Re: [Haskell-cafe] Why isn't hsc2hs functionality provided by ghc?

cabal-dev ghci does work with hsc2hs, but only because it doesn't interpret your source. Rather, cabal-dev ghci loads ghci using the sandbox install of your package, which is less useful for a variety of reasons. Aside from that detail, I wouldn't gain any benefit from having this feature built in to ghci instead of accessing ghci via cabal (or cabal-dev). cabal seems like a better location, and it's aware of several preprocessors already. On Wed, Jun 5, 2013 at 12:00 PM, Jason Dagit wrote:

On Tue, Jun 4, 2013 at 8:45 PM, John Lato wrote:

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On Wed, Jun 5, 2013 at 10:15 AM, Ivan Lazar Miljenovic wrote:

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On 5 June 2013 12:02, silly8888 wrote:

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I was wondering today, why hasn't hsc2hs been merged with ghc so that it would be possible to add a

{-# LANGUAGE ForeignFunctionInterface #-}

at the top of a source file and then load it with ghci or compile it, without the intermediate step of calling hsc2hs? This would be exactly like the CPP extension. I don't have to call cpp manually. All I have to do is to add {-# LANGUAGE CPP #-} and then ghc will take care of the rest. This would also mean that there would be no need to have a separate file extension. Surely I must not be the first person to have that thought, so there must be a good reason why this hasn't happen yet, but what is it?

Isn't this done automatically when you have files with the .hsc

extension?

cabal handles this transparently, but not ghc. It's frustrating when you want to develop a project with ghci.

I don't think it's a good idea to merge hsc2hs syntax into Haskell files. In particular, it's often useful to inspect the intermediate .hs file produced by hsc2hs during development or debugging. Also it would complicate ghc's parser, etc...

My preferred solution would be to have ghc/ghci automatically run hsc2hs (support c2hs also?) when necessary. But so long as it's handled automatically, I wouldn't be particularly bothered by the implementation.

How about having a `ghci` command for cabal? Or does the automatic requirement really need to be part of ghc to work the way you want?

(BTW, cabal-dev does have a `ghci` command, but I haven't tested to see if it does the hsc -> hs conversion.)

Jason