Re: suggestion: add a .ehs file type

12 Dec 2007


      Alex, Lennart's suggestion makes me think: Why not make SearchPath
into a preprocessor?  It could recognize a .ehs extension, and then do
some very simple preprocessing (adds pragmas according to user's
settings).

-- 
Robin Bate Boerop

On 22/11/2007, Lennart Augustsson  wrote:
...
Or use a preprocessor that inserts a LANGUAGE pragma. :)
On Nov 22, 2007 9:14 AM, Simon Marlow  wrote:
...
Alex Jacobson wrote:
...
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.
You probably won't like any of these, but there are many ways to avoid
writing out all the pragmas at the top of each file.
1. Use Cabal's extensions field.
2. Use CPP
MyExtensions.h :
{-# LANGUAGE TemplateHaskell, FlexibleInstances,
             OverlappingInstances, UndecidableInstances, CPP,
             ScopedTypeVariables, PatternSignatures, GADTs,
             PolymorphicComponents, FlexibleContexts,
             MultiParamTypeClasses, DeriveDataTypeable,
             PatternGuards #-}
MyModule.hs:
{-# LANGUAGE CPP #-}
#include "MyExtensions.h"
3. Use a shell alias
alias ghce='ghc -XTemplateHaskell -XFlexibleInstances ...'
4. use a script wrapper for GHC
#!/bin/sh
exec ghc -XTemplateHaskell -XFlexibleInstances ... $*
I'm sure there are more...
Cheers,
       Simon
...
-Alex-
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