rust/crates/ra_syntax/src/ast/edit.rs
2020-04-09 22:22:58 +02:00

588 lines
19 KiB
Rust

//! 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.
use std::{iter, ops::RangeInclusive};
use arrayvec::ArrayVec;
use crate::{
algo::{self, neighbor, SyntaxRewriter},
ast::{
self,
make::{self, tokens},
AstNode, TypeBoundsOwner,
},
AstToken, Direction, InsertPosition, SmolStr, SyntaxElement, SyntaxKind,
SyntaxKind::{ATTR, COMMENT, WHITESPACE},
SyntaxNode, SyntaxToken, T,
};
impl ast::BinExpr {
#[must_use]
pub fn replace_op(&self, op: SyntaxKind) -> Option<ast::BinExpr> {
let op_node: SyntaxElement = self.op_details()?.0.into();
let to_insert: Option<SyntaxElement> = Some(make::token(op).into());
Some(self.replace_children(single_node(op_node), to_insert))
}
}
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.semi_token() {
to_insert.push(make::tokens::single_space().into());
semi.syntax.clone().into()
} else {
to_insert.push(make::tokens::single_space().into());
to_insert.push(body.syntax().clone().into());
return self.insert_children(InsertPosition::Last, to_insert);
};
to_insert.push(body.syntax().clone().into());
self.replace_children(single_node(old_body_or_semi), to_insert)
}
}
fn make_multiline<N>(node: N) -> N
where
N: AstNode + Clone,
{
let l_curly = match node.syntax().children_with_tokens().find(|it| it.kind() == T!['{']) {
Some(it) => it,
None => return node,
};
let sibling = match l_curly.next_sibling_or_token() {
Some(it) => it,
None => return node,
};
let existing_ws = match sibling.as_token() {
None => None,
Some(tok) if tok.kind() != WHITESPACE => None,
Some(ws) => {
if ws.text().contains('\n') {
return node;
}
Some(ws.clone())
}
};
let indent = leading_indent(node.syntax()).unwrap_or_default();
let ws = tokens::WsBuilder::new(&format!("\n{}", indent));
let to_insert = iter::once(ws.ws().into());
match existing_ws {
None => node.insert_children(InsertPosition::After(l_curly), to_insert),
Some(ws) => node.replace_children(single_node(ws), to_insert),
}
}
impl ast::ItemList {
#[must_use]
pub fn append_items(&self, items: impl IntoIterator<Item = ast::ImplItem>) -> ast::ItemList {
let mut res = self.clone();
if !self.syntax().text().contains_char('\n') {
res = make_multiline(res);
}
items.into_iter().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_token() {
Some(it) => (
" ".to_string() + &leading_indent(self.syntax()).unwrap_or_default(),
InsertPosition::After(it.syntax().clone().into()),
),
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();
self.insert_children(position, to_insert)
}
}
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_default()
));
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(make::token(T![,]).into());
macro_rules! after_l_curly {
() => {{
let anchor = match self.l_curly_token() {
Some(it) => it.syntax().clone().into(),
None => return self.clone(),
};
InsertPosition::After(anchor)
}};
}
macro_rules! after_field {
($anchor:expr) => {
if let Some(comma) = $anchor
.syntax()
.siblings_with_tokens(Direction::Next)
.find(|it| it.kind() == T![,])
{
InsertPosition::After(comma)
} else {
to_insert.insert(0, make::token(T![,]).into());
InsertPosition::After($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),
};
self.insert_children(position, to_insert)
}
}
impl ast::TypeParam {
#[must_use]
pub fn remove_bounds(&self) -> ast::TypeParam {
let colon = match self.colon() {
Some(it) => it,
None => return self.clone(),
};
let end = match self.type_bound_list() {
Some(it) => it.syntax().clone().into(),
None => colon.syntax().clone().into(),
};
self.replace_children(colon.syntax().clone().into()..=end, iter::empty())
}
}
impl ast::Path {
#[must_use]
pub fn with_segment(&self, segment: ast::PathSegment) -> ast::Path {
if let Some(old) = self.segment() {
return self.replace_children(
single_node(old.syntax().clone()),
iter::once(segment.syntax().clone().into()),
);
}
self.clone()
}
}
impl ast::PathSegment {
#[must_use]
pub fn with_type_args(&self, type_args: ast::TypeArgList) -> ast::PathSegment {
self._with_type_args(type_args, false)
}
#[must_use]
pub fn with_turbo_fish(&self, type_args: ast::TypeArgList) -> ast::PathSegment {
self._with_type_args(type_args, true)
}
fn _with_type_args(&self, type_args: ast::TypeArgList, turbo: bool) -> ast::PathSegment {
