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 syntax::parse::new_parser_from_tts;
16 use syntax::parse::parser::Parser;
17 use syntax::parse::token::{BinOpToken, DelimToken, Token, TokenKind};
18 use syntax::print::pprust;
19 use syntax::source_map::{BytePos, Span};
20 use syntax::symbol::kw;
21 use syntax::tokenstream::{Cursor, TokenStream, TokenTree};
23 use syntax::{ast, parse, ptr};
24 use syntax_pos::{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(ast::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.to_string()),
93 fn parse_macro_arg<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
94 macro_rules! parse_macro_arg {
95 ($macro_arg:ident, $parser:expr, $f:expr) => {
96 let mut cloned_parser = (*parser).clone();
97 match $parser(&mut cloned_parser) {
99 if parser.sess.span_diagnostic.has_errors() {
100 parser.sess.span_diagnostic.reset_err_count();
102 // Parsing succeeded.
103 *parser = cloned_parser;
104 return Some(MacroArg::$macro_arg($f(x)?));
109 parser.sess.span_diagnostic.reset_err_count();
117 |parser: &mut parse::parser::Parser<'b>| parser.parse_expr(),
118 |x: ptr::P<ast::Expr>| Some(x)
122 |parser: &mut parse::parser::Parser<'b>| parser.parse_ty(),
123 |x: ptr::P<ast::Ty>| Some(x)
127 |parser: &mut parse::parser::Parser<'b>| parser.parse_pat(None),
128 |x: ptr::P<ast::Pat>| Some(x)
130 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
133 |parser: &mut parse::parser::Parser<'b>| parser.parse_item(),
134 |x: Option<ptr::P<ast::Item>>| x
140 /// Rewrite macro name without using pretty-printer if possible.
141 fn rewrite_macro_name(
142 context: &RewriteContext<'_>,
144 extra_ident: Option<ast::Ident>,
146 let name = if path.segments.len() == 1 {
147 // Avoid using pretty-printer in the common case.
148 format!("{}!", rewrite_ident(context, path.segments[0].ident))
153 Some(ident) if ident.name != kw::Invalid => format!("{} {}", name, ident),
158 // Use this on failing to format the macro call.
159 fn return_macro_parse_failure_fallback(
160 context: &RewriteContext<'_>,
163 ) -> Option<String> {
164 // Mark this as a failure however we format it
165 context.macro_rewrite_failure.replace(true);
167 // Heuristically determine whether the last line of the macro uses "Block" style
168 // rather than using "Visual" style, or another indentation style.
169 let is_like_block_indent_style = context
173 .map(|closing_line| {
174 closing_line.trim().chars().all(|ch| match ch {
175 '}' | ')' | ']' => true,
180 if is_like_block_indent_style {
181 return trim_left_preserve_layout(context.snippet(span), indent, &context.config);
184 context.skipped_range.borrow_mut().push((
185 context.source_map.lookup_line(span.lo()).unwrap().line,
186 context.source_map.lookup_line(span.hi()).unwrap().line,
189 // Return the snippet unmodified if the macro is not block-like
190 Some(context.snippet(span).to_owned())
193 pub(crate) fn rewrite_macro(
195 extra_ident: Option<ast::Ident>,
196 context: &RewriteContext<'_>,
198 position: MacroPosition,
199 ) -> Option<String> {
200 let should_skip = context
202 .skip_macro(&context.snippet(mac.path.span).to_owned());
206 let guard = context.enter_macro();
207 let result = catch_unwind(AssertUnwindSafe(|| {
218 Err(..) | Ok(None) => {
219 context.macro_rewrite_failure.replace(true);
227 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
228 for &keyword in RUST_KW.iter() {
229 if parser.token.is_keyword(keyword)
230 && parser.look_ahead(1, |t| {
231 t.kind == TokenKind::Eof
232 || t.kind == TokenKind::Comma
233 || t.kind == TokenKind::CloseDelim(DelimToken::NoDelim)
238 MacroArg::Keyword(ast::Ident::with_dummy_span(keyword), parser.prev_span);
239 return Some(macro_arg);
245 fn rewrite_macro_inner(
247 extra_ident: Option<ast::Ident>,
248 context: &RewriteContext<'_>,
250 position: MacroPosition,
251 is_nested_macro: bool,
252 ) -> Option<String> {
253 if context.config.use_try_shorthand() {
254 if let Some(expr) = convert_try_mac(mac, context) {
255 context.leave_macro();
256 return expr.rewrite(context, shape);
260 let original_style = macro_style(mac, context);
262 let macro_name = rewrite_macro_name(context, &mac.path, extra_ident);
264 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) && !is_nested_macro {
270 let ts: TokenStream = mac.stream();
271 let has_comment = contains_comment(context.snippet(mac.span));
272 if ts.is_empty() && !has_comment {
274 DelimToken::Paren if position == MacroPosition::Item => {
275 Some(format!("{}();", macro_name))
277 DelimToken::Bracket if position == MacroPosition::Item => {
278 Some(format!("{}[];", macro_name))
280 DelimToken::Paren => Some(format!("{}()", macro_name)),
281 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
282 DelimToken::Brace => Some(format!("{} {{}}", macro_name)),
286 // Format well-known macros which cannot be parsed as a valid AST.
