Python Ast抽象语法树应该如何使用？

Module(body=[    Print(          dest=None,          values=[BinOp( left=Num(n=1),op=Add(),right=Num(n=2))],          nl=True, )])

func_def = """def add(x, y):    return x + yprint add(3, 5)"""

>>> cm = compile(func_def, '<string>', 'exec')>>> exec cm>>> 8

r_node = ast.parse(func_def)print astunparse.dump(r_node)    # print ast.dump(r_node)

Module(body=[    FunctionDef(        name='add',        args=arguments(            args=[Name(id='x',ctx=Param()),Name(id='y',ctx=Param())],            vararg=None,            kwarg=None,            defaults=[]),        body=[Return(value=BinOp(            left=Name(id='x',ctx=Load()),            op=Add(),            right=Name(id='y',ctx=Load())))],        decorator_list=[]),    Print(        dest=None,        values=[Call(                func=Name(id='add',ctx=Load()),                args=[Num(n=3),Num(n=5)],                keywords=[],                starargs=None,                kwargs=None)],        nl=True)  ])

module Python version "$Revision$"{  mod = Module(stmt* body)| Expression(expr body)  stmt = FunctionDef(identifier name, arguments args, stmt* body, expr* decorator_list)        | ClassDef(identifier name, expr* bases, stmt* body, expr* decorator_list)        | Return(expr? value)        | Print(expr? dest, expr* values, bool nl)| For(expr target, expr iter, stmt* body, stmt* orelse)  expr = BoolOp(boolop op, expr* values)       | BinOp(expr left, operator op, expr right)| Lambda(arguments args, expr body)| Dict(expr* keys, expr* values)| Num(object n) -- a number as a PyObject.       | Str(string s) -- need to specify raw, unicode, etc?| Name(identifier id, expr_context ctx)       | List(expr* elts, expr_context ctx)         -- col_offset is the byte offset in the utf8 string the parser uses        attributes (int lineno, int col_offset)  expr_context = Load | Store | Del | AugLoad | AugStore | Param  boolop = And | Or   operator = Add | Sub | Mult | Div | Mod | Pow | LShift | RShift | BitOr | BitXor | BitAnd | FloorDiv  arguments = (expr* args, identifier? vararg, identifier? kwarg, expr* defaults)}

  class CodeVisitor(ast.NodeVisitor):      def visit_BinOp(self, node):          if isinstance(node.op, ast.Add):              node.op = ast.Sub()          self.generic_visit(node)      def visit_FunctionDef(self, node):          print 'Function Name:%s'% node.name          self.generic_visit(node)          func_log_stmt = ast.Print(              dest = None,              values = [ast.Str(s = 'calling func: %s' % node.name, lineno = 0, col_offset = 0)],              nl = True,              lineno = 0,              col_offset = 0,          )          node.body.insert(0, func_log_stmt)  r_node = ast.parse(func_def)  visitor = CodeVisitor()  visitor.visit(r_node)  # print astunparse.dump(r_node)  print astunparse.unparse(r_node)  exec compile(r_node, '<string>', 'exec')

Function Name:adddef add(x, y):    print 'calling func: add'    return (x - y)print add(3, 5)calling func: add-2

  class CodeTransformer(ast.NodeTransformer):      def visit_BinOp(self, node):          if isinstance(node.op, ast.Add):              node.op = ast.Sub()          self.generic_visit(node)          return node      def visit_FunctionDef(self, node):          self.generic_visit(node)          if node.name == 'add':              node.name = 'sub'          args_num = len(node.args.args)          args = tuple([arg.id for arg in node.args.args])          func_log_stmt = ''.join(["print 'calling func: %s', " % node.name, "'args:'", ", %s" * args_num % args])          node.body.insert(0, ast.parse(func_log_stmt))          return node      def visit_Name(self, node):          replace = {'add': 'sub', 'x': 'a', 'y': 'b'}          re_id = replace.get(node.id, None)          node.id = re_id or node.id          self.generic_visit(node)          return node  r_node = ast.parse(func_def)  transformer = CodeTransformer()  r_node = transformer.visit(r_node)  # print astunparse.dump(r_node)  source = astunparse.unparse(r_node)  print source  # exec compile(r_node, '<string>', 'exec')        # 新加入的node func_log_stmt 缺少lineno和col_offset属性  exec compile(source, '<string>', 'exec')  exec compile(ast.parse(source), '<string>', 'exec')

