A pre-processor is a great idea. Template Haskell and Cabal make it possible to extend the language by adding all kinds of funky pre-processing (via Cabal hooks) and compile-time calculations. It wouldn't be too difficult to add a package-specific .ehs file type with the desired behavior. I'm currently using this combo to work around the TH limitation of not being able to generate import statements. A Cabal hook looks in a directory to find what .hs files are present, spits out an intermediate file that imports all of these files, and Cabal compiles the generated file into the final program. I think that the biggest limitation of this setup is managing the files if multiple stages of pre-processing are performed. Richard -------- Original Message -------- Subject: Re: suggestion: add a .ehs file type Date: Thu, 22 Nov 2007 10:19:57 +0000 From: Lennart Augustsson <lennart@augustsson.net> To: Simon Marlow <simonmarhaskell@gmail.com> CC: Alex Jacobson <alex@alexjacobson.com>, glasgow-haskell-users@haskell.org References: <47434E64.1070206@alexjacobson.com> <200711202239.57672.g9ks157k@acme.softbase.org> <474354D4.7010307@alexjacobson.com> <4743F6B4.9050505@gmail.com> <47447B2B.8090206@alexjacobson.com> <47454879.8040003@gmail.com> Or use a preprocessor that inserts a LANGUAGE pragma. :) On Nov 22, 2007 9:14 AM, Simon Marlow <simonmarhaskell@gmail.com <mailto:simonmarhaskell@gmail.com>> 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 _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users