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//! This crate provides some utilities for indenting rust code.
use std::iter::successors;
use itertools::Itertools;
use ra_syntax::{
ast::{self, AstNode, AstToken},
SmolStr, SyntaxKind,
SyntaxKind::*,
SyntaxNode, SyntaxToken, T,
};
pub fn reindent(text: &str, indent: &str) -> String {
let indent = format!("\n{}", indent);
text.lines().intersperse(&indent).collect()
}
/// If the node is on the beginning of the line, calculate indent.
pub 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> {
successors(token.prev_token(), |token| token.prev_token())
}
pub fn extract_trivial_expression(expr: &ast::BlockExpr) -> Option<ast::Expr> {
let block = expr.block()?;
let expr = block.expr()?;
if expr.syntax().text().contains_char('\n') {
return None;
}
let non_trivial_children = block.syntax().children().filter(|it| match it.kind() {
WHITESPACE | T!['{'] | T!['}'] => false,
_ => it != expr.syntax(),
});
if non_trivial_children.count() > 0 {
return None;
}
Some(expr)
}
pub fn compute_ws(left: SyntaxKind, right: SyntaxKind) -> &'static str {
match left {
T!['('] | T!['['] => return "",
T!['{'] => {
if let USE_TREE = right {
return "";
}
}
_ => (),
}
match right {
T![')'] | T![']'] => return "",
T!['}'] => {
if let USE_TREE = left {
return "";
}
}
T![.] => return "",
_ => (),
}
" "
}
|
