Added aliased import

CHANGES.md

@@ -118,6 +118,15 @@ To be released.
  -  Fixed a compiler bug that an error message on name duplicates had referred
     to a wrong line/column number.  [[#255]]
 
+ -  Added aliased import.  It's handy to avoid a name shadowing.
+    [[#217], [#258]]
+
+    ~~~~~~~~ nirum
+    import iso (country as iso-country);
+    import types (country);
+    ~~~~~~~~
+
+
 ### Docs target
 
  -  A new required configuration `targets.docs.title` was added.
@@ -175,12 +184,14 @@ To be released.
     March 2018.
 
 [#13]: https://github.com/spoqa/nirum/issues/13
+[#217]: https://github.com/spoqa/nirum/issues/217
 [#220]: https://github.com/spoqa/nirum/issues/220
 [#227]: https://github.com/spoqa/nirum/pull/227
 [#253]: https://github.com/spoqa/nirum/pull/253
 [#254]: https://github.com/spoqa/nirum/pull/254
 [#255]: https://github.com/spoqa/nirum/pull/255
 [#257]: https://github.com/spoqa/nirum/pull/257
+[#258]: https://github.com/spoqa/nirum/pull/258
 [#259]: https://github.com/spoqa/nirum/pull/259
 [entry points]: https://setuptools.readthedocs.io/en/latest/pkg_resources.html#entry-points
 [python2-numbers-integral]: https://docs.python.org/2/library/numbers.html#numbers.Integral

examples/address.nrm

@@ -1,4 +1,5 @@
 import countries (country);
+import geo (geo as geo-point);
 
 record address (
     float32 lat,
@@ -8,3 +9,8 @@ record address (
     country country,
     text postal-code,
 );
+
+
+record pin (
+    geo-point geo,
+);

examples/countries.nrm

@@ -6,7 +6,7 @@ enum country
     | ax  # Åland Islands
     | al  # Albania
     | dz  # Algeria
-    | as  # American Samoa
+    | `as`  # American Samoa
     | ad  # Andorra
     | ao  # Angola
     | ai  # Anguilla

examples/geo.nrm

@@ -0,0 +1,4 @@
+record geo (
+    float32 latitude,
+    float32 longitude,
+);

src/Nirum/Constructs/Identifier.hs

@@ -62,6 +62,7 @@ reservedKeywords = [ "enum"
                    , "unboxed"
                    , "union"
                    , "default"
+                   , "as"
                    ]
 
 identifierRule :: P.Parsec Void T.Text Identifier

src/Nirum/Constructs/Module.hs

@@ -57,10 +57,18 @@ instance Construct Module where
       where
         typeList :: [TypeDeclaration]
         typeList = DS.toList types'
+        importIdentifiersToCode :: (Identifier, Identifier) -> T.Text
+        importIdentifiersToCode (i, s) = if i == s
+                                            then toCode i
+                                            else T.concat [ toCode s
+                                                          , " as "
+                                                          , toCode i
+                                                          ]
         importCodes :: [T.Text]
         importCodes =
             [ T.concat [ "import ", toCode p, " ("
-                       , T.intercalate ", " $ map toCode $ S.toAscList i
+                       , T.intercalate ", " $
+                           map importIdentifiersToCode $ S.toAscList i
                        , ");"
                        ]
             | (p, i) <- M.toAscList (imports m)
@@ -76,9 +84,9 @@ instance Construct Module where
 instance Documented Module where
     docs (Module _ docs') = docs'
 
-imports :: Module -> M.Map ModulePath (S.Set Identifier)
+imports :: Module -> M.Map ModulePath (S.Set (Identifier, Identifier))
 imports (Module decls _) =
-    M.fromListWith S.union [(p, [i]) | Import p i _ <- DS.toList decls]
+    M.fromListWith S.union [(p, [(i, s)]) | Import p i s _ <- DS.toList decls]
 
 coreModulePath :: ModulePath
 coreModulePath = ["core"]

