diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/9.4.1-notes.rst | 8 | ||||
| -rw-r--r-- | docs/users_guide/extending_ghc.rst | 29 |
2 files changed, 30 insertions, 7 deletions
diff --git a/docs/users_guide/9.4.1-notes.rst b/docs/users_guide/9.4.1-notes.rst index 39ab943356..3ccbf4c3ec 100644 --- a/docs/users_guide/9.4.1-notes.rst +++ b/docs/users_guide/9.4.1-notes.rst @@ -64,6 +64,12 @@ Compiler defaults for ambiguous variables that would otherwise cause errors just like the built-in defaulting mechanism. +- ``GHC.Plugins.parsedResultAction`` now takes and returns a tuple of warnings + and errors encountered by the parser before they're shown to the user, as + long as none of the errors prevented the AST from being built. This means + plugins can remove, modify, or add any of these, or simply pass them through + unchanged. + - The way GHC checks for representation polymorphism has been overhauled: all the checks are now done during typechecking. The error messages now contain more detailed information about the specific check that was performed. @@ -375,4 +381,4 @@ Compiler - GHC no longer carries ``Derived`` constraints. Accordingly, several functions in the plugin architecture that previously passed or received three sets of - constraints (givens, deriveds, and wanteds) now work with two such sets.
\ No newline at end of file + constraints (givens, deriveds, and wanteds) now work with two such sets. diff --git a/docs/users_guide/extending_ghc.rst b/docs/users_guide/extending_ghc.rst index a727d3ee60..4a987bca87 100644 --- a/docs/users_guide/extending_ghc.rst +++ b/docs/users_guide/extending_ghc.rst @@ -755,7 +755,8 @@ in the source code as well as the original syntax tree of the compiled module. :: parsed :: [CommandLineOption] -> ModSummary -> HsParsedModule - -> Hsc HsParsedModule + -> (Messages PsWarning, Messages PsError) + -> Hsc (HsParsedModule, (Messages PsWarning, Messages PsError) The ``ModSummary`` contains useful meta-information about the compiled module. The ``HsParsedModule`` contains the @@ -763,6 +764,14 @@ lexical and syntactical information we mentioned before. The result that you return will change the result of the parsing. If you don't want to change the result, just return the ``HsParsedModule`` that you received as the argument. +If the parser encounters any errors that prevent an AST from being constructed, +the plugin will not be run, but other kinds of errors, as well as warnings, +will be given to the plugin via the ``Messages`` tuple. This allows you to +modify, remove, and add warnings or errors before they are displayed to the +user, although in most cases, you will likely want to return the tuple +unmodified. The parsing pass will fail if the returned ``Messages PsError`` +collection is not empty after all parsing plugins have been run. + Type checked representation ^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -874,7 +883,7 @@ displayed. import Control.Monad.IO.Class import GHC.Driver.Session (getDynFlags) import GHC.Driver.Plugins - import GHC.Driver.Types + import GHC.Plugins import GHC.Tc.Types import Language.Haskell.Syntax.Extension import GHC.Hs.Decls @@ -893,11 +902,15 @@ displayed. , interfaceLoadAction = interfaceLoadPlugin } - parsedPlugin :: [CommandLineOption] -> ModSummary -> HsParsedModule -> Hsc HsParsedModule - parsedPlugin _ _ pm - = do dflags <- getDynFlags + parsedPlugin :: [CommandLineOption] -> ModSummary -> HsParsedModule + -> (Messages PsWarning, Messages PsError) + -> Hsc (HsParsedModule, (Messages PsWarning, Messages PsError)) + parsedPlugin _ _ pm msgs@(warns, errs) + = do dflags <- getDynFlags liftIO $ putStrLn $ "parsePlugin: \n" ++ (showSDoc dflags $ ppr $ hpm_module pm) - return pm + liftIO $ putStrLn $ "parsePlugin warnings: \n" ++ (showSDoc dflags $ ppr warns) + liftIO $ putStrLn $ "parsePlugin errors: \n" ++ (showSDoc dflags $ ppr errs) + return (pm, msgs) renamedAction :: [CommandLineOption] -> TcGblEnv -> HsGroup GhcRn -> TcM (TcGblEnv, HsGroup GhcRn) renamedAction _ tc gr = do @@ -945,6 +958,10 @@ output: module A where a = () $(return []) + parsePlugin warnings: + + parsePlugin errors: + typeCheckPlugin (rn): a = () interface loaded: Language.Haskell.TH.Lib.Internal meta: return [] |