287 if macro_name == "lazy_static!" && !has_comment {
288 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
293 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
294 let mut arg_vec = Vec::new();
295 let mut vec_with_semi = false;
296 let mut trailing_comma = false;
298 if DelimToken::Brace != style {
300 if let Some(arg) = check_keyword(&mut parser) {
302 } else if let Some(arg) = parse_macro_arg(&mut parser) {
305 return return_macro_parse_failure_fallback(context, shape.indent, mac.span);
308 match parser.token.kind {
309 TokenKind::Eof => break,
310 TokenKind::Comma => (),
312 // Try to parse `vec![expr; expr]`
313 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
315 if parser.token.kind != TokenKind::Eof {
316 match parse_macro_arg(&mut parser) {
320 if parser.token.kind == TokenKind::Eof && arg_vec.len() == 2 {
321 vec_with_semi = true;
326 return return_macro_parse_failure_fallback(
335 return return_macro_parse_failure_fallback(context, shape.indent, mac.span);
337 _ if arg_vec.last().map_or(false, MacroArg::is_item) => continue,
338 _ => return return_macro_parse_failure_fallback(context, shape.indent, mac.span),
343 if parser.token.kind == TokenKind::Eof {
344 trailing_comma = true;
350 if !arg_vec.is_empty() && arg_vec.iter().all(MacroArg::is_item) {
351 return rewrite_macro_with_items(
363 DelimToken::Paren => {
364 // Handle special case: `vec!(expr; expr)`
366 handle_vec_semi(context, shape, arg_vec, macro_name, style)
368 // Format macro invocation as function call, preserve the trailing
369 // comma because not all macros support them.
370 overflow::rewrite_with_parens(
376 context.config.width_heuristics().fn_call_width,
378 Some(SeparatorTactic::Always)
380 Some(SeparatorTactic::Never)
383 .map(|rw| match position {
384 MacroPosition::Item => format!("{};", rw),
389 DelimToken::Bracket => {
390 // Handle special case: `vec![expr; expr]`
392 handle_vec_semi(context, shape, arg_vec, macro_name, style)
394 // If we are rewriting `vec!` macro or other special macros,
395 // then we can rewrite this as an usual array literal.
396 // Otherwise, we must preserve the original existence of trailing comma.
397 let macro_name = ¯o_name.as_str();
398 let mut force_trailing_comma = if trailing_comma {
399 Some(SeparatorTactic::Always)
401 Some(SeparatorTactic::Never)
403 if FORCED_BRACKET_MACROS.contains(macro_name) && !is_nested_macro {
404 context.leave_macro();
405 if context.use_block_indent() {
406 force_trailing_comma = Some(SeparatorTactic::Vertical);
409 let rewrite = rewrite_array(
415 force_trailing_comma,
416 Some(original_style),
418 let comma = match position {
419 MacroPosition::Item => ";",
423 Some(format!("{}{}", rewrite, comma))
426 DelimToken::Brace => {
427 // For macro invocations with braces, always put a space between
428 // the `macro_name!` and `{ /* macro_body */ }` but skip modifying
429 // anything in between the braces (for now).