src/Nirum/Constructs/TypeDeclaration.hs

@@ -49,6 +49,7 @@ module Nirum.Constructs.TypeDeclaration ( EnumMember (EnumMember)
                                                           , service
                                                           , serviceAnnotations
                                                           , serviceName
+                                                          , sourceName
                                                           , type'
                                                           , typeAnnotations
                                                           , typename
@@ -191,6 +192,7 @@ data TypeDeclaration
                          }
     | Import { modulePath :: ModulePath
              , importName :: Identifier
+             , sourceName :: Identifier
              , importAnnotations :: AnnotationSet
              }
     deriving (Eq, Ord, Show)
@@ -285,13 +287,16 @@ instance Construct TypeDeclaration where
         methodsText = T.intercalate "\n" $ map toCode methods'
         docs' :: Maybe Docs
         docs' = A.lookupDocs annotations'
-    toCode (Import path ident aSet) = T.concat [ "import "
-                                               , toCode path
-                                               , " ("
-                                               , toCode aSet
-                                               , toCode ident
-                                               , ");\n"
-                                               ]
+    toCode (Import path iName sName aSet) = T.concat
+        [ "import "
+        , toCode path
+        , " ("
+        , toCode aSet
+        , if iName == sName
+             then toCode iName
+             else T.concat [ toCode sName, " as ", toCode iName ]
+        , ");\n"
+        ]
 
 instance Documented TypeDeclaration
 

src/Nirum/Package/ModuleSet.hs

@@ -90,12 +90,12 @@ detectMissingImports moduleSet =
                 Nothing -> [MissingModulePathError path path']
                 Just (Module decls _) ->
                     [ e
-                    | i <- S.toList idents
-                    , e <- case DS.lookup i decls of
+                    | (_, s) <- S.toList idents
+                    , e <- case DS.lookup s decls of
                         Just TypeDeclaration {} -> []
                         Just ServiceDeclaration {} -> []
-                        Just Import {} -> [MissingImportError path path' i]
-                        Nothing -> [MissingImportError path path' i]
+                        Just Import {} -> [MissingImportError path path' s]
+                        Nothing -> [MissingImportError path path' s]
                     ]
         ]
 

src/Nirum/Parser.hs

@@ -11,6 +11,7 @@ module Nirum.Parser ( Parser
                     , handleNameDuplication
                     , handleNameDuplicationError
                     , identifier
+                    , importName
                     , imports
                     , listModifier
                     , mapModifier
@@ -32,7 +33,7 @@ module Nirum.Parser ( Parser
                     , unionTypeDeclaration
                     ) where
 
-import Control.Monad (void, when)
+import Control.Monad (unless, void, when)
 import Data.Void
 import qualified System.IO as SIO
 
@@ -627,28 +628,49 @@ modulePath = do
     f Nothing i = Just $ ModuleName i
     f (Just p) i = Just $ ModulePath p i
 
-importName :: Parser (Identifier, A.AnnotationSet)
-importName = do
+importName :: [Identifier]
+           -> Parser (Identifier, Identifier, A.AnnotationSet)
+importName forwardNames = do
     aSet <- annotationSet <?> "import annotations"
     spaces
     iName <- identifier <?> "name to import"
-    return (iName, aSet)
+    hasAlias <- optional $ try $ do
+        spaces
+        string' "as"
+    aName <- case hasAlias of
+        Just _ -> do
+            spaces
+            uniqueIdentifier forwardNames "alias name to import"
+        Nothing ->
+            return iName
+    return (aName, iName, aSet)
 
-imports :: Parser [TypeDeclaration]
-imports = do
+imports :: [Identifier] -> Parser [TypeDeclaration]
+imports forwardNames = do
     string' "import" <?> "import keyword"
     spaces
     path <- modulePath <?> "module path"
     spaces
     char '('
     spaces
-    idents <- (importName >>= \ i -> spaces >> return i)
-        `sepEndBy1` (char ',' >> spaces)
-        <?> "names to import"
+    idents <- many' [] $ \ importNames' -> do
+        notFollowedBy $ choice [char ')', char ',' >> spaces >> char ')']
+        let forwardNames' = [i | (i, _, _) <- importNames'] ++ forwardNames
+        unless (L.null importNames') $ do
+            string' ","
+            spaces
+        n <- importName forwardNames'
+        spaces
+        return n
+    when (L.null idents) $ fail "parentheses cannot be empty"
+    void $ optional $ string' ","
+    spaces
     char ')'
     spaces
     char ';'
-    return [Import path ident aSet | (ident, aSet) <- idents]
+    return [ Import path imp source aSet
+           | (imp, source, aSet) <- idents
+           ]
 
