stmt_inferrer.py 文件源码

 复制代码def _infer_for(node, context, solver):
    """Infer the type for a for loop node

    Limitation:
        - The iterable can't be a tuple.
            For example: the following is not allowed:
                for x in (1, 2.0, "string"):
                    ....
    """
    iter_type = expr.infer(node.iter, context, solver)

    # Infer the target in the loop, inside the global context
    # Cases:
    # - Var name. Ex: for i in range(5)..
    # - Tuple. Ex: for (a,b) in [(1,"st"), (3,"st2")]..
    # - List. Ex: for [a,b] in [(1, "st"), (3, "st2")]..
    target_type = solver.new_z3_const("for_target")
    solver.add(axioms.for_loop(iter_type, target_type, solver.z3_types),
               fail_message="For loop in line {}".format(node.lineno))

    _infer_assignment_target(node.target, context, target_type, solver)

    return _infer_control_flow(node, context, solver)