rust/crates/ra_syntax/src/ast/edit.rs

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//! This module contains functions for editing syntax trees. As the trees are
//! immutable, all function here return a fresh copy of the tree, instead of
//! doing an in-place modification.
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use std::{iter, ops::RangeInclusive};
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use arrayvec::ArrayVec;
use crate::{
algo,
ast::{
self,
make::{self, tokens},
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AstNode, TypeBoundsOwner,
},
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AstToken, Direction, InsertPosition, SmolStr, SyntaxElement,
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SyntaxKind::{ATTR, COMMENT, WHITESPACE},
SyntaxNode, T,
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};
impl ast::FnDef {
#[must_use]
pub fn with_body(&self, body: ast::Block) -> ast::FnDef {
let mut to_insert: ArrayVec<[SyntaxElement; 2]> = ArrayVec::new();
let old_body_or_semi: SyntaxElement = if let Some(old_body) = self.body() {
old_body.syntax().clone().into()
} else if let Some(semi) = self.semicolon_token() {
to_insert.push(make::tokens::single_space().into());
semi.into()
} else {
to_insert.push(make::tokens::single_space().into());
to_insert.push(body.syntax().clone().into());
return insert_children(self, InsertPosition::Last, to_insert.into_iter());
};
to_insert.push(body.syntax().clone().into());
let replace_range = RangeInclusive::new(old_body_or_semi.clone(), old_body_or_semi);
replace_children(self, replace_range, to_insert.into_iter())
}
}
impl ast::ItemList {
#[must_use]
pub fn append_items(&self, items: impl Iterator<Item = ast::ImplItem>) -> ast::ItemList {
let mut res = self.clone();
if !self.syntax().text().contains_char('\n') {
res = res.make_multiline();
}
items.for_each(|it| res = res.append_item(it));
res
}
#[must_use]
pub fn append_item(&self, item: ast::ImplItem) -> ast::ItemList {
let (indent, position) = match self.impl_items().last() {
Some(it) => (
leading_indent(it.syntax()).unwrap_or_default().to_string(),
InsertPosition::After(it.syntax().clone().into()),
),
None => match self.l_curly() {
Some(it) => (
" ".to_string() + &leading_indent(self.syntax()).unwrap_or_default(),
InsertPosition::After(it),
),
None => return self.clone(),
},
};
let ws = tokens::WsBuilder::new(&format!("\n{}", indent));
let to_insert: ArrayVec<[SyntaxElement; 2]> =
[ws.ws().into(), item.syntax().clone().into()].into();
insert_children(self, position, to_insert.into_iter())
}
fn l_curly(&self) -> Option<SyntaxElement> {
self.syntax().children_with_tokens().find(|it| it.kind() == T!['{'])
}
fn make_multiline(&self) -> ast::ItemList {
let l_curly = match self.syntax().children_with_tokens().find(|it| it.kind() == T!['{']) {
Some(it) => it,
None => return self.clone(),
};
let sibling = match l_curly.next_sibling_or_token() {
Some(it) => it,
None => return self.clone(),
};
let existing_ws = match sibling.as_token() {
None => None,
Some(tok) if tok.kind() != WHITESPACE => None,
Some(ws) => {
if ws.text().contains('\n') {
return self.clone();
}
Some(ws.clone())
}
};
let indent = leading_indent(self.syntax()).unwrap_or("".into());
let ws = tokens::WsBuilder::new(&format!("\n{}", indent));
let to_insert = iter::once(ws.ws().into());
match existing_ws {
None => insert_children(self, InsertPosition::After(l_curly), to_insert),
Some(ws) => {
replace_children(self, RangeInclusive::new(ws.clone().into(), ws.into()), to_insert)
}
}
}
}
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impl ast::RecordFieldList {
#[must_use]
pub fn append_field(&self, field: &ast::RecordField) -> ast::RecordFieldList {
self.insert_field(InsertPosition::Last, field)
}
#[must_use]
pub fn insert_field(
