+ g (VarExpr _ (VarDef k fs)) = load k >>= \instr-> tell [instr] //note: pure is pure for list, i.e. []
+ g (IntExpr _ i) = loadP (LDC i) >>= \instr-> tell [instr]
+ g (CharExpr _ c) = abort "How to deal with chars?"
+ g (BoolExpr _ True) = loadP (LDC TRUE) >>= \instr-> tell [instr]
+ g (BoolExpr _ False) = loadP (LDC FALSE) >>= \instr-> tell [instr]
+ g (Op2Expr _ e1 op e2) = g e1 >>| g e2 >>| tell [Instr (op2ins op) [] ""]
+ g (Op1Expr _ UnNegation e) = g e >>| tell [Instr "not" [] ""]
+ g (Op1Expr _ UnMinus e) = g e >>| tell [Instr "neg" [] ""]
+ g (EmptyListExpr _) = abort "Shit, empty list expr"
+ g (TupleExpr p (e1,e2)) = abort "How to deal with tuples?"
+ g (FunExpr _ k es fs) =
+ mapM g es >>| //put all arguments on the stack (todo: fix argument handling!)
+ jump "bsr" k >>= \instr->
+ tell [instr] >>| //actually branch to function
+ tell [Instr "ldr" [Raw "RR"] ""] //push return value on stack, todo: check for VOID
+
+instance g Stmt where
+ g (IfStmt cond th el) =
+ fresh >>= \elseLabel->
+ fresh >>= \endLabel->
+ g cond >>|
+ tell [Instr "brf" [L elseLabel] "branch else"] >>|
+ mapM_ g th >>|
+ tell [Instr "bra" [L endLabel] "branch end if"] >>|
+ tell [Lab elseLabel] >>|
+ mapM_ g el >>|
+ tell [Lab endLabel]
+ g (WhileStmt cond th) =
+ fresh >>= \startLabel->
+ fresh >>= \endLabel ->
+ tell [Lab startLabel] >>|
+ g cond >>|
+ tell [Instr "brf" [L endLabel] "branch end while"] >>|
+ mapM_ g th >>|
+ tell [Instr "bra" [L startLabel] "branch start while"] >>|
+ tell [Lab endLabel]
+ g (AssStmt (VarDef k fs) e) =
+ g e >>|
+ abort "Shit, an assignment, figure out something with storing vars or something"
+ //vars will be on stack in locals (possible pointers to heap)
+ g (FunStmt _ _) = abort "CodeGen, FunStmt unused" //not used
+ g (ReturnStmt Nothing) = tell [Instr "ret" [] ""] //NOTE! Assumes only return address on stack, safe?
+ g (ReturnStmt (Just e)) =
+ g e >>|
+ tell [Instr "str" [Raw "RR"] ""] >>|
+ g (ReturnStmt Nothing)
+
+instance g VarDecl where
+ g (VarDecl _ Nothing _ _) = liftT (Left $ Error "PANIC: untyped vardecl")
+ g (VarDecl _ (Just t) k e) =
+ (\l->k+++"_"+++l) <$> fresh >>= \lbl->
+ changeGenMap (extend k (FUNC lbl)) >>|
+ tell [Lab lbl] >>|
+ g e >>|
+ tell [Instr "str" [Raw "RR"] ""] >>|
+ tell [Instr "ret" [] ""]
+
+
+instance g FunDecl where
+ g (FunDecl _ k _ _ vds stms) =
+ //varDecls can call the enclosing function, so first reserve a label for it
+ (\l-> if (k=="main") "main" (l+++"_"+++k)) <$> fresh >>= \lbl->
+ changeGenMap (extend k (FUNC lbl)) >>|
+ //then generate functions for the VarDecls
+ genMap >>= \oldMap ->
+ mapM_ g vds >>|
+ //then the main function
+ tell [Lab lbl] >>|
+ mapM_ g stms >>|
+ changeGenMap (const oldMap) >>| pure ()
+
+op2ins :: Op2 -> String
+op2ins op = case op of
+ BiPlus = "add"
+ BiMinus = "sub"
+ BiTimes = "mul"
+ BiDivide = "div"
+ BiMod = "mod"
+ BiEquals = "eq"
+ BiLesser = "lt"
+ BiGreater = "gt"
+ BiLesserEq = "le"
+ BiGreaterEq = "ge"
+ BiUnEqual = "ne"
+ BiAnd = "and"
+ BiOr = "or"
+ BiCons = abort "Shit, Cons, how to deal with this?"