Re: Distribution.PreProcess

On Tue, Dec 07, 2004 at 09:55:44AM -0800, Isaac Jones wrote:

Ross Paterson writes:

...

For Hugs, it would be more convenient to preprocess a source tree to make a new tree, especially if cpp turns Foo.hs into Foo.hs.

We originally had it move all the files into a temporary spot, then preprocss, then build. One problem with that, of course, is the threat of an IDE bringing up an error in one of the files that's been moved, the user fixing it, running the build again, and having the same error.

Perhaps you need two versions: - one for ghc and nhc98 that leaves the output of preprocessing in the same place, and doesn't run cpp. - one for Hugs that takes an extra argument, a directory to put the preprocessed files in, and also optionally runs cpp on each file after any other preprocessing. You could use the same list of suffix handlers for both if you defined type PPSuffixHandler = (String, Maybe PreProcessor) with Nothing meaning do nothing in the first case and copy (or cpp) in the second. (Haddock are another kettle of fish.) Also, in the Hugs case it would be helpful to return the list of names of the files created, because they may need subsequent compilation with ffihugs.