 
 module' :: Parser Module
@@ -660,7 +682,7 @@ module' = do
         return d
     spaces
     importLists <- many $ do
-        importList <- imports
+        importList <- imports []
         spaces
         return importList
     let imports' = [i | l <- importLists, i <- l]

src/Nirum/Targets/Python/Serializers.hs

@@ -39,22 +39,22 @@ compileSerializer mod' (TypeIdentifier typeId) pythonVar =
     case lookupType typeId mod' of
         Missing -> "None"  -- must never happen
         Local (Alias t) -> compileSerializer mod' t pythonVar
-        Imported modulePath' (Alias t) ->
+        Imported modulePath' _ (Alias t) ->
             case resolveBoundModule modulePath' (boundPackage mod') of
                 Nothing -> "None"  -- must never happen
                 Just foundMod -> compileSerializer foundMod t pythonVar
         Local PrimitiveType { primitiveTypeIdentifier = p } ->
             compilePrimitiveTypeSerializer p pythonVar
-        Imported _ PrimitiveType { primitiveTypeIdentifier = p } ->
+        Imported _ _ PrimitiveType { primitiveTypeIdentifier = p } ->
             compilePrimitiveTypeSerializer p pythonVar
         Local EnumType {} -> serializerCall
-        Imported _ EnumType {} -> serializerCall
+        Imported _ _ EnumType {} -> serializerCall
         Local RecordType {} -> serializerCall
-        Imported _ RecordType {} -> serializerCall
+        Imported _ _ RecordType {} -> serializerCall
         Local UnboxedType {} -> serializerCall
-        Imported _ UnboxedType {} -> serializerCall
+        Imported _ _ UnboxedType {} -> serializerCall
         Local UnionType {} -> serializerCall
-        Imported _ UnionType {} -> serializerCall
+        Imported _ _ UnionType {} -> serializerCall
   where
     serializerCall :: Code
     serializerCall = [qq|$pythonVar.__nirum_serialize__()|]

src/Nirum/Targets/Python/TypeExpression.hs

@@ -22,9 +22,12 @@ compileTypeExpression :: BoundModule Python
 compileTypeExpression mod' (Just (TypeIdentifier i)) =
     case lookupType i mod' of
         Missing -> fail $ "undefined identifier: " ++ toString i
-        Imported _ (PrimitiveType p _) -> compilePrimitiveType p
-        Imported m _ -> do
-            insertThirdPartyImports [(toImportPath target' m, [toClassName i])]
+        Imported _ _ (PrimitiveType p _) -> compilePrimitiveType p
+        Imported m in' _ -> do
+            insertThirdPartyImportsA [ ( toImportPath target' m
+                                       , [(toClassName i, toClassName in')]
+                                       )
+                                     ]
             return $ toClassName i
         Local _ -> return $ toClassName i
   where

src/Nirum/Targets/Python/Validators.hs

@@ -65,13 +65,13 @@ compileValidator mod' (TypeIdentifier typeId) pythonVar =
     case lookupType typeId mod' of
         Missing -> return $ Validator "False" []  -- must never happen
         Local (Alias typeExpr') -> compileValidator mod' typeExpr' pythonVar
-        Imported modulePath' (Alias typeExpr') ->
+        Imported modulePath' _ (Alias typeExpr') ->
             case resolveBoundModule modulePath' (boundPackage mod') of
                 Nothing -> return $ Validator "False" []  -- must never happen
                 Just foundMod -> compileValidator foundMod typeExpr' pythonVar
         Local PrimitiveType { primitiveTypeIdentifier = pId } ->
             compilePrimitiveTypeValidator pId pythonVar
-        Imported _ PrimitiveType { primitiveTypeIdentifier = pId } ->
+        Imported _ _ PrimitiveType { primitiveTypeIdentifier = pId } ->
             compilePrimitiveTypeValidator pId pythonVar
         _ ->
             compileInstanceValidator mod' typeId pythonVar

src/Nirum/TypeInstance/BoundModule.hs

@@ -47,25 +47,28 @@ boundTypes = findInBoundModule types DS.empty
 
 data TypeLookup = Missing
                 | Local Type
-                | Imported ModulePath Type
+                | Imported ModulePath Identifier Type
                 deriving (Eq, Ord, Show)
 
