bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/syntax-bridge/src/prettify_macro_expansion.rs')
-rw-r--r--crates/syntax-bridge/src/prettify_macro_expansion.rs149
1 files changed, 149 insertions, 0 deletions
diff --git a/crates/syntax-bridge/src/prettify_macro_expansion.rs b/crates/syntax-bridge/src/prettify_macro_expansion.rs
new file mode 100644
index 0000000000..fc7caaa988
--- /dev/null
+++ b/crates/syntax-bridge/src/prettify_macro_expansion.rs
@@ -0,0 +1,149 @@
+//! Utilities for formatting macro expanded nodes until we get a proper formatter.
+use syntax::{
+ ast::make,
+ ted::{self, Position},
+ NodeOrToken,
+ SyntaxKind::{self, *},
+ SyntaxNode, SyntaxToken, WalkEvent, T,
+};
+
+/// Renders a [`SyntaxNode`] with whitespace inserted between tokens that require them.
+///
+/// This is an internal API that is only exported because `mbe` needs it for tests and cannot depend
+/// on `hir-expand`. For any purpose other than tests, you are supposed to use the `prettify_macro_expansion`
+/// from `hir-expand` that handles `$crate` for you.
+#[deprecated = "use `hir_expand::prettify_macro_expansion()` instead"]
+pub fn prettify_macro_expansion(
+ syn: SyntaxNode,
+ dollar_crate_replacement: &mut dyn FnMut(&SyntaxToken) -> SyntaxToken,
+) -> SyntaxNode {
+ let mut indent = 0;
+ let mut last: Option<SyntaxKind> = None;
+ let mut mods = Vec::new();
+ let mut dollar_crate_replacements = Vec::new();
+ let syn = syn.clone_subtree().clone_for_update();
+
+ let before = Position::before;
+ let after = Position::after;
+
+ let do_indent = |pos: fn(_) -> Position, token: &SyntaxToken, indent| {
+ (pos(token.clone()), make::tokens::whitespace(&" ".repeat(4 * indent)))
+ };
+ let do_ws = |pos: fn(_) -> Position, token: &SyntaxToken| {
+ (pos(token.clone()), make::tokens::single_space())
+ };
+ let do_nl = |pos: fn(_) -> Position, token: &SyntaxToken| {
+ (pos(token.clone()), make::tokens::single_newline())
+ };
+
+ for event in syn.preorder_with_tokens() {
+ let token = match event {
+ WalkEvent::Enter(NodeOrToken::Token(token)) => token,
+ WalkEvent::Leave(NodeOrToken::Node(node))
+ if matches!(
+ node.kind(),
+ ATTR | MATCH_ARM | STRUCT | ENUM | UNION | FN | IMPL | MACRO_RULES
+ ) =>
+ {
+ if indent > 0 {
+ mods.push((
+ Position::after(node.clone()),
+ make::tokens::whitespace(&" ".repeat(4 * indent)),
+ ));
+ }
+ if node.parent().is_some() {
+ mods.push((Position::after(node), make::tokens::single_newline()));
+ }
+ continue;
+ }
+ _ => continue,
+ };
+ if token.kind() == SyntaxKind::IDENT && token.text() == "$crate" {
+ dollar_crate_replacements.push((token.clone(), dollar_crate_replacement(&token)));
+ }
+ let tok = &token;
+
+ let is_next = |f: fn(SyntaxKind) -> bool, default| -> bool {
+ tok.next_token().map(|it| f(it.kind())).unwrap_or(default)
+ };
+ let is_last =
+ |f: fn(SyntaxKind) -> bool, default| -> bool { last.map(f).unwrap_or(default) };
+
+ match tok.kind() {
+ k if is_text(k)
+ && is_next(|it| !it.is_punct() || matches!(it, T![_] | T![#]), false) =>
+ {
+ mods.push(do_ws(after, tok));
+ }
+ L_CURLY if is_next(|it| it != R_CURLY, true) => {
+ indent += 1;
+ if is_last(is_text, false) {
+ mods.push(do_ws(before, tok));
+ }
+
+ mods.push(do_indent(after, tok, indent));
+ mods.push(do_nl(after, tok));
+ }
+ R_CURLY if is_last(|it| it != L_CURLY, true) => {
+ indent = indent.saturating_sub(1);
+
+ if indent > 0 {
+ mods.push(do_indent(before, tok, indent));
+ }
+ mods.push(do_nl(before, tok));
+ }
+ R_CURLY => {
+ if indent > 0 {
+ mods.push(do_indent(after, tok, indent));
+ }
+ mods.push(do_nl(after, tok));
+ }
+ LIFETIME_IDENT if is_next(is_text, true) => {
+ mods.push(do_ws(after, tok));
+ }
+ AS_KW | DYN_KW | IMPL_KW | CONST_KW | MUT_KW => {
+ mods.push(do_ws(after, tok));
+ }
+ T![;] if is_next(|it| it != R_CURLY, true) => {
+ if indent > 0 {
+ mods.push(do_indent(after, tok, indent));
+ }
+ mods.push(do_nl(after, tok));
+ }
+ T![=] if is_next(|it| it == T![>], false) => {
+ // FIXME: this branch is for `=>` in macro_rules!, which is currently parsed as
+ // two separate symbols.
+ mods.push(do_ws(before, tok));
+ mods.push(do_ws(after, &tok.next_token().unwrap()));
+ }
+ T![->] | T![=] | T![=>] => {
+ mods.push(do_ws(before, tok));
+ mods.push(do_ws(after, tok));
+ }
+ T![!] if is_last(|it| it == MACRO_RULES_KW, false) && is_next(is_text, false) => {
+ mods.push(do_ws(after, tok));
+ }
+ _ => (),
+ }
+
+ last = Some(tok.kind());
+ }
+
+ for (pos, insert) in mods {
+ ted::insert(pos, insert);
+ }
+ for (old, new) in dollar_crate_replacements {
+ ted::replace(old, new);
+ }
+
+ if let Some(it) = syn.last_token().filter(|it| it.kind() == SyntaxKind::WHITESPACE) {
+ ted::remove(it);
+ }
+
+ syn
+}
+
+fn is_text(k: SyntaxKind) -> bool {
+ // Consider all keywords in all editions.
+ k.is_any_identifier() || k.is_literal() || k == UNDERSCORE
+}