From b78d4f28adee1d0dab1dd7626650a3c767cd7cb8 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Mon, 12 Sep 2022 08:01:09 +0100
Subject: Some checks

---
 src/Micro/Compiler.hs | 15 +++++++++++----
 src/Micro/Error.hs    |  3 ++-
 test/Language.hs      | 11 ++++++++++-
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/Micro/Compiler.hs b/src/Micro/Compiler.hs
index f305893..89ba802 100644
--- a/src/Micro/Compiler.hs
+++ b/src/Micro/Compiler.hs
@@ -5,6 +5,7 @@ module Micro.Compiler
   )
 where
 
+import Control.Arrow (ArrowChoice (left))
 import Control.Monad.State
 import Data.Maybe (catMaybes, fromMaybe, isNothing)
 import Micro.Asm.Sdcc (generate)
@@ -108,6 +109,9 @@ compileOne x = do
     (A.Module _ _) -> pure Nothing
     (A.Num _ _) -> pure $ Just $ A.Type "u8" -- TODO: placeholder
     (A.Bool' _ _) -> pure $ Just $ A.Type "bool"
+    (A.BinOp _ pos (A.Bool' _ _) (A.Bool' _ _)) ->
+      -- for now this is true
+      addError $ Error InvalidOperation "invalid operation for type bool" pos
     (A.BinOp op pos a b) -> do
       ta <- compileOne a
       tb <- compileOne b
@@ -179,13 +183,16 @@ compileOne x = do
         Just Sym {symType = t} -> pure $ Just t
         Nothing -> addError $ Error Undefined ("undefined \"" ++ ident ++ "\"") pos
 
-foldConstant :: A.Expr -> Either [Error] A.Expr
+foldConstant :: A.Expr -> Either Error A.Expr
 foldConstant x =
   case x of
-    -- FIXME: overflow, invalid, etc
+    -- FIXME: overflow?
     (A.BinOp A.Plus pos (A.Num a _) (A.Num b _)) -> Right $ A.Num (a + b) pos
     (A.BinOp A.Minus pos (A.Num a _) (A.Num b _)) -> Right $ A.Num (a - b) pos
     (A.BinOp A.Mul pos (A.Num a _) (A.Num b _)) -> Right $ A.Num (a * b) pos
+    (A.BinOp A.Mul pos _ (A.Num 0 _)) -> Right $ A.Num 0 pos
+    (A.BinOp A.Mul pos (A.Num 0 _) _) -> Right $ A.Num 0 pos
+    (A.BinOp A.Div pos _ (A.Num 0 _)) -> Left $ Error InvalidOperation "division by zero" pos
     (A.BinOp A.Div pos (A.Num a _) (A.Num b _)) -> Right $ A.Num (a `div` b) pos
     (A.BinOp op pos a b) -> do
       fa <- foldConstant a
@@ -220,10 +227,10 @@ compileAll ast = do
 compileToAst :: [A.Expr] -> Either [Error] [A.Expr]
 compileToAst ast = do
   _ <- evalState (compileAll ast) startState
-  traverse foldConstant ast
+  left (\e -> [e]) $ traverse foldConstant ast
 
 compile :: [A.Expr] -> Either [Error] String
 compile ast = do
   sym <- evalState (compileAll ast) startState
-  fast <- traverse foldConstant ast
+  fast <- left (\e -> [e]) $ traverse foldConstant ast
   return $ generate version sym fast
diff --git a/src/Micro/Error.hs b/src/Micro/Error.hs
index ced1318..e82c0da 100644
--- a/src/Micro/Error.hs
+++ b/src/Micro/Error.hs
@@ -4,7 +4,7 @@ import Data.List (sort)
 import Text.Parsec (SourcePos, errorPos)
 import Text.Parsec.Error (ParseError, errorMessages, showErrorMessages)
 
-data ErrorType = GenericError | TypeError | UnexpectedReturn | AlreadyDefined | NonCallable | Undefined | UndefinedType | InvalidTarget deriving (Show)
+data ErrorType = GenericError | TypeError | UnexpectedReturn | AlreadyDefined | NonCallable | Undefined | UndefinedType | InvalidTarget | InvalidOperation deriving (Show)
 
 instance Enum ErrorType where
   fromEnum GenericError = 0
@@ -15,6 +15,7 @@ instance Enum ErrorType where
   fromEnum Undefined = 5
   fromEnum UndefinedType = 6
   fromEnum InvalidTarget = 7
+  fromEnum InvalidOperation = 8
   toEnum _ = error "toEnum is undefined for Error"
 
 data Error = Error ErrorType String SourcePos
diff --git a/test/Language.hs b/test/Language.hs
index 6e15525..84c10b4 100644
--- a/test/Language.hs
+++ b/test/Language.hs
@@ -416,6 +416,14 @@ testCaseE17 =
         \1 + false;\n"
         E.TypeError
 
+testCaseE18 =
+  TestLabel "div by 0" $
+    TestCase $
+      expectError
+        "module main\n\
+        \1 / 0;\n"
+        E.InvalidOperation
+
 language =
   [ testCase2,
     testCase3,
@@ -452,5 +460,6 @@ language =
     testCaseE14,
     testCaseE15,
     testCaseE16,
-    testCaseE17
+    testCaseE17,
+    testCaseE18
   ]
-- 
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