interpreter compiles

[proglang.git] / Interpret.hs

diff --git a/Interpret.hs b/Interpret.hs
index 8cf3c1b2657270d016c8f28256b993adbd566c96..b82398d22bc63b114eb0d5c6f7f344f80cd34c31 100644 (file)
--- a/Interpret.hs
+++ b/Interpret.hs
@@ -1,10 +1,12 @@
-module Interpret (eval, execute, Value(VInt, VBool)) where
+module Interpret (eval, execute,addFunction, emptyState, Value(..), State(..)) where
 
 import Abssyntax
-import Control.Monad.State
+import Control.Monad.State hiding (State)
 import Data.Map as Map
 import Prelude hiding (lookup)
 
+emptyState = State{variables=[empty], functions=(empty)}
+
 data Value = VInt Integer | VBool Bool deriving Eq
 
 instance Show Value where
@@ -13,13 +15,16 @@ instance Show Value where
        show (VBool False) = "0"
 
 type Variables = [Map Ident Value]
+type Function = ([Decl],[Stm])
+
+data State = State {variables::Variables,functions::(Map Ident Function)}
 
 inList :: Eq a => a -> [a] -> Bool
 inList _ [] = False
 inList a (x:xs) = if a == x then True else inList a xs
 
 --eval :: (MonadState Variables m) => Exp -> m Value
-eval :: Exp -> StateT Variables IO Value
+eval :: Exp -> StateT State IO Value
 eval (EBool b) = return (VBool b)
 eval (EInt n) = return (VInt n)
 eval (EVar i) = getVariableValue i
@@ -67,37 +72,37 @@ op ELt = \e e' -> VBool $ e <= e'
 op Gt = \e e' -> VBool $ e > e'
 op EGt = \e e' -> VBool $ e >= e'
 
-getVariableValue :: (MonadState Variables m) => Ident -> m Value 
+getVariableValue :: (MonadState State m) => Ident -> m Value 
 getVariableValue i = do
-       ms <- get 
-       findVariable i ms
+       s <- get 
+       findVariable i $ variables s
 
-findVariable :: (MonadState  Variables m) => Ident -> Variables -> m Value
+findVariable :: (MonadState State m) => Ident -> Variables -> m Value
 findVariable i [] = fail $ "Variable "++show i++" not found in any scope."
 findVariable i (m:ms) = if member i m then lookup i m else findVariable i ms
 
 --setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value 
 --setVariableValue :: (MonadState Variables m) => Ident -> Exp -> m Value 
 
-setVariableValue :: Ident -> Exp -> StateT Variables IO Value
+setVariableValue :: Ident -> Exp -> StateT State IO Value
 setVariableValue i e = do
        v <- eval e
-       ms <- get
-       put $ updateVariable i v ms
+       state <- get
+       modify (\s -> s{variables= updateVariable i v $ variables state} )
        return v
 
 updateVariable :: Ident -> Value -> Variables -> Variables 
 updateVariable _ _ [] = []
 updateVariable i v (m:ms) = if member i m then insert i v m:ms else m:updateVariable i v ms
 
-pushAndPop :: (MonadState Variables m) => m a -> m ()
+pushAndPop :: (MonadState State m) => m a -> m ()
 pushAndPop s = do
-       modify (empty:)
+       modify (\s -> s { variables = empty:variables s})
        s
-       modify tail
+       modify (\s -> s { variables = tail $ variables s})
 
 -- execute :: (MonadState Variables m) => Stm -> m ()
-execute :: Stm -> StateT Variables IO ()
+execute :: Stm -> StateT State IO ()
 execute (SNoop) = return ()
 execute (SExp e) = eval e >> return ()
 execute (SIf b s s') = do
@@ -115,5 +120,8 @@ execute (SDeclD t i) = execute $ SDecl t i $ case t of
        TBool -> EBool False
 execute (SDecl t i e) =do
        v <- eval e
-       (m:ms) <- get
-       put $ (insert i v m):ms
+       state <- get
+       let (m:ms) = variables state in modify (\s -> s{variables=insert i v m:ms })
+
+addFunction :: (MonadState State m) => Func -> m ()
+addFunction (Func _ i d ss) = modify (\s -> s{functions=insert i (d,ss) (functions s) })