Add support for for loops in python interpreter (#24429)

Add support for for loops

src/transformers/tools/agents.py

@@ -48,6 +48,7 @@ _tools_are_initialized = False
 
 BASE_PYTHON_TOOLS = {
     "print": print,
+    "range": range,
     "float": float,
     "int": int,
     "bool": bool,

src/transformers/tools/python_interpreter.py

@@ -110,6 +110,9 @@ def evaluate_ast(expression: ast.AST, state: Dict[str, Any], tools: Dict[str, Ca
     elif isinstance(expression, ast.Expr):
         # Expression -> evaluate the content
         return evaluate_ast(expression.value, state, tools)
+    elif isinstance(expression, ast.For):
+        # For loop -> execute the loop
+        return evaluate_for(expression, state, tools)
     elif isinstance(expression, ast.FormattedValue):
         # Formatted value (part of f-string) -> evaluate the content and return
         return evaluate_ast(expression.value, state, tools)
@@ -236,3 +239,15 @@ def evaluate_if(if_statement, state, tools):
             if line_result is not None:
                 result = line_result
     return result
+
+
+def evaluate_for(for_loop, state, tools):
+    result = None
+    iterator = evaluate_ast(for_loop.iter, state, tools)
+    for counter in iterator:
+        state[for_loop.target.id] = counter
+        for expression in for_loop.body:
+            line_result = evaluate_ast(expression, state, tools)
+            if line_result is not None:
+                result = line_result
+    return result

tests/tools/test_python_interpreter.py

@@ -122,3 +122,10 @@ class PythonInterpreterTester(unittest.TestCase):
         result = evaluate(code, {"add_two": add_two}, state=state)
         assert result == 5
         self.assertDictEqual(state, {"x": 3, "test_dict": {"x": 3, "y": 5}})
+
+    def test_evaluate_for(self):
+        code = "x = 0\nfor i in range(3):\n    x = i"
+        state = {}
+        result = evaluate(code, {"range": range}, state=state)
+        assert result == 2
+        self.assertDictEqual(state, {"x": 2, "i": 2})