 lookupType :: Target t => Identifier -> BoundModule t -> TypeLookup
 lookupType identifier boundModule =
     case DS.lookup identifier (boundTypes boundModule) of
-        Nothing -> toType coreModulePath
-            (DS.lookup identifier $ types coreModule)
+        Nothing ->
+            toType
+                coreModulePath
+                identifier
+                (DS.lookup identifier $ types coreModule)
         Just TypeDeclaration { type' = t } -> Local t
-        Just (Import path' _ _) ->
+        Just (Import path' _ s _) ->
             case resolveModule path' (boundPackage boundModule) of
                 Nothing -> Missing
                 Just (Module decls _) ->
-                    toType path' (DS.lookup identifier decls)
+                    toType path' s (DS.lookup s decls)
         Just ServiceDeclaration {} -> Missing
   where
-    toType :: ModulePath -> Maybe TypeDeclaration -> TypeLookup
-    toType mp (Just TypeDeclaration { type' = t }) = Imported mp t
-    toType _ _ = Missing
+    toType :: ModulePath -> Identifier -> Maybe TypeDeclaration -> TypeLookup
+    toType mp i (Just TypeDeclaration { type' = t }) = Imported mp i t
+    toType _ _ _ = Missing
 
 instance Target t => Documented (BoundModule t) where
     docs = findInBoundModule Nirum.Constructs.Module.docs Nothing

test/Nirum/CodeBuilderSpec.hs

@@ -79,9 +79,9 @@ spec = do
             let run' = fst . runBuilder package ["fruits"] ()
             let core = ModuleName "core"
             run' (lookupType "text") `shouldBe`
-                Imported core (TD.PrimitiveType TD.Text TD.String)
+                Imported core "text" (TD.PrimitiveType TD.Text TD.String)
             run' (lookupType "int32") `shouldBe`
-                Imported core (TD.PrimitiveType TD.Int32 TD.Number)
+                Imported core "int32" (TD.PrimitiveType TD.Int32 TD.Number)
 
 
 data DummyTarget = DummyTarget deriving (Eq, Ord, Show)

test/Nirum/Constructs/ModuleSpec.hs

@@ -21,20 +21,27 @@ spec =
             pathT = TypeDeclaration "path" (Alias "text") (singleton docsAnno)
             offsetT =
                 TypeDeclaration "offset" (UnboxedType "float64") empty
-            decls = [ Import ["foo", "bar"] "baz" empty
-                    , Import ["foo", "bar"] "qux" empty
-                    , Import ["zzz"] "qqq" empty
-                    , Import ["zzz"] "ppp" empty
-                    , Import ["xyz"] "asdf" empty
+            decls = [ Import ["foo", "bar"] "baz" "baz" empty
+                    , Import ["foo", "bar"] "qux" "qux" empty
+                    , Import ["zzz"] "qqq" "qqq" empty
+                    , Import ["zzz"] "ppp" "ppp" empty
+                    , Import ["xyz"] "asdf" "asdf" empty
                     , pathT
                     , offsetT
                     ] :: DeclarationSet TypeDeclaration
+            decls2 = [ Import ["foo", "bar"] "qux" "baz" empty
+                     ] :: DeclarationSet TypeDeclaration
             mod1 = Module decls Nothing
             mod2 = Module decls $ Just "module level docs...\nblahblah"
+            mod3 = Module decls2 Nothing
         specify "imports" $ do
-            imports mod1 `shouldBe` [ (["foo", "bar"], ["baz", "qux"])
-                                    , (["xyz"], ["asdf"])
-                                    , (["zzz"], ["qqq", "ppp"])
+            imports mod1 `shouldBe` [ ( ["foo", "bar"]
+                                      , [("baz", "baz"), ("qux", "qux")]
+                                      )
+                                    , (["xyz"], [("asdf", "asdf")])
+                                    , ( ["zzz"]
+                                      , [("qqq", "qqq"), ("ppp", "ppp")]
+                                      )
                                     ]
             imports mod2 `shouldBe` imports mod1
         specify "toCode" $ do
@@ -57,4 +64,8 @@ type path = text;
 # path string
 
 unboxed offset (float64);
+|]
+            toCode mod3 `shouldBe` [q|import foo.bar (baz as qux);
+
+
 |]