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//! This crate provides some utilities for indenting rust code.
//!
use std::iter::successors;
use itertools::Itertools;
use ra_syntax::{
SyntaxNode, SyntaxKind::*, SyntaxToken, SyntaxKind,
ast::{self, AstNode, AstToken},
};
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<&str> {
for token in prev_tokens(node.first_token()?) {
if let Some(ws) = ast::Whitespace::cast(token) {
let ws_text = ws.text();
if let Some(pos) = ws_text.rfind('\n') {
return Some(&ws_text[pos + 1..]);
}
}
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(block: &ast::Block) -> Option<&ast::Expr> {
let expr = block.expr()?;
if expr.syntax().text().contains('\n') {
return None;
}
let non_trivial_children = block.syntax().children().filter(|it| match it.kind() {
WHITESPACE | L_CURLY | R_CURLY => 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 {
L_PAREN | L_BRACK => return "",
L_CURLY => {
if let USE_TREE = right {
return "";
}
}
_ => (),
}
match right {
R_PAREN | R_BRACK => return "",
R_CURLY => {
if let USE_TREE = left {
return "";
}
}
DOT => return "",
_ => (),
}
" "
}
|
