redefine :r in cabal repl to run preprocessors (#1580) #1726
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/cc @dcoutts who's done some of the earlier work on this. |
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I will review this tonight I hope. @23Skidoo does this look OK to you? |
| let dotGhciPath = autogenModulesDir lbi </> "ghci" | ||
| rewriteFile dotGhciPath (unlines | ||
| ["-- override :reload", | ||
| ":def! r (\\_ -> return \":!cabal build --only-preprocess\\n::reload\")"]) |
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Should this be :def! r so this works if the user actually types the full command? Or does :def! r actually use the same lookup rules that makes :r mean :reload?
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At least in my ghci (7.6.2), macros only work by the exact name they are defined with. Furthermore :def! reload (\_ -> return "somethingNotInScope\n::reload") ought to break :reload, but it seems the built-in :reload is used instead.
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Please read all of https://ghc.haskell.org/trac/ghc/ticket/8113, including the other ticket linked to at the end.
We can probably only make this work correctly in GHC 7.8. So either
- we guard this behind a GHC version check and only pass the extra ghci script to GHC-7.8 or later or
- we define the macro as
reloadwhen using GHC-7.8 or later and ascabal-reloadotherwise.
The latter will let all users use the features, but it won't magically work correctly with e.g. the Haskell emacs mode.
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Looks good to me in general, modulo some comments. Thanks for your contribution! |
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@aavogt this would be great to have in 1.20. There are mostly minor comments and some testing needed to make sure this work on different GHCs. |
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cabal should detect when no preprocessors are required, and not redefine |
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I still want something like this in Cabal. Since there have been outstanding unaddressed review comments for a while and I'd like to keep our pull request queue clean, I will close this for now. |
This works for my purposes. It is a bit rough:
:radditionally prints things likeBuilding foo-0...\nPreprocessing library foo-0...:rcan be used (when nobuild-tools:are specified?)