120 lines
4.0 KiB
Rust
120 lines
4.0 KiB
Rust
//! Utilities for formatting macro expanded nodes until we get a proper formatter.
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use syntax::{
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ast::make,
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ted::{self, Position},
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NodeOrToken,
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SyntaxKind::{self, *},
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SyntaxNode, SyntaxToken, WalkEvent, T,
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};
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// FIXME: It would also be cool to share logic here and in the mbe tests,
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// which are pretty unreadable at the moment.
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/// Renders a [`SyntaxNode`] with whitespace inserted between tokens that require them.
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pub fn insert_ws_into(syn: SyntaxNode) -> SyntaxNode {
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let mut indent = 0;
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let mut last: Option<SyntaxKind> = None;
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let mut mods = Vec::new();
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let syn = syn.clone_subtree().clone_for_update();
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let before = Position::before;
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let after = Position::after;
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let do_indent = |pos: fn(_) -> Position, token: &SyntaxToken, indent| {
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(pos(token.clone()), make::tokens::whitespace(&" ".repeat(2 * indent)))
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};
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let do_ws = |pos: fn(_) -> Position, token: &SyntaxToken| {
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(pos(token.clone()), make::tokens::single_space())
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};
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let do_nl = |pos: fn(_) -> Position, token: &SyntaxToken| {
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(pos(token.clone()), make::tokens::single_newline())
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};
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for event in syn.preorder_with_tokens() {
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let token = match event {
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WalkEvent::Enter(NodeOrToken::Token(token)) => token,
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WalkEvent::Leave(NodeOrToken::Node(node))
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if matches!(node.kind(), ATTR | MATCH_ARM | STRUCT | ENUM | UNION | FN | IMPL) =>
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{
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if indent > 0 {
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mods.push((
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Position::after(node.clone()),
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make::tokens::whitespace(&" ".repeat(2 * indent)),
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));
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}
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if node.parent().is_some() {
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mods.push((Position::after(node), make::tokens::single_newline()));
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}
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continue;
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}
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_ => continue,
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};
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let tok = &token;
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let is_next = |f: fn(SyntaxKind) -> bool, default| -> bool {
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tok.next_token().map(|it| f(it.kind())).unwrap_or(default)
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};
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let is_last =
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|f: fn(SyntaxKind) -> bool, default| -> bool { last.map(f).unwrap_or(default) };
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match tok.kind() {
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k if is_text(k) && is_next(|it| !it.is_punct(), true) => {
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mods.push(do_ws(after, tok));
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}
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L_CURLY if is_next(|it| it != R_CURLY, true) => {
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indent += 1;
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if is_last(is_text, false) {
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mods.push(do_ws(before, tok));
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}
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if indent > 0 {
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mods.push(do_indent(after, tok, indent));
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}
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mods.push(do_nl(after, &tok));
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}
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R_CURLY if is_last(|it| it != L_CURLY, true) => {
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indent = indent.saturating_sub(1);
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if indent > 0 {
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mods.push(do_indent(before, tok, indent));
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}
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mods.push(do_nl(before, tok));
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}
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R_CURLY => {
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if indent > 0 {
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mods.push(do_indent(after, tok, indent));
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}
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mods.push(do_nl(after, tok));
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}
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LIFETIME_IDENT if is_next(|it| is_text(it), true) => {
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mods.push(do_ws(after, tok));
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}
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AS_KW | DYN_KW | IMPL_KW => {
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mods.push(do_ws(after, tok));
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}
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T![;] => {
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if indent > 0 {
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mods.push(do_indent(after, tok, indent));
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}
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mods.push(do_nl(after, tok));
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}
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T![->] | T![=] | T![=>] => {
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mods.push(do_ws(before, tok));
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mods.push(do_ws(after, tok));
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}
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_ => (),
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}
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last = Some(tok.kind());
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}
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for (pos, insert) in mods {
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ted::insert(pos, insert);
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}
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syn
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}
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fn is_text(k: SyntaxKind) -> bool {
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k.is_keyword() || k.is_literal() || k == IDENT
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}
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