Filename: //lib//python3//dist-packages//jinja2/visitor.py

# -*- coding: utf-8 -*- """API for traversing the AST nodes. Implemented by the compiler and meta introspection. """ from .nodes import Node class NodeVisitor(object): """Walks the abstract syntax tree and call visitor functions for every node found. The visitor functions may return values which will be forwarded by the `visit` method. Per default the visitor functions for the nodes are ``'visit_'`` + class name of the node. So a `TryFinally` node visit function would be `visit_TryFinally`. This behavior can be changed by overriding the `get_visitor` function. If no visitor function exists for a node (return value `None`) the `generic_visit` visitor is used instead. """ def get_visitor(self, node): """Return the visitor function for this node or `None` if no visitor exists for this node. In that case the generic visit function is used instead. """ method = "visit_" + node.__class__.__name__ return getattr(self, method, None) def visit(self, node, *args, **kwargs): """Visit a node.""" f = self.get_visitor(node) if f is not None: return f(node, *args, **kwargs) return self.generic_visit(node, *args, **kwargs) def generic_visit(self, node, *args, **kwargs): """Called if no explicit visitor function exists for a node.""" for node in node.iter_child_nodes(): self.visit(node, *args, **kwargs) class NodeTransformer(NodeVisitor): """Walks the abstract syntax tree and allows modifications of nodes. The `NodeTransformer` will walk the AST and use the return value of the visitor functions to replace or remove the old node. If the return value of the visitor function is `None` the node will be removed from the previous location otherwise it's replaced with the return value. The return value may be the original node in which case no replacement takes place. """ def generic_visit(self, node, *args, **kwargs): for field, old_value in node.iter_fields(): if isinstance(old_value, list): new_values = [] for value in old_value: if isinstance(value, Node): value = self.visit(value, *args, **kwargs) if value is None: continue elif not isinstance(value, Node): new_values.extend(value) continue new_values.append(value) old_value[:] = new_values elif isinstance(old_value, Node): new_node = self.visit(old_value, *args, **kwargs) if new_node is None: delattr(node, field) else: setattr(node, field, new_node) return node def visit_list(self, node, *args, **kwargs): """As transformers may return lists in some places this method can be used to enforce a list as return value. """ rv = self.visit(node, *args, **kwargs) if not isinstance(rv, list): rv = [rv] return rv

./Ninja\.