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pub mod visit;
use rowan::TransparentNewType;
use crate::{SyntaxNode, TextRange, TextUnit, AstNode};
pub use rowan::LeafAtOffset;
pub fn find_leaf_at_offset(node: &SyntaxNode, offset: TextUnit) -> LeafAtOffset<&SyntaxNode> {
match node.0.leaf_at_offset(offset) {
LeafAtOffset::None => LeafAtOffset::None,
LeafAtOffset::Single(n) => LeafAtOffset::Single(SyntaxNode::from_repr(n)),
LeafAtOffset::Between(l, r) => {
LeafAtOffset::Between(SyntaxNode::from_repr(l), SyntaxNode::from_repr(r))
}
}
}
/// Finds a node of specific Ast type at offset. Note that this is slightly
/// imprecise: if the cursor is strictly between two nodes of the desired type,
/// as in
///
/// ```no-run
/// struct Foo {}|struct Bar;
/// ```
///
/// then the left node will be silently preferred.
pub fn find_node_at_offset<N: AstNode>(syntax: &SyntaxNode, offset: TextUnit) -> Option<&N> {
find_leaf_at_offset(syntax, offset).find_map(|leaf| leaf.ancestors().find_map(N::cast))
}
pub fn find_covering_node(root: &SyntaxNode, range: TextRange) -> &SyntaxNode {
SyntaxNode::from_repr(root.0.covering_node(range))
}
pub fn generate<T>(seed: Option<T>, step: impl Fn(&T) -> Option<T>) -> impl Iterator<Item = T> {
::itertools::unfold(seed, move |slot| {
slot.take().map(|curr| {
*slot = step(&curr);
curr
})
})
}
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