if let Some(old) = self.type_arg_list() {
return self.replace_children(
single_node(old.syntax().clone()),
iter::once(type_args.syntax().clone().into()),
);
}
let mut to_insert: ArrayVec<[SyntaxElement; 2]> = ArrayVec::new();
if turbo {
to_insert.push(make::token(T![::]).into());
}
to_insert.push(type_args.syntax().clone().into());
self.insert_children(InsertPosition::Last, to_insert)
}
}
impl ast::UseItem {
#[must_use]
pub fn with_use_tree(&self, use_tree: ast::UseTree) -> ast::UseItem {
if let Some(old) = self.use_tree() {
return self.replace_descendant(old, use_tree);
}
self.clone()
}
pub fn remove(&self) -> SyntaxRewriter<'static> {
let mut res = SyntaxRewriter::default();
res.delete(self.syntax());
let next_ws = self
.syntax()
.next_sibling_or_token()
.and_then(|it| it.into_token())
.and_then(ast::Whitespace::cast);
if let Some(next_ws) = next_ws {
let ws_text = next_ws.syntax().text();
if ws_text.starts_with('\n') {
let rest = &ws_text[1..];
if rest.is_empty() {
res.delete(next_ws.syntax())
} else {
res.replace(next_ws.syntax(), &make::tokens::whitespace(rest));
}
}
}
res
}
}
impl ast::UseTree {
#[must_use]
pub fn with_path(&self, path: ast::Path) -> ast::UseTree {
if let Some(old) = self.path() {
return self.replace_descendant(old, path);
}
self.clone()
}
#[must_use]
pub fn with_use_tree_list(&self, use_tree_list: ast::UseTreeList) -> ast::UseTree {
if let Some(old) = self.use_tree_list() {
return self.replace_descendant(old, use_tree_list);
}
self.clone()
}
#[must_use]
pub fn split_prefix(&self, prefix: &ast::Path) -> ast::UseTree {
let suffix = match split_path_prefix(&prefix) {
Some(it) => it,
None => return self.clone(),
};
let use_tree = make::use_tree(
suffix.clone(),
self.use_tree_list(),
self.alias(),
self.star_token().is_some(),
);
let nested = make::use_tree_list(iter::once(use_tree));
return make::use_tree(prefix.clone(), Some(nested), None, false);
fn split_path_prefix(prefix: &ast::Path) -> Option<ast::Path> {
let parent = prefix.parent_path()?;
let mut res = make::path_unqualified(parent.segment()?);
for p in iter::successors(parent.parent_path(), |it| it.parent_path()) {
res = make::path_qualified(res, p.segment()?);
}
Some(res)
}
}
pub fn remove(&self) -> SyntaxRewriter<'static> {
let mut res = SyntaxRewriter::default();
res.delete(self.syntax());
for &dir in [Direction::Next, Direction::Prev].iter() {
if let Some(nb) = neighbor(self, dir) {
self.syntax()
.siblings_with_tokens(dir)
.skip(1)
.take_while(|it| it.as_node() != Some(nb.syntax()))
.for_each(|el| res.delete(&el));
return res;
}
}
res
}
}
impl ast::MatchArmList {
#[must_use]
pub fn append_arms(&self, items: impl IntoIterator<Item = ast::MatchArm>) -> ast::MatchArmList {
let mut res = self.clone();
res = res.strip_if_only_whitespace();
if !res.syntax().text().contains_char('\n') {
res = make_multiline(res);
}
items.into_iter().for_each(|it| res = res.append_arm(it));
res
}
fn strip_if_only_whitespace(&self) -> ast::MatchArmList {
let mut iter = self.syntax().children_with_tokens().skip_while(|it| it.kind() != T!['{']);
iter.next(); // Eat the curly
let mut inner = iter.take_while(|it| it.kind() != T!['}']);
if !inner.clone().all(|it| it.kind() == WHITESPACE) {
return self.clone();
}
let start = match inner.next() {
Some(s) => s,
None => return self.clone(),
};
let end = match inner.last() {
Some(s) => s,
None => start.clone(),
};
self.replace_children(start..=end, &mut iter::empty())
}
#[must_use]
pub fn remove_placeholder(&self) -> ast::MatchArmList {
let placeholder =
self.arms().find(|arm| matches!(arm.pat(), Some(ast::Pat::PlaceholderPat(_))));
if let Some(placeholder) = placeholder {
self.remove_arm(&placeholder)
} else {
self.clone()
}
}
#[must_use]
fn remove_arm(&self, arm: &ast::MatchArm) -> ast::MatchArmList {
let start = arm.syntax().clone();
let end = if let Some(comma) = start
.siblings_with_tokens(Direction::Next)
.skip(1)
.skip_while(|it| it.kind().is_trivia())
.next()
.filter(|it| it.kind() == T![,])
{
comma
} else {
start.clone().into()
};
self.replace_children(start.into()..=end, None)
}
#[must_use]
pub fn append_arm(&self, item: ast::MatchArm) -> ast::MatchArmList {
let r_curly = match self.syntax().children_with_tokens().find(|it| it.kind() == T!['}']) {
Some(t) => t,
None => return self.clone(),
};
let position = InsertPosition::Before(r_curly.into());
