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