Auto-attach type declarations to their values.

src/Bang/AST/Declaration.hs

@@ -31,7 +31,7 @@ import Bang.Utils.Pretty(text')
 import Data.Text.Lazy(Text)
 import Control.Lens(Lens', view, set, lens)
 import Control.Lens(makeLenses)
-import Text.PrettyPrint.Annotated(Doc, text, (<+>))
+import Text.PrettyPrint.Annotated(Doc, text, (<+>), ($+$), empty)
 
 data TypeDeclaration = TypeDeclaration
      { _tdName     :: Name
@@ -69,8 +69,13 @@ class MkValueDecl a where
   mkValueDecl :: Name -> Location -> Expression -> a
 
 ppValueDeclaration :: ValueDeclaration -> Doc a
-ppValueDeclaration vd =
-  ppName (_vdName vd) <+> text "=" <+> ppExpression (_vdValue vd)
+ppValueDeclaration vd = typedecl $+$ valuedecl
+ where
+  typedecl
+    | Just dt <- _vdDeclaredType vd =
+        ppTypeDeclaration (TypeDeclaration (_vdName vd) (_vdLocation vd) dt)
+    | otherwise = empty
+  valuedecl = ppName (_vdName vd) <+> text "=" <+> ppExpression (_vdValue vd)
 
 instance MkValueDecl ValueDeclaration where
   mkValueDecl n l e = ValueDeclaration n l [] [] Nothing e

src/Bang/Syntax/PostProcess.hs

@@ -1,15 +1,105 @@
 module Bang.Syntax.PostProcess(
          runPostProcessor
        )
+ where
 
-import Bang.Syntax.AST
+import           Bang.AST(Name, Module, moduleDeclarations, ppName)
+import           Bang.AST.Declaration(Declaration(..), declName,
+                                      TypeDeclaration, ValueDeclaration,
+                                      tdName, tdLocation, tdType,
+                                      vdName, vdLocation, vdDeclaredType)
+import           Bang.Monad(Compiler, BangError(..), err)
+import           Bang.Syntax.Location(Location, ppLocation)
+import           Bang.Utils.Pretty(BangDoc)
+import           Control.Lens(view, set)
+import           Control.Monad(foldM)
+import           Data.Map.Strict(Map)
+import qualified Data.Map.Strict as Map
+import           Text.PrettyPrint.Annotated(text, ($+$), (<+>), nest)
+
+data PostProcessError = InternalError        Name
+                      | RedefinitionError    Name Location Location
+                      | TypeDeclWithoutValue Name Location
+ deriving (Show)
+
+instance BangError PostProcessError where
+  ppError = prettyError
+
+prettyError :: PostProcessError -> (Maybe Location, BangDoc)
+prettyError e =
+  case e of
+    InternalError n ->
+      (Nothing, text "Serious post-processing error w.r.t. " <+> ppName n)
+    RedefinitionError n l1 l2 ->
+      (Just l1, text "Name" <+> ppName n <+> text "redefined." $+$
+                nest 2 (text "original definiton at " <+> ppLocation l2))
+    TypeDeclWithoutValue n l ->
+      (Just l, text "Type declaration provided, but no value provided." $+$
+               nest 2 (text "variable name: " <+> ppName n))
 
 runPostProcessor :: Module -> Compiler ps Module
-runPostProcessor mod = undefined
+runPostProcessor mdl =
+  do declTable <- makeDeclarationTable mdl
+     mdl' <- combineTypeValueDeclarations declTable mdl
+     return mdl'
 
 -- -----------------------------------------------------------------------------
 
 type DeclarationTable = Map Name (Maybe TypeDeclaration, Maybe ValueDeclaration)
 
-makeDeclarationTable :: Module -> DeclarationTable
+makeDeclarationTable :: Module -> Compiler ps DeclarationTable
+makeDeclarationTable m = foldM combine Map.empty (view moduleDeclarations m)
+ where
+  combine table d =
+    do let name = view declName d
+       case d of
+         DeclType td ->
+           case Map.lookup name table of
+             Nothing            ->
+               return (Map.insert name (Just td, Nothing) table)
+             Just (Nothing, vd) ->
+               return (Map.insert name (Just td, vd) table)
+             Just (Just td', _) ->
+               do let newLoc  = view tdLocation td
+                      origLoc = view tdLocation td'
+                  err (RedefinitionError name newLoc origLoc)
+         DeclVal vd ->
+           case Map.lookup name table of
+             Nothing            ->
+               return (Map.insert name (Nothing, Just vd) table)
+             Just (td, Nothing) ->
+               return (Map.insert name (td, Just vd) table)
+             Just (_, Just vd') ->
+               do let newLoc  = view vdLocation vd
+                      origLoc = view vdLocation vd'
+                  err (RedefinitionError name newLoc origLoc)
+         DeclPrim _ ->
+           return table
 
+-- -----------------------------------------------------------------------------
+
+combineTypeValueDeclarations :: DeclarationTable -> Module -> Compiler ps Module
+combineTypeValueDeclarations table m =
+  do let decls = view moduleDeclarations m
+     decls' <- process decls
+     return (set moduleDeclarations decls' m)
+ where
+  process [] = return []
+  process (x:rest) =
+    case x of
+      DeclPrim _  -> (x:) `fmap` process rest
+      DeclType td ->
+        case Map.lookup (view tdName td) table of
+          Just (_, Nothing) ->
+            err (TypeDeclWithoutValue (view tdName td) (view tdLocation td))
+          _ ->
+            process rest
+      DeclVal vd ->
+        case Map.lookup (view vdName vd) table of
+          Nothing ->
+            err (InternalError (view vdName vd))
+          Just (Nothing, _) ->
+            (x:) `fmap` process rest
+          Just (Just td, _) ->
+            do let vd' = set vdDeclaredType (Just (view tdType td)) vd
+               (DeclVal vd' :) `fmap` process rest 

src/Bang/TypeInfer.hs

@@ -3,8 +3,12 @@
 module Bang.TypeInfer(runTypeInference)
  where
 
-runTypeInference :: a
-runTypeInference = undefined
+import Bang.AST(Module)
+import Bang.Monad(Compiler)
+import Bang.Syntax.ParserMonad(NameDatabase)
+
+runTypeInference :: NameDatabase -> Module -> Compiler ps Module
+runTypeInference _ x = return x
 
 {- Better version 
 import           Bang.Monad(Compiler, BangError(..), err,

src/Main.hs

@@ -2,6 +2,7 @@ import           Bang.CommandLine(getCommand, BangCommand(..), helpString)
 import           Bang.AST(ppModule)
 import           Bang.Monad(runCompiler)
 import           Bang.Syntax.Parser(runParser, parseModule)
+import           Bang.Syntax.PostProcess(runPostProcessor)
 import           Bang.TypeInfer(runTypeInference)
 import           Data.Version(showVersion)
 import           Paths_bang(version)
@@ -14,7 +15,8 @@ main = getCommand >>= \ cmd ->
                       putStrLn (render (ppModule mdl))
     TypeCheck o -> do mdl <- runCompiler cmd o (\ r t ->
                                                  do (ndb, mdl) <- runParser r t parseModule
-                                                    runTypeInference ndb mdl)
+                                                    mdl' <- runPostProcessor mdl
+                                                    runTypeInference ndb mdl')
                       putStrLn (render (ppModule mdl))
     Help        -> putStrLn helpString
     Version     -> putStrLn ("Bang tool, version " ++ showVersion version)