| //! 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 unwrap_trivial_block(block: ast::BlockExpr) -> ast::Expr { |
| extract_trivial_expression(&block) |
| .filter(|expr| !expr.syntax().text().contains_char('\n')) |
| .unwrap_or_else(|| block.into()) |
| } |
| |
| pub fn extract_trivial_expression(block: &ast::BlockExpr) -> Option<ast::Expr> { |
| let has_anything_else = |thing: &SyntaxNode| -> bool { |
| let mut non_trivial_children = |
| block.syntax().children_with_tokens().filter(|it| match it.kind() { |
| WHITESPACE | T!['{'] | T!['}'] => false, |
| _ => it.as_node() != Some(thing), |
| }); |
| non_trivial_children.next().is_some() |
| }; |
| |
| if let Some(expr) = block.expr() { |
| if has_anything_else(expr.syntax()) { |
| return None; |
| } |
| return Some(expr); |
| } |
| // Unwrap `{ continue; }` |
| let (stmt,) = block.statements().next_tuple()?; |
| if let ast::Stmt::ExprStmt(expr_stmt) = stmt { |
| if has_anything_else(expr_stmt.syntax()) { |
| return None; |
| } |
| let expr = expr_stmt.expr()?; |
| match expr.syntax().kind() { |
| CONTINUE_EXPR | BREAK_EXPR | RETURN_EXPR => return Some(expr), |
| _ => (), |
| } |
| } |
| None |
| } |
| |
| 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 "", |
| _ => (), |
| } |
| " " |
| } |