Reorganisation of the source tree

[ghc-hetmet.git] / compiler / javaGen / Java.lhs

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+Anbstract syntax for Java subset that is the target of Mondrian.
+The syntax has been taken from "The Java Language Specification".
+
+(c) Erik Meijer & Arjan van IJzendoorn
+
+November 1999
+
+Major reworking to be usable for the intermeduate (GOO) language
+for the backend of GHC and to target languauges like Java sucessfully.
+-- Andy Gill
+
+\begin{code}
+module Java where
+
+\end{code}
+
+%************************************************************************
+%*                                                                     *
+\subsection{Java type declararations}
+%*                                                                     *
+%************************************************************************
+
+\begin{code}
+data CompilationUnit
+  = Package PackageName [Decl]
+    deriving (Show)
+    
+data Decl
+ = Import PackageName
+ | Field [Modifier] Name (Maybe Expr)
+ | Constructor [Modifier] TypeName [Parameter] [Statement]
+ | Method [Modifier] Name [Parameter] [Exception] [Statement]
+ | Comment [String]
+ | Interface [Modifier] TypeName [TypeName] [Decl]
+ | Class [Modifier] TypeName [TypeName] [TypeName] [Decl]
+   deriving (Show)
+
+data Parameter
+ = Parameter [Modifier] Name
+   deriving (Show)
+   
+data Statement
+  = Skip
+  | Return Expr                -- This always comes last in a list
+                       -- of statements, and it is understood
+                       -- you might change this to something
+                       -- else (like a variable assignment)
+                       -- if this is not top level statements.
+  | Block [Statement]
+  | ExprStatement Expr -- You are never interested in the result
+                       -- of an ExprStatement
+  | Declaration Decl -- variable = inner Field, Class = innerclass
+  | IfThenElse [(Expr,Statement)] (Maybe Statement)
+  | Switch Expr [(Expr, [Statement])] (Maybe [Statement])
+    deriving (Show)
+
+data Expr 
+  = Var Name
+  | Literal Lit
+  | Cast Type Expr
+  | Access Expr Name
+  | Assign Expr Expr
+  | InstanceOf Expr Type
+  | Call Expr Name [Expr]
+  | Op Expr String Expr
+  | Raise TypeName [Expr]
+  | New Type [Expr] (Maybe [Decl]) -- anonymous innerclass
+    deriving (Show)
+    
+data Modifier 
+  = Public | Protected | Private
+  | Static
+  | Abstract | Final | Native | Synchronized | Transient | Volatile
+  deriving (Show, Eq, Ord)
+
+-- A type is used to refer in general to the shape of things,
+-- or a specific class. Never use a name to refer to a class,
+-- always use a type.
+
+data Type 
+  = PrimType  PrimType
+  | ArrayType Type
+  | Type      TypeName
+    deriving (Show, Eq)
+
+data PrimType 
+  = PrimInt 
+  | PrimBoolean
+  | PrimChar
+  | PrimLong
+  | PrimFloat
+  | PrimDouble
+  | PrimByte
+  | PrimVoid
+    deriving (Show, Eq)
+
+type PackageName = String      -- A package name
+                               -- like "java.awt.Button"
+
+type Exception   = TypeName    -- A class name that must be an exception.
+
+type TypeName    = String      -- a fully qualified type name
+                               -- like "java.lang.Object".
+                               -- has type "Type <the name>"
+
+data Name        = Name String Type
+       deriving Show           -- A class name or method etc, 
+                               -- at defintion time,
+                               -- this generally not a qualified name.
+
+                               -- The type is shape of the box require
+                               -- to store an access to this thing.
+                               -- So variables might be Int or Object.
+
+                               --  ** method calls store the returned
+                               --  ** type, not a complete arg x result type.
+                               --
+                               -- Thinking:
+                               -- ... foo1.foo2(...).foo3 ...
+                               -- here you want to know the *result*
+                               -- after calling foo1, then foo2,
+                               -- then foo3.
+
+instance Eq Name where
+   (Name nm _) == (Name nm' _) = nm == nm'
+
+
+instance Ord Name where
+   (Name nm _) `compare` (Name nm' _) = nm `compare` nm'
+
+
+data Lit
+  = IntLit Integer     -- unboxed
+  | CharLit Int        -- unboxed
+  | StringLit String   -- java string
+  deriving Show
+
+addModifier :: Modifier -> Decl -> Decl
+addModifier = \m -> \d ->
+ case d of
+   { Import n -> Import n
+   ; Field ms n e -> Field (m:ms) n e  
+   ; Constructor ms n as ss -> Constructor (m:ms) n as ss
+   ; Method ms n as ts ss -> Method (m:ms) n as ts ss
+   ; Comment ss -> Comment ss
+   ; Interface ms n xs ds -> Interface (m:ms) n xs ds
+   ; Class ms n xs is ds -> Class (m:ms) n xs is ds
+   }
+
+changeNameType :: Type -> Name -> Name
+changeNameType ty (Name n _) = Name n ty
+   
+areSimple :: [Expr] -> Bool
+areSimple = \es -> all isSimple es
+
+isSimple :: Expr -> Bool
+isSimple = \e ->
+  case e of
+   { Cast t e -> isSimple e
+   ; Access e n -> isSimple e
+   ; Assign l r -> isSimple l && isSimple r
+   ; InstanceOf e t -> isSimple e
+   ; Call e n es -> isSimple e && areSimple es
+   ; Op e1 o e2 -> False
+   ; New n es Nothing -> areSimple es
+   ; New n es (Just ds) -> False
+   ; otherwise -> True
+   }
+\end{code}