added function declarations

app/Compiler.hs

@@ -5,51 +5,9 @@ import Text.Printf (printf)
 import Control.Monad (void) 
 import System.Process
 import System.IO
-
-handleSymbol :: Handle -> ZorthExpr -> IO ()
-
-handleSymbol h (ZorthASTInteger i) = hPutStrLn h $ "    push "<>show i
-
-handleSymbol h (ZorthASTWord "+") = do
-    hPutStr h 
-             "    pop rbx\n\
-             \    pop rax\n\
-             \    add rax, rbx\n\
-             \    push rax\n"
-
-handleSymbol h (ZorthASTWord "-") = do
-    hPutStr h 
-             "    pop rbx\n\
-             \    pop rax\n\
-             \    sub rax, rbx\n\
-             \    push rax\n"
-
-handleSymbol h  (ZorthASTWord "ret") = do
-    hPutStr h 
-             "    mov rax,60\n\
-             \    mov rdi,0\n\
-             \    syscall\n"
-
-handleSymbol h (ZorthASTWord "dup") = do
-    hPutStr h 
-             "    pop rax\n\
-             \    push rax\n\
-             \    push rax\n"
-
-handleSymbol h (ZorthASTWord "swap") = do
-    hPutStr h 
-             "    pop rax\n\
-             \    pop rbx\n\
-             \    push rax\n\
-             \    push rbx\n"
-
-handleSymbol h (ZorthASTWord "drop") = do
-    hPutStr h "    add rsp, 8\n"
-
-handleSymbol h (ZorthASTWord ".") = do
-    hPutStr h 
-              "    pop rbx\n\
-              \    call print_number\n"
+import Control.Monad.Trans.State
+import Control.Monad.IO.Class (liftIO)
+import qualified Data.Map as M
 
 forthPrelude :: Handle -> IO () 
 forthPrelude h = do
@@ -88,8 +46,79 @@ forthPrelude h = do
              \    ret\n\
              \_start:\n"
 
+type Environment = M.Map String ZorthAST
+
+handleSymbol :: Handle -> ZorthExpr -> StateT Environment IO ()
+
+handleSymbol h (ZorthASTInteger i) = 
+    do
+        liftIO $ hPutStrLn h $ "    push "<>show i
+        return ()
+
+handleSymbol h (ZorthASTWord "+") = do
+    liftIO $ hPutStr h 
+             "    pop rbx\n\
+             \    pop rax\n\
+             \    add rax, rbx\n\
+             \    push rax\n"
+    return ()
+
+handleSymbol h (ZorthASTWord "-") = do
+    liftIO $ hPutStr h 
+             "    pop rbx\n\
+             \    pop rax\n\
+             \    sub rax, rbx\n\
+             \    push rax\n"
+    return ()
+
+handleSymbol h  (ZorthASTWord "ret") = do
+    liftIO $ hPutStr h 
+             "    mov rax,60\n\
+             \    mov rdi,0\n\
+             \    syscall\n"
+    return ()
+
+handleSymbol h (ZorthASTWord "dup") = do
+    liftIO $ hPutStr h 
+             "    pop rax\n\
+             \    push rax\n\
+             \    push rax\n"
+    return ()
+
+handleSymbol h (ZorthASTWord "swap") = do
+    liftIO $ hPutStr h 
+             "    pop rax\n\
+             \    pop rbx\n\
+             \    push rax\n\
+             \    push rbx\n"
+    return ()
+
+handleSymbol h (ZorthASTWord "drop") = do
+    liftIO $ hPutStr h "    add rsp, 8\n"
+    return ()
+
+handleSymbol h (ZorthASTWord ".") = do
+    liftIO $ hPutStr h 
+              "    pop rbx\n\
+              \    call print_number\n"
+    return ()
+
+handleSymbol h (ZorthASTWord w) = do
+    state <- get
+    liftIO $ compileZorthAST h (state M.! w) state -- parent env to child and discard
+    return ()
+
+handleSymbol _ (ZorthASTWordDecl (name,ast)) = do
+    state <- get
+    put $ M.insert name ast state
+    return ()
+
+compileZorthAST :: Handle -> ZorthAST -> Environment -> IO ()
+compileZorthAST h ast state = runStateT (foldl (\m x -> m >> handleSymbol h x) (return ()) ast) state >> return ()
+
 compileZorth :: Handle -> ZorthAST -> IO ()
-compileZorth h [] = return ()
+compileZorth _ [] = return ()
 compileZorth h xs = do
     forthPrelude h
-    foldr ((>>) . handleSymbol h) (return ()) xs
+    compileZorthAST h xs M.empty
+