let arm_ws = tokens::WsBuilder::new(" ");
let match_indent = &leading_indent(self.syntax()).unwrap_or_default();
let match_ws = tokens::WsBuilder::new(&format!("\n{}", match_indent));
let to_insert: ArrayVec<[SyntaxElement; 3]> =
[arm_ws.ws().into(), item.syntax().clone().into(), match_ws.ws().into()].into();
self.insert_children(position, to_insert)
}
}
#[must_use]
pub fn remove_attrs_and_docs<N: ast::AttrsOwner>(node: &N) -> N {
N::cast(remove_attrs_and_docs_inner(node.syntax().clone())).unwrap()
}
fn remove_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, start..=end, &mut iter::empty());
}
node
}
#[derive(Debug, Clone, Copy)]
pub struct IndentLevel(pub u8);
impl From<u8> for IndentLevel {
fn from(level: u8) -> IndentLevel {
IndentLevel(level)
}
}
impl IndentLevel {
pub fn from_node(node: &SyntaxNode) -> IndentLevel {
let first_token = match node.first_token() {
Some(it) => it,
None => return IndentLevel(0),
};
for ws in prev_tokens(first_token).filter_map(ast::Whitespace::cast) {
let text = ws.syntax().text();
if let Some(pos) = text.rfind('\n') {
let level = text[pos + 1..].chars().count() / 4;
return IndentLevel(level as u8);
}
}
IndentLevel(0)
}
pub fn increase_indent<N: AstNode>(self, node: N) -> N {
N::cast(self._increase_indent(node.syntax().clone())).unwrap()
}
fn _increase_indent(self, node: SyntaxNode) -> SyntaxNode {
let mut rewriter = SyntaxRewriter::default();
node.descendants_with_tokens()
.filter_map(|el| el.into_token())
.filter_map(ast::Whitespace::cast)
.filter(|ws| {
let text = ws.syntax().text();
text.contains('\n')
})
.for_each(|ws| {
let new_ws = make::tokens::whitespace(&format!(
"{}{:width$}",
ws.syntax().text(),
"",
width = self.0 as usize * 4
));
rewriter.replace(ws.syntax(), &new_ws)
});
rewriter.rewrite(&node)
}
pub fn decrease_indent<N: AstNode>(self, node: N) -> N {
N::cast(self._decrease_indent(node.syntax().clone())).unwrap()
}
fn _decrease_indent(self, node: SyntaxNode) -> SyntaxNode {
let mut rewriter = SyntaxRewriter::default();
node.descendants_with_tokens()
.filter_map(|el| el.into_token())
.filter_map(ast::Whitespace::cast)
.filter(|ws| {
let text = ws.syntax().text();
text.contains('\n')
})
.for_each(|ws| {
let new_ws = make::tokens::whitespace(
&ws.syntax().text().replace(&format!("\n{:1$}", "", self.0 as usize * 4), "\n"),
);
rewriter.replace(ws.syntax(), &new_ws)
});
rewriter.rewrite(&node)
}
}
// FIXME: replace usages with IndentLevel above
fn leading_indent(node: &SyntaxNode) -> Option<SmolStr> {
for token in prev_tokens(node.first_token()?) {
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
}
fn prev_tokens(token: SyntaxToken) -> impl Iterator<Item = SyntaxToken> {
iter::successors(Some(token), |token| token.prev_token())
}
pub trait AstNodeEdit: AstNode + Sized {
#[must_use]
fn insert_children(
&self,
position: InsertPosition<SyntaxElement>,
to_insert: impl IntoIterator<Item = SyntaxElement>,
) -> Self {
let new_syntax = algo::insert_children(self.syntax(), position, to_insert);
Self::cast(new_syntax).unwrap()
}
#[must_use]
fn replace_children(
&self,
to_replace: RangeInclusive<SyntaxElement>,
to_insert: impl IntoIterator<Item = SyntaxElement>,
) -> Self {
let new_syntax = algo::replace_children(self.syntax(), to_replace, to_insert);
Self::cast(new_syntax).unwrap()
}
#[must_use]
fn replace_descendant<D: AstNode>(&self, old: D, new: D) -> Self {
self.replace_descendants(iter::once((old, new)))
}
#[must_use]
fn replace_descendants<D: AstNode>(
&self,
replacement_map: impl IntoIterator<Item = (D, D)>,
) -> Self {
let mut rewriter = SyntaxRewriter::default();
for (from, to) in replacement_map {
rewriter.replace(from.syntax(), to.syntax())
}
rewriter.rewrite_ast(self)
}
}
impl<N: AstNode> AstNodeEdit for N {}
fn single_node(element: impl Into<SyntaxElement>) -> RangeInclusive<SyntaxElement> {
let element = element.into();
element.clone()..=element
}
#[test]
fn test_increase_indent() {
let arm_list = {
let arm = make::match_arm(iter::once(make::placeholder_pat().into()), make::expr_unit());
make::match_arm_list(vec![arm.clone(), arm])
};
assert_eq!(
arm_list.syntax().to_string(),
"{
_ => (),
_ => (),
}"
);
let indented = IndentLevel(2).increase_indent(arm_list);
assert_eq!(
indented.syntax().to_string(),
"{
_ => (),
_ => (),
}"
);
}