Migration guide for SetupHooks, especially hookedPreProcessors

[Bodigrim]

I've been looking how to migrate from build-type: Custom to build-type: Hooks, but did not succeed. Most of the packages I'm interested in run hookedPreProcessors; what is supposed to be employed instead?

[sheaf]

Most of the documentation for using build-type: Hooks is in the Haddocks for the Cabal-hooks library. Unfortunately, it is not yet on Hackage, because Cabal 3.14 has not yet been released.
I have a mirror here which should tide you over in the meantime.

I also have a few examples of how custom preprocessors work with Hooks, see e.g. this example.

The idea is:

• in the pre-configure package-wide hook, configure a preprocessor (adding it to the Cabal program database);
• in the pre-build rules hook, do a search for which files to run the preprocessor on, and register a rule for each such file, that runs the preprocessor with appropriate arguments.

Where would you have expected to find information? I would be happy to contribute a migration guide, but I don't know where it would be most visible. I agree that this information is not very discoverable right now.

[Bodigrim]

Thanks for the links, but I'm afraid it is still quite a lot for me to grasp.

Here is a simple usage of hookedPreProcessors similar to what I have in other projects: https://hackage.haskell.org/package/Euterpea-2.0.7/src/Setup.hs. What would be an equivalent definition using hooks?

[sheaf]

Thanks for the links, but I'm afraid it is still quite a lot for me to grasp.

Here is a simple usage of hookedPreProcessors similar to what I have in other projects: https://hackage.haskell.org/package/Euterpea-2.0.7/src/Setup.hs. What would be an equivalent definition using hooks?

Pretty much identical to the example I linked. So something like:

setupHooks :: SetupHooks
setupHooks =
  noSetupHooks
    { configureHooks = Just configureCcap
    , buildHooks = Just runCcap }

where configureCcap calls findProgramLocation verbosity "ccap" and adds it to the program database, while runCcap does a search for *.as files, and registers a rule for each file that runs ccap on it.

The main difference is that the user is in charge of doing the search for *.as files, as opposed to declaratively specifying that the preprocessor handles any file with *.as file extension. (It would be straightforward to write a bit of library code that handles this common case and include that in the Cabal-hooks library.)

[Bodigrim]

Got it, thanks!

(It would be straightforward to write a bit of library code that handles this common case and include that in the Cabal-hooks library.)

I think it's a common pattern, worth introducion of a helper.