[Haskell] -compiler-options vs {#-LANGUAGE Flags-#}

[John Meacham]

On Thu, Apr 05, 2007 at 10:53:31AM -0700, Stefan O'Rear wrote:
> On Thu, Apr 05, 2007 at 10:42:09AM -0700, John Meacham wrote:
> > On Sat, Mar 24, 2007 at 01:18:30PM +0100, Lennart Kolmodin wrote:
> > > I think the LANGUAGE pragma is much better than OPTIONS_GHC, for several
> > > reasons.
> > > 
> > > * It's compiler independent.
> > > * It's clear that you're only adding extensions, not any random compiler
> > > flag.
> > > * It plays nicely with Ian's proposal on
> > > http://article.gmane.org/gmane.comp.lang.haskell.cabal.devel/464
> > 
> > A very big problem with the pragma as it relates to
> > Distribution.Extension is that it is unextensable. The definition in
> > Distribution.Extension really should be 
> > 
> > > newtype Extension = Extension String
> > 
> > and the flags transformation should be something like
> > 
> > > extensionsToFlags :: Compiler -> [Extension] -> ([Extension],[Opt])
> > > extensionsToFlags = ...
> > 
> > enumerating the compilers or allowed extensions in the API is very
> > limiting as well as complicating to the code.
> > 
> > This is a major problem with Distribution.* in general actually that
> > needs to be cleaned up at some point. (Distribution2.* ?) hrm..
> 
> It would be a Very Good Idea to list the "valid" values in the
> haddocks, to ensure consistency.  We can handle assignment with a
> "Find a missing extension?  Invent a name and patch this list!"
> clause. 

oh, yes of course. I was thinking a wiki page could list valid ones and
pointers to the papers/documentation describing them.

and of course, we can reserve X-Foo named extensions for as yet to be
standardized or experimental extensions so developers have a playground
to work in as extensions evolve.

        John

-- 
John Meacham - ⑆repetae.net⑆john⑈