&self,
position: InsertPosition<&'_ ast::RecordField>,
field: &ast::RecordField,
) -> ast::RecordFieldList {
let is_multiline = self.syntax().text().contains_char('\n');
let ws;
let space = if is_multiline {
ws = tokens::WsBuilder::new(&format!(
"\n{} ",
leading_indent(self.syntax()).unwrap_or("".into())
));
ws.ws()
} else {
tokens::single_space()
};
let mut to_insert: ArrayVec<[SyntaxElement; 4]> = ArrayVec::new();
to_insert.push(space.into());
to_insert.push(field.syntax().clone().into());
to_insert.push(tokens::comma().into());
macro_rules! after_l_curly {
() => {{
let anchor = match self.l_curly() {
Some(it) => it,
None => return self.clone(),
};
InsertPosition::After(anchor)
}};
}
macro_rules! after_field {
($anchor:expr) => {
if let Some(comma) = $anchor
.syntax()
.siblings_with_tokens(Direction::Next)
.find(|it| it.kind() == T![,])
{
InsertPosition::After(comma)
} else {
to_insert.insert(0, tokens::comma().into());
InsertPosition::After($anchor.syntax().clone().into())
}
};
};
let position = match position {
InsertPosition::First => after_l_curly!(),
InsertPosition::Last => {
if !is_multiline {
// don't insert comma before curly
to_insert.pop();
}
match self.fields().last() {
Some(it) => after_field!(it),
None => after_l_curly!(),
}
}
InsertPosition::Before(anchor) => {
InsertPosition::Before(anchor.syntax().clone().into())
}
InsertPosition::After(anchor) => after_field!(anchor),
};
insert_children(self, position, to_insert.iter().cloned())
}
fn l_curly(&self) -> Option<SyntaxElement> {
self.syntax().children_with_tokens().find(|it| it.kind() == T!['{'])
}
}
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impl ast::TypeParam {
pub fn remove_bounds(&self) -> ast::TypeParam {
let colon = match self.colon_token() {
Some(it) => it,
None => return self.clone(),
};
let end = match self.type_bound_list() {
Some(it) => it.syntax().clone().into(),
None => colon.clone().into(),
};
replace_children(self, RangeInclusive::new(colon.into(), end), iter::empty())
}
}
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pub fn strip_attrs_and_docs<N: ast::AttrsOwner>(node: N) -> N {
N::cast(strip_attrs_and_docs_inner(node.syntax().clone())).unwrap()
}
fn strip_attrs_and_docs_inner(mut node: SyntaxNode) -> SyntaxNode {
while let Some(start) =
node.children_with_tokens().find(|it| it.kind() == ATTR || it.kind() == COMMENT)
{
let end = match &start.next_sibling_or_token() {
Some(el) if el.kind() == WHITESPACE => el.clone(),
Some(_) | None => start.clone(),
};
node = algo::replace_children(&node, RangeInclusive::new(start, end), &mut iter::empty());
}
node
}
// Note this is copy-pasted from fmt. It seems like fmt should be a separate
// crate, but basic tree building should be this crate. However, tree building
// might want to call into fmt...
fn leading_indent(node: &SyntaxNode) -> Option<SmolStr> {
let prev_tokens = std::iter::successors(node.first_token(), |token| token.prev_token());
for token in prev_tokens {
if let Some(ws) = ast::Whitespace::cast(token.clone()) {
let ws_text = ws.text();
if let Some(pos) = ws_text.rfind('\n') {
return Some(ws_text[pos + 1..].into());
}
}
if token.text().contains('\n') {
break;
}
}
None
}
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#[must_use]
fn insert_children<N: AstNode>(
parent: &N,
position: InsertPosition<SyntaxElement>,
mut to_insert: impl Iterator<Item = SyntaxElement>,
) -> N {
let new_syntax = algo::insert_children(parent.syntax(), position, &mut to_insert);
N::cast(new_syntax).unwrap()
}
#[must_use]
fn replace_children<N: AstNode>(
parent: &N,
to_replace: RangeInclusive<SyntaxElement>,
mut to_insert: impl Iterator<Item = SyntaxElement>,
) -> N {
let new_syntax = algo::replace_children(parent.syntax(), to_replace, &mut to_insert);
N::cast(new_syntax).unwrap()
}