handle symbol reassignment

qlasskit/ast_to_logic.py

@@ -126,6 +126,20 @@ def translate_statement(stmt, env: Env) -> Tuple[List[Tuple[str, BoolExp]], Env]
     """Parse a statement"""
     # match stmt:
     if isinstance(stmt, ast.If):
+        # Translate test expression, body & orelse statements
+        # test = translate_expression(stmt.test, env)
+
+        # body = []
+        # for st_inner in stmt.body:
+        #     exps, env = translate_statement(st_inner, env)
+        #     body.extend(exps)
+
+        # orelse = []
+        # for st_inner in stmt.orelse:
+        #     exps, env = translate_statement(st_inner, env)
+        #     orelse.extend(exps)
+
+        # print(ast.dump(stmt))
         raise exceptions.StatementNotHandledException(stmt)
 
     elif isinstance(stmt, ast.Assign):
@@ -140,6 +154,10 @@ def translate_statement(stmt, env: Env) -> Tuple[List[Tuple[str, BoolExp]], Env]
             )
 
         target = Symbol(stmt.targets[0].id)
+
+        if target in env:
+            raise exceptions.SymbolReassingedException(target)
+
         val = translate_expression(stmt.value, env)
         env[target] = "bool"  # TODO: handle all types
         return [(target, val)], env

qlasskit/exceptions.py

@@ -38,3 +38,8 @@ def __init__(self, message):
 class ConstantReturnException(Exception):
     def __init__(self, name, val):
         super().__init__(f"{name} is costant = {val}")
+
+
+class SymbolReassingedException(Exception):
+    def __init__(self, name):
+        super().__init__(f"{name} cannot be reassinged")

test/test_qlassf_bool.py

@@ -141,3 +141,25 @@ def test_assign3(self):
         qf = qlassf(f, to_compile=False)
         self.assertEqual(len(qf.expressions), 5)
         self.assertEqual(qf.expressions[-1][1], ITE(d & e, g, h))
+
+    def test_reassign_exception(self):
+        f = "def test(a: bool) -> bool:\n\ta = not a\n\treturn a"
+        self.assertRaises(
+            exceptions.SymbolReassingedException,
+            lambda f: qlassf(f, to_compile=False),
+            f,
+        )
+
+    # def test_if(self):
+    #     f = (
+    #         "def test(a: bool, b: bool) -> bool:\n"
+    #         + "\td = False\n"
+    #         + "\tif a:\n"
+    #         + "\t\td = not d\n"
+    #         + "\telse:\n"
+    #         + "\t\td = True\n"
+    #         + "\treturn d"
+    #     )
+    #     qf = qlassf(f, to_compile=False)
+    #     self.assertEqual(len(qf.expressions), 2)
+    #     self.assertEqual(qf.expressions[-1][1], ITE(d & e, g, h))

test/test_qlassf_int.py

@@ -22,6 +22,7 @@ class TestQlassfInt(unittest.TestCase):
     # def test9(a: Int8) -> bool:
     #     return a == 42
 
+    # Raise costant return
     # def test10() -> Int8:
     #     return 42