Template for visiting all Python AST nodes

ast_visitor_template.py

"""
All the methods were generated based on the list of nodes from the
"Green Tree Snakes" guide:
https://greentreesnakes.readthedocs.io/en/latest/index.html
"""

import ast


class Visitor(ast.NodeVisitor):

    def visit_Num(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Str(self, node):
        print(node)
        self.generic_visit(node)

    def visit_FormattedValue(self, node):
        print(node)
        self.generic_visit(node)

    def visit_JoinedStr(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Bytes(self, node):
        print(node)
        self.generic_visit(node)

    def visit_List(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Tuple(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Set(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Dict(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Ellipsis(self, node):
        print(node)
        self.generic_visit(node)

    def visit_NameConstant(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Name(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Load(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Store(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Del(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Starred(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Expr(self, node):
        print(node)
        self.generic_visit(node)

    def visit_UnaryOp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_UAdd(self, node):
        print(node)
        self.generic_visit(node)

    def visit_USub(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Not(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Invert(self, node):
        print(node)
        self.generic_visit(node)

    def visit_BinOp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Add(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Sub(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Mult(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Div(self, node):
        print(node)
        self.generic_visit(node)

    def visit_FloorDiv(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Mod(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Pow(self, node):
        print(node)
        self.generic_visit(node)

    def visit_LShift(self, node):
        print(node)
        self.generic_visit(node)

    def visit_RShift(self, node):
        print(node)
        self.generic_visit(node)

    def visit_BitOr(self, node):
        print(node)
        self.generic_visit(node)

    def visit_BitXor(self, node):
        print(node)
        self.generic_visit(node)

    def visit_BitAnd(self, node):
        print(node)
        self.generic_visit(node)

    def visit_MatMult(self, node):
        print(node)
        self.generic_visit(node)

    def visit_BoolOp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_And(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Or(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Compare(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Eq(self, node):
        print(node)
        self.generic_visit(node)

    def visit_NotEq(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Lt(self, node):
        print(node)
        self.generic_visit(node)

    def visit_LtE(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Gt(self, node):
        print(node)
        self.generic_visit(node)

    def visit_GtE(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Is(self, node):
        print(node)
        self.generic_visit(node)

    def visit_IsNot(self, node):
        print(node)
        self.generic_visit(node)

    def visit_In(self, node):
        print(node)
        self.generic_visit(node)

    def visit_NotIn(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Call(self, node):
        print(node)
        self.generic_visit(node)

    def visit_keyword(self, node):
        print(node)
        self.generic_visit(node)

    def visit_IfExp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Attribute(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Subscript(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Index(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Slice(self, node):
        print(node)
        self.generic_visit(node)

    def visit_ExtSlice(self, node):
        print(node)
        self.generic_visit(node)

    def visit_ListComp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_SetComp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_GeneratorExp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_DictComp(self, node):
        print(node)
        self.generic_visit(node)

    def visit_comprehension(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Assign(self, node):
        print(node)
        self.generic_visit(node)

    def visit_AnnAssign(self, node):
        print(node)
        self.generic_visit(node)

    def visit_AugAssign(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Print(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Raise(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Assert(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Delete(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Pass(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Import(self, node):
        print(node)
        self.generic_visit(node)

    def visit_ImportFrom(self, node):
        print(node)
        self.generic_visit(node)

    def visit_alias(self, node):
        print(node)
        self.generic_visit(node)

    def visit_If(self, node):
        print(node)
        self.generic_visit(node)

    def visit_For(self, node):
        print(node)
        self.generic_visit(node)

    def visit_While(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Break(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Continue(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Try(self, node):
        print(node)
        self.generic_visit(node)

    def visit_TryFinally(self, node):
        print(node)
        self.generic_visit(node)

    def visit_TryExcept(self, node):
        print(node)
        self.generic_visit(node)

    def visit_ExceptHandler(self, node):
        print(node)
        self.generic_visit(node)

    def visit_With(self, node):
        print(node)
        self.generic_visit(node)

    def visit_withitem(self, node):
        print(node)
        self.generic_visit(node)

    def visit_FunctionDef(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Lambda(self, node):
        print(node)
        self.generic_visit(node)

    def visit_arguments(self, node):
        print(node)
        self.generic_visit(node)

    def visit_arg(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Return(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Yield(self, node):
        print(node)
        self.generic_visit(node)

    def visit_YieldFrom(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Global(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Nonlocal(self, node):
        print(node)
        self.generic_visit(node)

    def visit_ClassDef(self, node):
        print(node)
        self.generic_visit(node)

    def visit_AsyncFunctionDef(self, node):
        print(node)
        self.generic_visit(node)

    def visit_Await(self, node):
        print(node)
        self.generic_visit(node)

    def visit_AsyncFor(self, node):
        print(node)
        self.generic_visit(node)

    def visit_AsyncWith(self, node):
        print(node)
        self.generic_visit(node)


SOURCE = """
def hello(msg):
    a = 21 * 2
    print(msg, a)
"""

if __name__ == "__main__":
    root = ast.parse(SOURCE)
    visitor = Visitor()
    visitor.visit(root)

def visit_Module(self, node):
    print(node)
    self.generic_visit(node)

Module visit missing from template.

For me visit_str didn't work; visit_const worked for me instead.
(I might be confusing this with something else, because I inherited form pylint.checkers.BaseChecker, which does seem to use astroid, but isn't a subclass of NodeVisitor)

What if we use Python itself for listing the available Python AST nodes:

import ast
import enum
import inspect

def allnodes():
    # Deprecated nodes are listed here:
    # https://docs.python.org/3/library/ast.html
    deprecated = ['Num', 'Str', 'Bytes', 'NameConstant', 'Ellipsis', 'Index', 'ExtSlice']
    ignore = ['AST']
    for name in dir(ast):
        attr = getattr(ast, name)
        if not inspect.isclass(attr):
            continue
        if issubclass(attr, enum.Enum):
            continue
        if not issubclass(attr, ast.AST):
            continue
        if name in deprecated + ignore:
            continue
        yield name

METHOD = '''
    def visit_%s(self, node):
        print(node)
        self.generic_visit(node)
        return node
'''

def genvisitor(name):
    nodes = allnodes()
    code = ['class %s(ast.NodeVisitor):' % name]
    for node in nodes:
        code.append(METHOD % node)
    return ''.join(code)

print(genvisitor('MyVisitor'))

This yields the following:

class MyVisitor(ast.NodeVisitor):
    def visit_Add(self, node):
        print(node)
        self.generic_visit(node)
        return node

    def visit_And(self, node):
        print(node)
        self.generic_visit(node)
        return node
    ...

Very happy to find this list, thanks!

Just a note to others who may find: when following along with the pylint docs demo which uses the BaseChecker class, use lowercase visit_x