53 lines
1.8 KiB
Rust
53 lines
1.8 KiB
Rust
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//! This module contains functions for editing syntax trees. As the trees are
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//! immutable, all function here return a fresh copy of the tree, instead of
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//! doing an in-place modification.
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use arrayvec::ArrayVec;
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use std::ops::RangeInclusive;
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use crate::{
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algo,
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ast::{self, make, AstNode},
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InsertPosition, SyntaxElement,
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};
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impl ast::FnDef {
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#[must_use]
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pub fn with_body(&self, body: ast::Block) -> ast::FnDef {
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let mut to_insert: ArrayVec<[SyntaxElement; 2]> = ArrayVec::new();
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let old_body_or_semi: SyntaxElement = if let Some(old_body) = self.body() {
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old_body.syntax().clone().into()
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} else if let Some(semi) = self.semicolon_token() {
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to_insert.push(make::tokens::single_space().into());
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semi.into()
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} else {
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to_insert.push(make::tokens::single_space().into());
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to_insert.push(body.syntax().clone().into());
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return insert_children(self, InsertPosition::Last, to_insert.into_iter());
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};
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to_insert.push(body.syntax().clone().into());
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let replace_range = RangeInclusive::new(old_body_or_semi.clone(), old_body_or_semi);
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replace_children(self, replace_range, to_insert.into_iter())
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}
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}
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#[must_use]
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fn insert_children<N: AstNode>(
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parent: &N,
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position: InsertPosition<SyntaxElement>,
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mut to_insert: impl Iterator<Item = SyntaxElement>,
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) -> N {
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let new_syntax = algo::insert_children(parent.syntax(), position, &mut to_insert);
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N::cast(new_syntax).unwrap()
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}
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#[must_use]
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fn replace_children<N: AstNode>(
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parent: &N,
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to_replace: RangeInclusive<SyntaxElement>,
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mut to_insert: impl Iterator<Item = SyntaxElement>,
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) -> N {
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let new_syntax = algo::replace_children(parent.syntax(), to_replace, &mut to_insert);
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N::cast(new_syntax).unwrap()
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}
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