module-management-0.9.3: Clean up module imports, split and merge modules

Safe HaskellNone

Language.Haskell.Modules

Description

This package provides three functions. The cleanImports function uses ghc's -ddump-minimal-imports flag to generate minimized and explicit imports and re-insert them into the module.

The splitModule moves each declaration of a module into a separate new module, and may also create three additional modules: ReExported (for identifiers that were re-exported from other imports), Instances (for declarations that don't result in an identifier to export), and OtherSymbols (for declarations that can't be turned into a module name.)

In addition to creating new modules, splitModule also scans the a set of modules (known as the moduVerse) and updates their imports to account for the new locations of the symbols. The moduVerse is stored in MonadClean's state, and is updated as modules are created and destroyed by splitModule and catModules.

The catModules function is the inverse operation of splitModule, it merges two or more modules into a new or existing module, updating imports of the moduVerse elements as necessary.

There are several features worth noting. The Params type in the state of MonadClean has a removeEmptyImports field, which is True by default. This determines whether imports that turn into empty lists are preserved or not - if your program needs instances from a such an import, you will either want to set this flag to False or (better) add an empty import list to the import.

These are the important entry points:

Examples:

  • Clean up the import lists of all the modules under ./Language:
findPaths "Language" >>= runMonadClean . mapM cleanImports . toList
  • Split up the module Common and then merge two of the pieces back in:
findModules "Language" >>= \ modules -> runMonadClean $
      let mn = Language.Haskell.Exts.Syntax.ModuleName in
      modifyModuVerse (const modules) >>
      splitModule (mn "Language.Haskell.Modules.Common") >>
      mergeModules (map mn ["Language.Haskell.Modules.Common.WithCurrentDirectory",
                            "Language.Haskell.Modules.Common.ModulePathBase"])
                   (mn "Language.Haskell.Modules.Common"))

Synopsis

Documentation

cleanImports :: MonadClean m => FilePath -> m ModuleResultSource

Clean up the imports of a source file.

splitModule :: MonadClean m => ModuleName -> m ()Source

Split each of a module's declarations into a new module. Update the imports of all the modules in the moduVerse to reflect the split.

mergeModules :: MonadClean m => [ModuleName] -> ModuleName -> m (Set ModuleResult)Source

Merge the declarations from several modules into a single new one, updating the imports of the modules in the moduVerse to reflect the change. It *is* permissable to use one of the input modules as the output module. Note that circular imports can be created by this operation.

findModules :: FilePath -> IO (Set ModuleName)Source

Convenience function for building the moduVerse, searches for files in a directory hierarchy, with a filter predicate.