430 let snippet = context.snippet(mac.span).trim_start_matches(|c| c != '{');
431 match trim_left_preserve_layout(snippet, shape.indent, &context.config) {
432 Some(macro_body) => Some(format!("{} {}", macro_name, macro_body)),
433 None => Some(format!("{} {}", macro_name, snippet)),
441 context: &RewriteContext<'_>,
443 arg_vec: Vec<MacroArg>,
445 delim_token: DelimToken,
446 ) -> Option<String> {
447 let (left, right) = match delim_token {
448 DelimToken::Paren => ("(", ")"),
449 DelimToken::Bracket => ("[", "]"),
453 let mac_shape = shape.offset_left(macro_name.len())?;
454 // 8 = `vec![]` + `; ` or `vec!()` + `; `
455 let total_overhead = 8;
456 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
457 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
458 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
459 if !lhs.contains('\n')
460 && !rhs.contains('\n')
461 && lhs.len() + rhs.len() + total_overhead <= shape.width
463 // macro_name(lhs; rhs) or macro_name[lhs; rhs]
464 Some(format!("{}{}{}; {}{}", macro_name, left, lhs, rhs, right))
466 // macro_name(\nlhs;\nrhs\n) or macro_name[\nlhs;\nrhs\n]
471 nested_shape.indent.to_string_with_newline(context.config),
473 nested_shape.indent.to_string_with_newline(context.config),
475 shape.indent.to_string_with_newline(context.config),
481 pub(crate) fn rewrite_macro_def(
482 context: &RewriteContext<'_>,
487 vis: &ast::Visibility,
489 ) -> Option<String> {
490 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
491 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
495 let mut parser = MacroParser::new(def.stream().into_trees());
496 let parsed_def = match parser.parse() {
498 None => return snippet,
501 let mut result = if def.legacy {
502 String::from("macro_rules!")
504 format!("{}macro", format_visibility(context, vis))
508 result += rewrite_ident(context, ident);
510 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
512 let arm_shape = if multi_branch_style {
514 .block_indent(context.config.tab_spaces())
515 .with_max_width(context.config)
520 let branch_items = itemize_list(
521 context.snippet_provider,
522 parsed_def.branches.iter(),
525 |branch| branch.span.lo(),
526 |branch| branch.span.hi(),
527 |branch| match branch.rewrite(context, arm_shape, multi_branch_style) {
529 // if the rewrite returned None because a macro could not be rewritten, then return the
531 None if *context.macro_rewrite_failure.borrow() => {
532 Some(context.snippet(branch.body).trim().to_string())
536 context.snippet_provider.span_after(span, "{"),
540 .collect::<Vec<_>>();
542 let fmt = ListFormatting::new(arm_shape, context.config)
543 .separator(if def.legacy { ";" } else { "" })
544 .trailing_separator(SeparatorTactic::Always)
545 .preserve_newline(true);
547 if multi_branch_style {
549 result += &arm_shape.indent.to_string_with_newline(context.config);
552 match write_list(&branch_items, &fmt) {
553 Some(ref s) => result += s,
554 None => return snippet,
557 if multi_branch_style {
558 result += &indent.to_string_with_newline(context.config);
565 fn register_metavariable(
566 map: &mut HashMap<String, String>,
571 let mut new_name = "$".repeat(dollar_count - 1);
572 let mut old_name = "$".repeat(dollar_count);
575 new_name.push_str(name);
576 old_name.push_str(name);
578 result.push_str(&new_name);
579 map.insert(old_name, new_name);
582 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
583 // aren't causing problems.
584 // This should also work for escaped `$` variables, where we leave earlier `$`s.
585 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
586 // Each substitution will require five or six extra bytes.
587 let mut result = String::with_capacity(input.len() + 64);
588 let mut substs = HashMap::new();
589 let mut dollar_count = 0;
590 let mut cur_name = String::new();
592 for (kind, c) in CharClasses::new(input.chars()) {
593 if kind != FullCodeCharKind::Normal {
597 } else if dollar_count == 0 {
599 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
600 // Terminates a name following one or more dollars.