def sub(a, b):    print 'calling func: sub', 'args:', a, b    return (a - b)print sub(3, 5)calling func: sub args: 3 5-2calling func: sub args: 3 5-2

  class CNCheckHelper(object):      # 待检测文本可能的编码方式列表      VALID_ENCODING = ('utf-8', 'gbk')      def _get_unicode_imp(self, value, idx = 0):          if idx < len(self.VALID_ENCODING):              try:                  return value.decode(self.VALID_ENCODING[idx])              except:                  return self._get_unicode_imp(value, idx + 1)      def _get_unicode(self, from_str):          if isinstance(from_str, unicode):              return None          return self._get_unicode_imp(from_str)      def is_any_chinese(self, check_str, is_strict = True):          unicode_str = self._get_unicode(check_str)          if unicode_str:              c_func = any if is_strict else all              return c_func(u'u4e00' <= char <= u'u9fff' for char in unicode_str)          return False

  class CodeCheck(ast.NodeVisitor):      def __init__(self):          self.cn_checker = CNCheckHelper()      def visit_Str(self, node):          self.generic_visit(node)          # if node.s and any(u'u4e00' <= char <= u'u9fff' for char in node.s.decode('utf-8')):          if self.cn_checker.is_any_chinese(node.s, True):              print 'line no: %d, column offset: %d, CN_Str: %s' % (node.lineno, node.col_offset, node.s)  project_dir = './your_project/script'  for root, dirs, files in os.walk(project_dir):      print root, dirs, files      py_files = filter(lambda file: file.endswith('.py'), files)      checker = CodeCheck()      for file in py_files:          file_path = os.path.join(root, file)          print 'Checking: %s' % file_path          with open(file_path, 'r') as f:              root_node = ast.parse(f.read())              checker.visit(root_node)

  class LambdaCheck(ast.NodeVisitor):      def __init__(self):          self.illegal_args_list = []          self._cur_file = None          self._cur_lambda_args = []      def set_cur_file(self, cur_file):          assert os.path.isfile(cur_file)， cur_file          self._cur_file = os.path.realpath(cur_file)      def visit_Lambda(self, node):          """          lambda 闭包检查原则：          只需检测lambda expr body中args是否引用了lambda args list之外的参数          """          self._cur_lambda_args =[a.id for a in node.args.args]          print astunparse.unparse(node)          # print astunparse.dump(node)          self.get_lambda_body_args(node.body)          self.generic_visit(node)      def record_args(self, name_node):          if isinstance(name_node, ast.Name) and name_node.id not in self._cur_lambda_args:              self.illegal_args_list.append((self._cur_file, 'line no:%s' % name_node.lineno, 'var:%s' % name_node.id))      def _is_args(self, node):          if isinstance(node, ast.Name):              self.record_args(node)              return True          if isinstance(node, ast.Call):              map(self.record_args, node.args)              return True          return False      def get_lambda_body_args(self, node):          if self._is_args(node): return          # for cnode in ast.walk(node):          for cnode in ast.iter_child_nodes(node):              if not self._is_args(cnode):                  self.get_lambda_body_args(cnode)

  project_dir = './your project/script'  for root, dirs, files in os.walk(project_dir):      py_files = filter(lambda file: file.endswith('.py'), files)      checker = LambdaCheck()      for file in py_files:          file_path = os.path.join(root, file)          checker.set_cur_file(file_path)          with open(file_path, 'r') as f:              root_node = ast.parse(f.read())              checker.visit(root_node)      res = '
'.join([' ## '.join(info) for info in checker.illegal_args_list])      print res