1 // Format list-like macro invocations. These are invocations whose token trees
2 // can be interpreted as expressions and separated by commas.
3 // Note that these token trees do not actually have to be interpreted as
4 // expressions by the compiler. An example of an invocation we would reformat is
5 // foo!( x, y, z ). The token x may represent an identifier in the code, but we
6 // interpreted as an expression.
7 // Macro uses which are not-list like, such as bar!(key => val), will not be
9 // List-like invocations with parentheses will be formatted as function calls,
10 // and those with brackets will be formatted as array literals.
12 use std::collections::HashMap;
13 use std::panic::{catch_unwind, AssertUnwindSafe};
15 use rustc_ast::token::{BinOpToken, DelimToken, Token, TokenKind};
16 use rustc_ast::tokenstream::{Cursor, Spacing, TokenStream, TokenTree};
17 use rustc_ast::{ast, ptr};
18 use rustc_ast_pretty::pprust;
19 use rustc_parse::parser::{ForceCollect, Parser};
20 use rustc_parse::{stream_to_parser, MACRO_ARGUMENTS};
23 BytePos, Span, Symbol, DUMMY_SP,
27 contains_comment, CharClasses, FindUncommented, FullCodeCharKind, LineClasses,
29 use crate::config::lists::*;
30 use crate::expr::rewrite_array;
31 use crate::lists::{itemize_list, write_list, ListFormatting};
33 use crate::rewrite::{Rewrite, RewriteContext};
34 use crate::shape::{Indent, Shape};
35 use crate::source_map::SpanUtils;
36 use crate::spanned::Spanned;
38 format_visibility, indent_next_line, is_empty_line, mk_sp, remove_trailing_white_spaces,
39 rewrite_ident, trim_left_preserve_layout, wrap_str, NodeIdExt,
41 use crate::visitor::FmtVisitor;
43 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
45 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
46 pub(crate) enum MacroPosition {
54 pub(crate) enum MacroArg {
55 Expr(ptr::P<ast::Expr>),
57 Pat(ptr::P<ast::Pat>),
58 Item(ptr::P<ast::Item>),
59 Keyword(symbol::Ident, Span),
63 fn is_item(&self) -> bool {
65 MacroArg::Item(..) => true,
71 impl Rewrite for ast::Item {
72 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
73 let mut visitor = crate::visitor::FmtVisitor::from_context(context);
74 visitor.block_indent = shape.indent;
75 visitor.last_pos = self.span().lo();
76 visitor.visit_item(self);
77 Some(visitor.buffer.to_owned())
81 impl Rewrite for MacroArg {
82 fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
84 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
85 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
86 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
87 MacroArg::Item(ref item) => item.rewrite(context, shape),
88 MacroArg::Keyword(ident, _) => Some(ident.name.to_string()),
93 fn build_parser<'a>(context: &RewriteContext<'a>, cursor: Cursor) -> Parser<'a> {
95 context.parse_sess.inner(),
101 fn parse_macro_arg<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
102 macro_rules! parse_macro_arg {
103 ($macro_arg:ident, $parser:expr, $f:expr) => {
104 let mut cloned_parser = (*parser).clone();
105 match $parser(&mut cloned_parser) {
107 if parser.sess.span_diagnostic.has_errors() {
108 parser.sess.span_diagnostic.reset_err_count();
110 // Parsing succeeded.
111 *parser = cloned_parser;
112 return Some(MacroArg::$macro_arg($f(x)?));
117 parser.sess.span_diagnostic.reset_err_count();
125 |parser: &mut rustc_parse::parser::Parser<'b>| parser.parse_expr(),
126 |x: ptr::P<ast::Expr>| Some(x)
130 |parser: &mut rustc_parse::parser::Parser<'b>| parser.parse_ty(),
131 |x: ptr::P<ast::Ty>| Some(x)
135 |parser: &mut rustc_parse::parser::Parser<'b>| parser.parse_pat_no_top_alt(None),
136 |x: ptr::P<ast::Pat>| Some(x)
138 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
141 |parser: &mut rustc_parse::parser::Parser<'b>| parser.parse_item(ForceCollect::No),
142 |x: Option<ptr::P<ast::Item>>| x
148 /// Rewrite macro name without using pretty-printer if possible.
149 fn rewrite_macro_name(
150 context: &RewriteContext<'_>,
152 extra_ident: Option<symbol::Ident>,
154 let name = if path.segments.len() == 1 {
155 // Avoid using pretty-printer in the common case.
156 format!("{}!", rewrite_ident(context, path.segments[0].ident))
158 format!("{}!", pprust::path_to_string(path))
161 Some(ident) if ident.name != kw::Empty => format!("{} {}", name, ident),
166 // Use this on failing to format the macro call.
167 fn return_macro_parse_failure_fallback(
168 context: &RewriteContext<'_>,
171 ) -> Option<String> {
172 // Mark this as a failure however we format it
173 context.macro_rewrite_failure.replace(true);
175 // Heuristically determine whether the last line of the macro uses "Block" style
176 // rather than using "Visual" style, or another indentation style.
177 let is_like_block_indent_style = context
181 .map(|closing_line| {
182 closing_line.trim().chars().all(|ch| match ch {
183 '}' | ')' | ']' => true,
188 if is_like_block_indent_style {
189 return trim_left_preserve_layout(context.snippet(span), indent, &context.config);
192 context.skipped_range.borrow_mut().push((
193 context.parse_sess.line_of_byte_pos(span.lo()),
194 context.parse_sess.line_of_byte_pos(span.hi()),
197 // Return the snippet unmodified if the macro is not block-like
198 Some(context.snippet(span).to_owned())
201 pub(crate) fn rewrite_macro(
203 extra_ident: Option<symbol::Ident>,
204 context: &RewriteContext<'_>,
206 position: MacroPosition,
207 ) -> Option<String> {
208 let should_skip = context
210 .skip_macro(&context.snippet(mac.path.span).to_owned());
214 let guard = context.enter_macro();
215 let result = catch_unwind(AssertUnwindSafe(|| {
226 Err(..) | Ok(None) => {
227 context.macro_rewrite_failure.replace(true);
235 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
236 for &keyword in RUST_KW.iter() {
237 if parser.token.is_keyword(keyword)
238 && parser.look_ahead(1, |t| {
239 t.kind == TokenKind::Eof
240 || t.kind == TokenKind::Comma
241 || t.kind == TokenKind::CloseDelim(DelimToken::NoDelim)
245 return Some(MacroArg::Keyword(
246 symbol::Ident::with_dummy_span(keyword),
247 parser.prev_token.span,
254 fn rewrite_macro_inner(
256 extra_ident: Option<symbol::Ident>,
257 context: &RewriteContext<'_>,
259 position: MacroPosition,
260 is_nested_macro: bool,
261 ) -> Option<String> {
262 if context.config.use_try_shorthand() {
263 if let Some(expr) = convert_try_mac(mac, context) {
264 context.leave_macro();
265 return expr.rewrite(context, shape);
269 let original_style = macro_style(mac, context);
271 let macro_name = rewrite_macro_name(context, &mac.path, extra_ident);
273 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) && !is_nested_macro {
279 let ts = mac.args.inner_tokens();
280 let has_comment = contains_comment(context.snippet(mac.span()));
281 if ts.is_empty() && !has_comment {
283 DelimToken::Paren if position == MacroPosition::Item => {
284 Some(format!("{}();", macro_name))
286 DelimToken::Bracket if position == MacroPosition::Item => {
287 Some(format!("{}[];", macro_name))
289 DelimToken::Paren => Some(format!("{}()", macro_name)),
290 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
291 DelimToken::Brace => Some(format!("{} {{}}", macro_name)),
295 // Format well-known macros which cannot be parsed as a valid AST.
296 if macro_name == "lazy_static!" && !has_comment {
297 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
302 let mut parser = build_parser(context, ts.trees());
303 let mut arg_vec = Vec::new();
304 let mut vec_with_semi = false;
305 let mut trailing_comma = false;
307 if DelimToken::Brace != style {
309 if let Some(arg) = check_keyword(&mut parser) {
311 } else if let Some(arg) = parse_macro_arg(&mut parser) {
314 return return_macro_parse_failure_fallback(context, shape.indent, mac.span());
317 match parser.token.kind {
318 TokenKind::Eof => break,
319 TokenKind::Comma => (),
321 // Try to parse `vec![expr; expr]`
322 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
324 if parser.token.kind != TokenKind::Eof {
325 match parse_macro_arg(&mut parser) {
329 if parser.token.kind == TokenKind::Eof && arg_vec.len() == 2 {
330 vec_with_semi = true;
335 return return_macro_parse_failure_fallback(
344 return return_macro_parse_failure_fallback(context, shape.indent, mac.span());
346 _ if arg_vec.last().map_or(false, MacroArg::is_item) => continue,
347 _ => return return_macro_parse_failure_fallback(context, shape.indent, mac.span()),
352 if parser.token.kind == TokenKind::Eof {
353 trailing_comma = true;
359 if !arg_vec.is_empty() && arg_vec.iter().all(MacroArg::is_item) {
360 return rewrite_macro_with_items(
372 DelimToken::Paren => {
373 // Handle special case: `vec!(expr; expr)`
375 handle_vec_semi(context, shape, arg_vec, macro_name, style)
377 // Format macro invocation as function call, preserve the trailing
378 // comma because not all macros support them.
379 overflow::rewrite_with_parens(
385 context.config.fn_call_width(),
387 Some(SeparatorTactic::Always)
389 Some(SeparatorTactic::Never)
392 .map(|rw| match position {
393 MacroPosition::Item => format!("{};", rw),
398 DelimToken::Bracket => {
399 // Handle special case: `vec![expr; expr]`
401 handle_vec_semi(context, shape, arg_vec, macro_name, style)
403 // If we are rewriting `vec!` macro or other special macros,
404 // then we can rewrite this as an usual array literal.
405 // Otherwise, we must preserve the original existence of trailing comma.
406 let macro_name = ¯o_name.as_str();
407 let mut force_trailing_comma = if trailing_comma {
408 Some(SeparatorTactic::Always)
410 Some(SeparatorTactic::Never)
412 if FORCED_BRACKET_MACROS.contains(macro_name) && !is_nested_macro {
413 context.leave_macro();
414 if context.use_block_indent() {
415 force_trailing_comma = Some(SeparatorTactic::Vertical);
418 let rewrite = rewrite_array(
424 force_trailing_comma,
425 Some(original_style),
427 let comma = match position {
428 MacroPosition::Item => ";",
432 Some(format!("{}{}", rewrite, comma))
435 DelimToken::Brace => {
436 // For macro invocations with braces, always put a space between
437 // the `macro_name!` and `{ /* macro_body */ }` but skip modifying
438 // anything in between the braces (for now).
439 let snippet = context.snippet(mac.span()).trim_start_matches(|c| c != '{');
440 match trim_left_preserve_layout(snippet, shape.indent, &context.config) {
441 Some(macro_body) => Some(format!("{} {}", macro_name, macro_body)),
442 None => Some(format!("{} {}", macro_name, snippet)),
450 context: &RewriteContext<'_>,
452 arg_vec: Vec<MacroArg>,
454 delim_token: DelimToken,
455 ) -> Option<String> {
456 let (left, right) = match delim_token {
457 DelimToken::Paren => ("(", ")"),
458 DelimToken::Bracket => ("[", "]"),
462 let mac_shape = shape.offset_left(macro_name.len())?;
463 // 8 = `vec![]` + `; ` or `vec!()` + `; `
464 let total_overhead = 8;
465 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
466 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
467 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
468 if !lhs.contains('\n')
469 && !rhs.contains('\n')
470 && lhs.len() + rhs.len() + total_overhead <= shape.width
472 // macro_name(lhs; rhs) or macro_name[lhs; rhs]
473 Some(format!("{}{}{}; {}{}", macro_name, left, lhs, rhs, right))
475 // macro_name(\nlhs;\nrhs\n) or macro_name[\nlhs;\nrhs\n]
480 nested_shape.indent.to_string_with_newline(context.config),
482 nested_shape.indent.to_string_with_newline(context.config),
484 shape.indent.to_string_with_newline(context.config),
490 pub(crate) fn rewrite_macro_def(
491 context: &RewriteContext<'_>,
495 ident: symbol::Ident,
496 vis: &ast::Visibility,
498 ) -> Option<String> {
499 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
500 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
504 let ts = def.body.inner_tokens();
505 let mut parser = MacroParser::new(ts.into_trees());
506 let parsed_def = match parser.parse() {
508 None => return snippet,
511 let mut result = if def.macro_rules {
512 String::from("macro_rules!")
514 format!("{}macro", format_visibility(context, vis))
518 result += rewrite_ident(context, ident);
520 let multi_branch_style = def.macro_rules || parsed_def.branches.len() != 1;
522 let arm_shape = if multi_branch_style {
524 .block_indent(context.config.tab_spaces())
525 .with_max_width(context.config)
530 let branch_items = itemize_list(
531 context.snippet_provider,
532 parsed_def.branches.iter(),
535 |branch| branch.span.lo(),
536 |branch| branch.span.hi(),
537 |branch| match branch.rewrite(context, arm_shape, multi_branch_style) {
539 // if the rewrite returned None because a macro could not be rewritten, then return the
541 None if context.macro_rewrite_failure.get() => {
542 Some(context.snippet(branch.body).trim().to_string())
546 context.snippet_provider.span_after(span, "{"),
550 .collect::<Vec<_>>();
552 let fmt = ListFormatting::new(arm_shape, context.config)
553 .separator(if def.macro_rules { ";" } else { "" })
554 .trailing_separator(SeparatorTactic::Always)
555 .preserve_newline(true);
557 if multi_branch_style {
559 result += &arm_shape.indent.to_string_with_newline(context.config);
562 match write_list(&branch_items, &fmt) {
563 Some(ref s) => result += s,
564 None => return snippet,
567 if multi_branch_style {
568 result += &indent.to_string_with_newline(context.config);
575 fn register_metavariable(
576 map: &mut HashMap<String, String>,
581 let mut new_name = "$".repeat(dollar_count - 1);
582 let mut old_name = "$".repeat(dollar_count);
585 new_name.push_str(name);
586 old_name.push_str(name);
588 result.push_str(&new_name);
589 map.insert(old_name, new_name);
592 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
593 // aren't causing problems.
594 // This should also work for escaped `$` variables, where we leave earlier `$`s.
595 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
596 // Each substitution will require five or six extra bytes.
597 let mut result = String::with_capacity(input.len() + 64);
598 let mut substs = HashMap::new();
599 let mut dollar_count = 0;
600 let mut cur_name = String::new();
602 for (kind, c) in CharClasses::new(input.chars()) {
603 if kind != FullCodeCharKind::Normal {
607 } else if dollar_count == 0 {
609 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
610 // Terminates a name following one or more dollars.
611 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
616 } else if c == '(' && cur_name.is_empty() {
617 // FIXME: Support macro def with repeat.
619 } else if c.is_alphanumeric() || c == '_' {
624 if !cur_name.is_empty() {
625 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
628 debug!("replace_names `{}` {:?}", result, substs);
630 Some((result, substs))
633 #[derive(Debug, Clone)]
635 /// e.g., `$x: expr`.
636 MetaVariable(Symbol, String),
637 /// e.g., `$($foo: expr),*`
639 /// `()`, `[]` or `{}`.
641 /// Inner arguments inside delimiters.
643 /// Something after the closing delimiter and the repeat token, if available.
644 Option<Box<ParsedMacroArg>>,
645 /// The repeat token. This could be one of `*`, `+` or `?`.
648 /// e.g., `[derive(Debug)]`
649 Delimited(DelimToken, Vec<ParsedMacroArg>),
650 /// A possible separator. e.g., `,` or `;`.
651 Separator(String, String),
652 /// Other random stuff that does not fit to other kinds.
653 /// e.g., `== foo` in `($x: expr == foo)`.
654 Other(String, String),
657 fn delim_token_to_str(
658 context: &RewriteContext<'_>,
659 delim_token: DelimToken,
661 use_multiple_lines: bool,
662 inner_is_empty: bool,
663 ) -> (String, String) {
664 let (lhs, rhs) = match delim_token {
665 DelimToken::Paren => ("(", ")"),
666 DelimToken::Bracket => ("[", "]"),
667 DelimToken::Brace => {
668 if inner_is_empty || use_multiple_lines {
674 DelimToken::NoDelim => ("", ""),
676 if use_multiple_lines {
677 let indent_str = shape.indent.to_string_with_newline(context.config);
678 let nested_indent_str = shape
680 .block_indent(context.config)
681 .to_string_with_newline(context.config);
683 format!("{}{}", lhs, nested_indent_str),
684 format!("{}{}", indent_str, rhs),
687 (lhs.to_owned(), rhs.to_owned())
692 fn starts_with_brace(&self) -> bool {
694 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
695 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
700 fn starts_with_dollar(&self) -> bool {
702 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
707 fn ends_with_space(&self) -> bool {
709 MacroArgKind::Separator(..) => true,
714 fn has_meta_var(&self) -> bool {
716 MacroArgKind::MetaVariable(..) => true,
717 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
724 context: &RewriteContext<'_>,
726 use_multiple_lines: bool,
727 ) -> Option<String> {
728 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
729 let inner = wrap_macro_args(context, args, shape)?;
730 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
731 if lhs.len() + inner.len() + rhs.len() <= shape.width {
732 return Some((lhs, inner, rhs));
735 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
736 let nested_shape = shape
737 .block_indent(context.config.tab_spaces())
738 .with_max_width(context.config);
739 let inner = wrap_macro_args(context, args, nested_shape)?;
740 Some((lhs, inner, rhs))
744 MacroArgKind::MetaVariable(ty, ref name) => Some(format!("${}:{}", name, ty)),
745 MacroArgKind::Repeat(delim_tok, ref args, ref another, ref tok) => {
746 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
747 let another = another
749 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
750 .unwrap_or_else(|| "".to_owned());
751 let repeat_tok = pprust::token_to_string(tok);
753 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
755 MacroArgKind::Delimited(delim_tok, ref args) => {
756 rewrite_delimited_inner(delim_tok, args)
757 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
759 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
760 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
765 #[derive(Debug, Clone)]
766 struct ParsedMacroArg {
771 impl ParsedMacroArg {
774 context: &RewriteContext<'_>,
776 use_multiple_lines: bool,
777 ) -> Option<String> {
778 self.kind.rewrite(context, shape, use_multiple_lines)
782 /// Parses macro arguments on macro def.
783 struct MacroArgParser {
784 /// Either a name of the next metavariable, a separator, or junk.
786 /// The start position on the current buffer.
788 /// The first token of the current buffer.
790 /// `true` if we are parsing a metavariable or a repeat.
792 /// The position of the last token.
794 /// The last token parsed.
796 /// Holds the parsed arguments.
797 result: Vec<ParsedMacroArg>,
800 fn last_tok(tt: &TokenTree) -> Token {
802 TokenTree::Token(ref t) => t.clone(),
803 TokenTree::Delimited(delim_span, delim, _) => Token {
804 kind: TokenKind::CloseDelim(delim),
805 span: delim_span.close,
810 impl MacroArgParser {
811 fn new() -> MacroArgParser {
818 kind: TokenKind::Eof,
822 kind: TokenKind::Eof,
829 fn set_last_tok(&mut self, tok: &TokenTree) {
830 self.hi = tok.span().hi();
831 self.last_tok = last_tok(tok);
834 fn add_separator(&mut self) {
835 let prefix = if self.need_space_prefix() {
840 self.result.push(ParsedMacroArg {
841 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
842 span: mk_sp(self.lo, self.hi),
847 fn add_other(&mut self) {
848 let prefix = if self.need_space_prefix() {
853 self.result.push(ParsedMacroArg {
854 kind: MacroArgKind::Other(self.buf.clone(), prefix),
855 span: mk_sp(self.lo, self.hi),
860 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
862 Some(TokenTree::Token(Token {
863 kind: TokenKind::Ident(name, _),
866 self.result.push(ParsedMacroArg {
867 kind: MacroArgKind::MetaVariable(name, self.buf.clone()),
868 span: mk_sp(self.lo, span.hi()),
872 self.is_meta_var = false;
879 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
880 self.result.push(ParsedMacroArg {
881 kind: MacroArgKind::Delimited(delim, inner),
889 inner: Vec<ParsedMacroArg>,
894 let mut buffer = String::new();
895 let mut first = true;
896 let mut lo = span.lo();
897 let mut hi = span.hi();
899 // Parse '*', '+' or '?.
901 self.set_last_tok(&tok);
904 lo = tok.span().lo();
908 TokenTree::Token(Token {
909 kind: TokenKind::BinOp(BinOpToken::Plus),
912 | TokenTree::Token(Token {
913 kind: TokenKind::Question,
916 | TokenTree::Token(Token {
917 kind: TokenKind::BinOp(BinOpToken::Star),
922 TokenTree::Token(ref t) => {
923 buffer.push_str(&pprust::token_to_string(&t));
930 // There could be some random stuff between ')' and '*', '+' or '?'.
931 let another = if buffer.trim().is_empty() {
934 Some(Box::new(ParsedMacroArg {
935 kind: MacroArgKind::Other(buffer, "".to_owned()),
940 self.result.push(ParsedMacroArg {
941 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
942 span: mk_sp(self.lo, self.hi),
947 fn update_buffer(&mut self, t: &Token) {
948 if self.buf.is_empty() {
949 self.lo = t.span.lo();
950 self.start_tok = t.clone();
952 let needs_space = match next_space(&self.last_tok.kind) {
953 SpaceState::Ident => ident_like(t),
954 SpaceState::Punctuation => !ident_like(t),
955 SpaceState::Always => true,
956 SpaceState::Never => false,
958 if force_space_before(&t.kind) || needs_space {
963 self.buf.push_str(&pprust::token_to_string(t));
966 fn need_space_prefix(&self) -> bool {
967 if self.result.is_empty() {
971 let last_arg = self.result.last().unwrap();
972 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
973 if ident_like(&self.start_tok) {
976 if self.start_tok.kind == TokenKind::Colon {
981 if force_space_before(&self.start_tok.kind) {
988 /// Returns a collection of parsed macro def's arguments.
989 fn parse(mut self, tokens: TokenStream) -> Option<Vec<ParsedMacroArg>> {
990 let mut iter = tokens.trees();
992 while let Some(tok) = iter.next() {
994 TokenTree::Token(Token {
995 kind: TokenKind::Dollar,
998 // We always want to add a separator before meta variables.
999 if !self.buf.is_empty() {
1000 self.add_separator();
1003 // Start keeping the name of this metavariable in the buffer.
1004 self.is_meta_var = true;
1005 self.lo = span.lo();
1006 self.start_tok = Token {
1007 kind: TokenKind::Dollar,
1011 TokenTree::Token(Token {
1012 kind: TokenKind::Colon,
1014 }) if self.is_meta_var => {
1015 self.add_meta_variable(&mut iter)?;
1017 TokenTree::Token(ref t) => self.update_buffer(t),
1018 TokenTree::Delimited(delimited_span, delimited, ref tts) => {
1019 if !self.buf.is_empty() {
1020 if next_space(&self.last_tok.kind) == SpaceState::Always {
1021 self.add_separator();
1027 // Parse the stuff inside delimiters.
1028 let mut parser = MacroArgParser::new();
1029 parser.lo = delimited_span.open.lo();
1030 let delimited_arg = parser.parse(tts.clone())?;
1032 let span = delimited_span.entire();
1033 if self.is_meta_var {
1034 self.add_repeat(delimited_arg, delimited, &mut iter, span)?;
1035 self.is_meta_var = false;
1037 self.add_delimited(delimited_arg, delimited, span);
1042 self.set_last_tok(&tok);
1045 // We are left with some stuff in the buffer. Since there is nothing
1046 // left to separate, add this as `Other`.
1047 if !self.buf.is_empty() {
1056 context: &RewriteContext<'_>,
1057 args: &[ParsedMacroArg],
1059 ) -> Option<String> {
1060 wrap_macro_args_inner(context, args, shape, false)
1061 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
1064 fn wrap_macro_args_inner(
1065 context: &RewriteContext<'_>,
1066 args: &[ParsedMacroArg],
1068 use_multiple_lines: bool,
1069 ) -> Option<String> {
1070 let mut result = String::with_capacity(128);
1071 let mut iter = args.iter().peekable();
1072 let indent_str = shape.indent.to_string_with_newline(context.config);
1074 while let Some(ref arg) = iter.next() {
1075 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
1077 if use_multiple_lines
1078 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
1080 if arg.kind.ends_with_space() {
1083 result.push_str(&indent_str);
1084 } else if let Some(ref next_arg) = iter.peek() {
1085 let space_before_dollar =
1086 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
1087 let space_before_brace = next_arg.kind.starts_with_brace();
1088 if space_before_dollar || space_before_brace {
1094 if !use_multiple_lines && result.len() >= shape.width {
1101 // This is a bit sketchy. The token rules probably need tweaking, but it works
1102 // for some common cases. I hope the basic logic is sufficient. Note that the
1103 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
1104 // and `(`/`)` have special meaning.
1106 // We always try and format on one line.
1107 // FIXME: Use multi-line when every thing does not fit on one line.
1108 fn format_macro_args(
1109 context: &RewriteContext<'_>,
1110 token_stream: TokenStream,
1112 ) -> Option<String> {
1113 if !context.config.format_macro_matchers() {
1114 let span = span_for_token_stream(&token_stream);
1115 return Some(match span {
1116 Some(span) => context.snippet(span).to_owned(),
1117 None => String::new(),
1120 let parsed_args = MacroArgParser::new().parse(token_stream)?;
1121 wrap_macro_args(context, &parsed_args, shape)
1124 fn span_for_token_stream(token_stream: &TokenStream) -> Option<Span> {
1125 token_stream.trees().next().map(|tt| tt.span())
1128 // We should insert a space if the next token is a:
1129 #[derive(Copy, Clone, PartialEq)]
1133 Ident, // Or ident/literal-like thing.
1137 fn force_space_before(tok: &TokenKind) -> bool {
1138 debug!("tok: force_space_before {:?}", tok);
1152 | TokenKind::BinOpEq(_)
1156 | TokenKind::FatArrow
1157 | TokenKind::BinOp(_)
1159 | TokenKind::Dollar => true,
1164 fn ident_like(tok: &Token) -> bool {
1166 TokenKind::Ident(..) | TokenKind::Literal(..) | TokenKind::Lifetime(_) => true,
1171 fn next_space(tok: &TokenKind) -> SpaceState {
1172 debug!("next_space: {:?}", tok);
1176 | TokenKind::BinOp(BinOpToken::And)
1182 | TokenKind::DotDotDot
1183 | TokenKind::DotDotEq
1184 | TokenKind::Question => SpaceState::Punctuation,
1189 | TokenKind::OpenDelim(_)
1190 | TokenKind::CloseDelim(_) => SpaceState::Never,
1192 TokenKind::Literal(..) | TokenKind::Ident(..) | TokenKind::Lifetime(_) => SpaceState::Ident,
1194 _ => SpaceState::Always,
1198 /// Tries to convert a macro use into a short hand try expression. Returns `None`
1199 /// when the macro is not an instance of `try!` (or parsing the inner expression
1201 pub(crate) fn convert_try_mac(
1203 context: &RewriteContext<'_>,
1204 ) -> Option<ast::Expr> {
1205 let path = &pprust::path_to_string(&mac.path);
1206 if path == "try" || path == "r#try" {
1207 let ts = mac.args.inner_tokens();
1208 let mut parser = build_parser(context, ts.trees());
1211 id: ast::NodeId::root(), // dummy value
1212 kind: ast::ExprKind::Try(parser.parse_expr().ok()?),
1213 span: mac.span(), // incorrect span, but shouldn't matter too much
1214 attrs: ast::AttrVec::new(),
1222 pub(crate) fn macro_style(mac: &ast::MacCall, context: &RewriteContext<'_>) -> DelimToken {
1223 let snippet = context.snippet(mac.span());
1224 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1225 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1226 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1228 if paren_pos < bracket_pos && paren_pos < brace_pos {
1230 } else if bracket_pos < brace_pos {
1237 // A very simple parser that just parses a macros 2.0 definition into its branches.
1238 // Currently we do not attempt to parse any further than that.
1240 struct MacroParser {
1245 // (`(` ... `)` `=>` `{` ... `}`)*
1246 fn parse(&mut self) -> Option<Macro> {
1247 let mut branches = vec![];
1248 while self.toks.look_ahead(1).is_some() {
1249 branches.push(self.parse_branch()?);
1252 Some(Macro { branches })
1255 // `(` ... `)` `=>` `{` ... `}`
1256 fn parse_branch(&mut self) -> Option<MacroBranch> {
1257 let tok = self.toks.next()?;
1258 let (lo, args_paren_kind) = match tok {
1259 TokenTree::Token(..) => return None,
1260 TokenTree::Delimited(delimited_span, d, _) => (delimited_span.open.lo(), d),
1262 let args = TokenStream::new(vec![(tok, Spacing::Joint)]);
1263 match self.toks.next()? {
1264 TokenTree::Token(Token {
1265 kind: TokenKind::FatArrow,
1270 let (mut hi, body, whole_body) = match self.toks.next()? {
1271 TokenTree::Token(..) => return None,
1272 TokenTree::Delimited(delimited_span, ..) => {
1273 let data = delimited_span.entire().data();
1276 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1277 delimited_span.entire(),
1281 if let Some(TokenTree::Token(Token {
1282 kind: TokenKind::Semi,
1284 })) = self.toks.look_ahead(0)
1290 span: mk_sp(lo, hi),
1299 // A parsed macros 2.0 macro definition.
1301 branches: Vec<MacroBranch>,
1304 // FIXME: it would be more efficient to use references to the token streams
1305 // rather than clone them, if we can make the borrowing work out.
1306 struct MacroBranch {
1308 args_paren_kind: DelimToken,
1317 context: &RewriteContext<'_>,
1319 multi_branch_style: bool,
1320 ) -> Option<String> {
1321 // Only attempt to format function-like macros.
1322 if self.args_paren_kind != DelimToken::Paren {
1323 // FIXME(#1539): implement for non-sugared macros.
1328 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1330 if multi_branch_style {
1334 if !context.config.format_macro_bodies() {
1336 result += context.snippet(self.whole_body);
1337 return Some(result);
1340 // The macro body is the most interesting part. It might end up as various
1341 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1342 // parsed as regular Rust code (and note that these can be escaped using
1343 // `$$`). We'll try and format like an AST node, but we'll substitute
1344 // variables for new names with the same length first.
1346 let old_body = context.snippet(self.body).trim();
1347 let (body_str, substs) = replace_names(old_body)?;
1348 let has_block_body = old_body.starts_with('{');
1350 let mut config = context.config.clone();
1351 config.set().hide_parse_errors(true);
1355 let body_indent = if has_block_body {
1358 shape.indent.block_indent(&config)
1360 let new_width = config.max_width() - body_indent.width();
1361 config.set().max_width(new_width);
1363 // First try to format as items, then as statements.
