#95: GHCi :edit command should jump to the the last error -------------------------------+------------------------------------------- Reporter: | Owner: lortabac martijnislief | Status: patch Type: feature | Milestone: ⊥ request | Version: None Priority: normal | Keywords: Component: GHCi | Architecture: Unknown/Multiple Resolution: None | Difficulty: Easy (less than 1 hour) Operating System: | Blocked By: Unknown/Multiple | Related Tickets: Type of failure: | None/Unknown | Test Case: | Blocking: | -------------------------------+------------------------------------------- Comment (by nomeata): Better! So time for the next round of suggestions. I found this code confusing {{{ let ... setGhciErrors e = writeIORef lastErrLocations (errs ++ e) setGhciErrors $ errLocation srcSpan }}} why not {{{ let ... writeIORef lastErrLocations (errs ++ errLocation srcSpan) }}} In fact I find the whole section there a bit strange. Some suggestions: * Use `modifyIORef` * Write something like {{{ case srcSpan of RealSrcSpan rsp -> modifyIORef lastErrLocations (++ [srcLocFile (realSrcSpanStart x) , srcLocLine (realSrcSpanStart x) ]) _ -> return () }}} so you don’t have to introduce so many local functions and do tricks with `++ []`. * `find (\(f, _) -> f == mkFastString file) errs` can even simplified to `lookup (mkFastSTring file)` I would put {{{ ghciState <- lift getGHCiState liftIO $ writeIORef (lastErrorLocations ghciState) [] }}} in a function `resetLastErrorLocations :: GHCi ()`. Naming that code also serves as documentation, and you don’t clutter the local name space of `doLoad` with the `ghciState` I wonder if things work well if the user uses a different path to the filename than GHC; maybe one wants to use a function that can check if two filenames point to the same file. But maybe that is a refinement that can be added later. Can you come up with a way to test this? Maybe by setting the editor to use to `/bin/echo`, which will put `+123` in the output that the test suite would check? See [Building/RunningTests/Adding] and shout if you need help creating a test case. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/95#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler