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|
use {Node, NodeType, TextUnit, TextRange};
use ::visitor::{visitor, process_subtree_bottom_up};
pub fn child_of_type(node: Node, ty: NodeType) -> Option<Node> {
node.children().find(|n| n.ty() == ty)
}
pub fn children_of_type<'f>(node: Node<'f>, ty: NodeType) -> Box<Iterator<Item=Node<'f>> + 'f> {
Box::new(node.children().filter(move |n| n.ty() == ty))
}
pub fn subtree<'f>(node: Node<'f>) -> Box<Iterator<Item=Node<'f>> + 'f> {
Box::new(node.children().flat_map(subtree).chain(::std::iter::once(node)))
}
pub fn descendants_of_type<'f>(node: Node<'f>, ty: NodeType) -> Vec<Node<'f>> {
process_subtree_bottom_up(
node,
visitor(Vec::new())
.visit_nodes(&[ty], |node, nodes| nodes.push(node))
)
}
pub fn child_of_type_exn(node: Node, ty: NodeType) -> Node {
child_of_type(node, ty).unwrap_or_else(|| {
panic!("No child of type {:?} for {:?}\
----\
{}\
----", ty, node.ty(), node.text())
})
}
pub fn ancestors(node: Node) -> Ancestors {
Ancestors(Some(node))
}
pub struct Ancestors<'f>(Option<Node<'f>>);
impl<'f> Iterator for Ancestors<'f> {
type Item = Node<'f>;
fn next(&mut self) -> Option<Self::Item> {
let current = self.0;
self.0 = current.and_then(|n| n.parent());
current
}
}
pub fn is_leaf(node: Node) -> bool {
node.children().next().is_none() && !node.range().is_empty()
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
pub enum Direction {
Left, Right
}
pub fn sibling(node: Node, dir: Direction) -> Option<Node> {
let (parent, idx) = child_position(node)?;
let idx = match dir {
Direction::Left => idx.checked_sub(1)?,
Direction::Right => idx + 1,
};
parent.children().nth(idx)
}
pub mod ast {
use {Node, AstNode, TextUnit, AstChildren};
use visitor::{visitor, process_subtree_bottom_up};
use super::{ancestors, find_leaf_at_offset, LeafAtOffset};
pub fn ancestor<'f, T: AstNode<'f>>(node: Node<'f>) -> Option<T> {
ancestors(node)
.filter_map(T::wrap)
.next()
}
pub fn ancestor_exn<'f, T: AstNode<'f>>(node: Node<'f>) -> T {
ancestor(node).unwrap()
}
pub fn children_of_type<'f, N: AstNode<'f>>(node: Node<'f>) -> AstChildren<N> {
AstChildren::new(node.children())
}
pub fn descendants_of_type<'f, N: AstNode<'f>>(node: Node<'f>) -> Vec<N> {
process_subtree_bottom_up(
node,
visitor(Vec::new())
.visit::<N, _>(|node, acc| acc.push(node))
)
}
pub fn node_at_offset<'f, T: AstNode<'f>>(node: Node<'f>, offset: TextUnit) -> Option<T> {
match find_leaf_at_offset(node, offset) {
LeafAtOffset::None => None,
LeafAtOffset::Single(node) => ancestor(node),
LeafAtOffset::Between(left, right) => ancestor(left).or_else(|| ancestor(right)),
}
}
}
pub mod traversal {
use {Node};
pub fn bottom_up<'f, F: FnMut(Node<'f>)>(node: Node<'f>, mut f: F)
{
go(node, &mut f);
fn go<'f, F: FnMut(Node<'f>)>(node: Node<'f>, f: &mut F) {
for child in node.children() {
go(child, f)
}
f(node);
}
}
}
fn child_position(child: Node) -> Option<(Node, usize)> {
child.parent()
.map(|parent| {
(parent, parent.children().position(|n| n == child).unwrap())
})
}
fn common_ancestor<'f>(n1: Node<'f>, n2: Node<'f>) -> Node<'f> {
for p in ancestors(n1) {
if ancestors(n2).any(|a| a == p) {
return p;
}
}
panic!("Can't find common ancestor of {:?} and {:?}", n1, n2)
}
|
