[Haskell-cafe] Re: check if program uses haskell 98 only?

Henning Thielemann lemming at henning-thielemann.de
Thu Jan 3 06:06:11 EST 2008

On Thu, 6 Dec 2007, Henning Thielemann wrote:

> On Thu, 6 Dec 2007, Thomas Hartman wrote:
> > On a related note... is there some easy way to be sure that a program I am
> > compiling uses only haskell 98? (Because any pure haskell 98 should always
> > compile on yhc... right?)
> You can for instance use 'haskell98' as dependent package instead of
> 'base' in the Cabal description. If you import other modules, I don't know
> how to check that these are Haskell 98. I weakly remember corner cases
> where GHC accepts more than Haskell 98 in Haskell 98 mode. (At least it
> sometimes suggests fixes for errors that are not Haskell 98, e.g.  class
> constraints in signatures. :-)

Now I have an example: GHC-6.4.1 accepts multi parameter type class
constraints without '-fglasgow-exts'.

> > I compile this with ghc, no options, and iIt doesn't have any {-#-#}
> > options, so according to what I understand, it is using pure haskell 98.
> > So I might think this was a candidate for using on yhc.
> I could not always pass a GHC-certified module to Hugs or even Haddock. I
> remember there is some difference with respect to the trailing 'where' in
> the 'instance' head, if the instance declaration is empty.  Haddock expect
> some spaces in infix operators (I believe ( # ) instead of (#)), which are
> not required by Hugs and GHC.

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