1364 let new_body_snippet = match crate::format_snippet(&body_str, &config, true) {
1365 Some(new_body) => new_body,
1367 let new_width = new_width + config.tab_spaces();
1368 config.set().max_width(new_width);
1369 match crate::format_code_block(&body_str, &config, true) {
1370 Some(new_body) => new_body,
1371 None => return None,
1375 let new_body = wrap_str(
1376 new_body_snippet.snippet.to_string(),
1381 // Indent the body since it is in a block.
1382 let indent_str = body_indent.to_string(&config);
1383 let mut new_body = LineClasses::new(new_body.trim_end())
1386 (String::new(), true),
1387 |(mut s, need_indent), (i, (kind, ref l))| {
1388 if !is_empty_line(l)
1390 && !new_body_snippet.is_line_non_formatted(i + 1)
1394 (s + l + "\n", indent_next_line(kind, &l, &config))
1399 // Undo our replacement of macro variables.
1400 // FIXME: this could be *much* more efficient.
1401 for (old, new) in &substs {
1402 if old_body.find(new).is_some() {
1403 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1406 new_body = new_body.replace(new, old);
1410 result += new_body.trim();
1411 } else if !new_body.is_empty() {
1413 result += &new_body;
1414 result += &shape.indent.to_string(&config);
1423 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1425 /// # Expected syntax
1429 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1430 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1432 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1435 fn format_lazy_static(
1436 context: &RewriteContext<'_>,
1439 ) -> Option<String> {
1440 let mut result = String::with_capacity(1024);
1441 let mut parser = build_parser(context, ts.trees());
1442 let nested_shape = shape
1443 .block_indent(context.config.tab_spaces())
1444 .with_max_width(context.config);
1446 result.push_str("lazy_static! {");
1447 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1449 macro_rules! parse_or {
1450 ($method:ident $(,)* $($arg:expr),* $(,)*) => {
1451 match parser.$method($($arg,)*) {
1453 if parser.sess.span_diagnostic.has_errors() {
1454 parser.sess.span_diagnostic.reset_err_count();
1462 parser.sess.span_diagnostic.reset_err_count();
1469 while parser.token.kind != TokenKind::Eof {
1470 // Parse a `lazy_static!` item.
1471 let vis = crate::utils::format_visibility(
1473 &parse_or!(parse_visibility, rustc_parse::parser::FollowedByType::No),
1475 parser.eat_keyword(kw::Static);
1476 parser.eat_keyword(kw::Ref);
1477 let id = parse_or!(parse_ident);
1478 parser.eat(&TokenKind::Colon);
1479 let ty = parse_or!(parse_ty);
1480 parser.eat(&TokenKind::Eq);
1481 let expr = parse_or!(parse_expr);
1482 parser.eat(&TokenKind::Semi);
1484 // Rewrite as a static item.
1485 let mut stmt = String::with_capacity(128);
1486 stmt.push_str(&format!(
1487 "{}static ref {}: {} =",
1490 ty.rewrite(context, nested_shape)?
1492 result.push_str(&crate::expr::rewrite_assign_rhs(
1496 nested_shape.sub_width(1)?,
1499 if parser.token.kind != TokenKind::Eof {
1500 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1504 result.push_str(&shape.indent.to_string_with_newline(context.config));
1510 fn rewrite_macro_with_items(
1511 context: &RewriteContext<'_>,
1516 position: MacroPosition,
1518 ) -> Option<String> {
1519 let (opener, closer) = match style {
1520 DelimToken::Paren => ("(", ")"),
1521 DelimToken::Bracket => ("[", "]"),
1522 DelimToken::Brace => (" {", "}"),
1525 let trailing_semicolon = match style {
1526 DelimToken::Paren | DelimToken::Bracket if position == MacroPosition::Item => ";",
1530 let mut visitor = FmtVisitor::from_context(context);
1531 visitor.block_indent = shape.indent.block_indent(context.config);
1532 visitor.last_pos = context.snippet_provider.span_after(span, opener.trim());
1534 let item = match item {
1535 MacroArg::Item(item) => item,
1538 visitor.visit_item(&item);
1541 let mut result = String::with_capacity(256);
1542 result.push_str(¯o_name);
1543 result.push_str(opener);
1544 result.push_str(&visitor.block_indent.to_string_with_newline(context.config));
1545 result.push_str(visitor.buffer.trim());
1546 result.push_str(&shape.indent.to_string_with_newline(context.config));
1547 result.push_str(closer);
1548 result.push_str(trailing_semicolon);
1552 const RUST_KW: [Symbol; 59] = [
1606 kw::UnderscoreLifetime,