77 lines
2.0 KiB
Rust
77 lines
2.0 KiB
Rust
//! This crate provides some utilities for indenting rust code.
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//!
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use itertools::Itertools;
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use ra_syntax::{
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AstNode,
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SyntaxNode, SyntaxKind::*,
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ast::{self, AstToken},
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algo::generate,
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};
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pub fn reindent(text: &str, indent: &str) -> String {
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let indent = format!("\n{}", indent);
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text.lines().intersperse(&indent).collect()
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}
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/// If the node is on the beginning of the line, calculate indent.
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pub fn leading_indent(node: &SyntaxNode) -> Option<&str> {
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for leaf in prev_leaves(node) {
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if let Some(ws) = ast::Whitespace::cast(leaf) {
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let ws_text = ws.text();
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if let Some(pos) = ws_text.rfind('\n') {
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return Some(&ws_text[pos + 1..]);
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}
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}
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if leaf.leaf_text().unwrap().contains('\n') {
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break;
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}
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}
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None
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}
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fn prev_leaves(node: &SyntaxNode) -> impl Iterator<Item = &SyntaxNode> {
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generate(prev_leaf(node), |&node| prev_leaf(node))
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}
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fn prev_leaf(node: &SyntaxNode) -> Option<&SyntaxNode> {
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generate(node.ancestors().find_map(SyntaxNode::prev_sibling), |it| it.last_child()).last()
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}
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pub fn extract_trivial_expression(block: &ast::Block) -> Option<&ast::Expr> {
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let expr = block.expr()?;
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if expr.syntax().text().contains('\n') {
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return None;
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}
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let non_trivial_children = block.syntax().children().filter(|it| match it.kind() {
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WHITESPACE | L_CURLY | R_CURLY => false,
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_ => it != &expr.syntax(),
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});
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if non_trivial_children.count() > 0 {
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return None;
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}
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Some(expr)
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}
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pub fn compute_ws(left: &SyntaxNode, right: &SyntaxNode) -> &'static str {
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match left.kind() {
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L_PAREN | L_BRACK => return "",
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L_CURLY => {
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if let USE_TREE = right.kind() {
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return "";
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}
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}
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_ => (),
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}
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match right.kind() {
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R_PAREN | R_BRACK => return "",
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R_CURLY => {
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if let USE_TREE = left.kind() {
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return "";
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}
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}
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DOT => return "",
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_ => (),
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}
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" "
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}
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