@dataclass class DebugVisitor(Visitor[T]): tree_depth: int = 0 def visit_default(self, node: LN) -> Iterator[T]: indent = ' ' * (2 * self.tree_depth) if isinstance(node, Node): _type = type_repr(node.type) out(f'{indent}{_type}', fg='yellow') self.tree_depth += 1 for child in node.children: yield from self.visit(child) self.tree_depth -= 1 out(f'{indent}/{_type}', fg='yellow', bold=False) else: _type = token.tok_name.get(node.type, str(node.type)) out(f'{indent}{_type}', fg='blue', nl=False) if node.prefix: # We don't have to handle prefixes for `Node` objects since # that delegates to the first child anyway. out(f' {node.prefix!r}', fg='green', bold=False, nl=False) out(f' {node.value!r}', fg='blue', bold=False) @classmethod def show(cls, code: str) -> None: """Pretty-prints a given string of `code`. Convenience method for debugging. """ v: DebugVisitor[None] = DebugVisitor() list(v.visit(lib2to3_parse(code)))