
>> extension I happen to use.  Having -fglasgow-exts turned on by default 
>> also works.
> -fglasgow-exts is a historical relic.  It's just an arbitrary collection 
> of extensions.  It doesn't contain all the extensions provided by GHC, 
> as many of them steal syntax and you probably don't want them all on at 
> the same time.  We're trying to move away from -fglasgow-exts, which is 
> why GHC 6.8.1 provides separate flags for all the extensions we provide. 
> Eventually we'll have a new standard (Haskell' or whatever) that will 
> collect many of the extensions together, so you'll just have to write 
> {-# LANGUAGE Haskell' #-}.
> Cheers,
>     Simon
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