601 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
606 } else if c == '(' && cur_name.is_empty() {
607 // FIXME: Support macro def with repeat.
609 } else if c.is_alphanumeric() || c == '_' {
614 if !cur_name.is_empty() {
615 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
618 debug!("replace_names `{}` {:?}", result, substs);
620 Some((result, substs))
623 #[derive(Debug, Clone)]
625 /// e.g., `$x: expr`.
626 MetaVariable(ast::Name, String),
627 /// e.g., `$($foo: expr),*`
629 /// `()`, `[]` or `{}`.
631 /// Inner arguments inside delimiters.
633 /// Something after the closing delimiter and the repeat token, if available.
634 Option<Box<ParsedMacroArg>>,
635 /// The repeat token. This could be one of `*`, `+` or `?`.
638 /// e.g., `[derive(Debug)]`
639 Delimited(DelimToken, Vec<ParsedMacroArg>),
640 /// A possible separator. e.g., `,` or `;`.
641 Separator(String, String),
642 /// Other random stuff that does not fit to other kinds.
643 /// e.g., `== foo` in `($x: expr == foo)`.
644 Other(String, String),
647 fn delim_token_to_str(
648 context: &RewriteContext<'_>,
649 delim_token: DelimToken,
651 use_multiple_lines: bool,
652 inner_is_empty: bool,
653 ) -> (String, String) {
654 let (lhs, rhs) = match delim_token {
655 DelimToken::Paren => ("(", ")"),
656 DelimToken::Bracket => ("[", "]"),
657 DelimToken::Brace => {
658 if inner_is_empty || use_multiple_lines {
664 DelimToken::NoDelim => ("", ""),
666 if use_multiple_lines {
667 let indent_str = shape.indent.to_string_with_newline(context.config);
668 let nested_indent_str = shape
670 .block_indent(context.config)
671 .to_string_with_newline(context.config);
673 format!("{}{}", lhs, nested_indent_str),
674 format!("{}{}", indent_str, rhs),
677 (lhs.to_owned(), rhs.to_owned())
682 fn starts_with_brace(&self) -> bool {
684 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
685 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
690 fn starts_with_dollar(&self) -> bool {
692 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
697 fn ends_with_space(&self) -> bool {
699 MacroArgKind::Separator(..) => true,
704 fn has_meta_var(&self) -> bool {
706 MacroArgKind::MetaVariable(..) => true,
707 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
714 context: &RewriteContext<'_>,
716 use_multiple_lines: bool,
717 ) -> Option<String> {
718 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
719 let inner = wrap_macro_args(context, args, shape)?;
720 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
721 if lhs.len() + inner.len() + rhs.len() <= shape.width {
722 return Some((lhs, inner, rhs));
725 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
726 let nested_shape = shape
727 .block_indent(context.config.tab_spaces())
728 .with_max_width(context.config);
729 let inner = wrap_macro_args(context, args, nested_shape)?;
730 Some((lhs, inner, rhs))
734 MacroArgKind::MetaVariable(ty, ref name) => Some(format!("${}:{}", name, ty)),
735 MacroArgKind::Repeat(delim_tok, ref args, ref another, ref tok) => {
736 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
737 let another = another
739 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
740 .unwrap_or_else(|| "".to_owned());
741 let repeat_tok = pprust::token_to_string(tok);
743 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
745 MacroArgKind::Delimited(delim_tok, ref args) => {
746 rewrite_delimited_inner(delim_tok, args)
747 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
749 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
750 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
755 #[derive(Debug, Clone)]
756 struct ParsedMacroArg {
761 impl ParsedMacroArg {
764 context: &RewriteContext<'_>,
766 use_multiple_lines: bool,
767 ) -> Option<String> {
768 self.kind.rewrite(context, shape, use_multiple_lines)
772 /// Parses macro arguments on macro def.
773 struct MacroArgParser {
774 /// Either a name of the next metavariable, a separator, or junk.
776 /// The start position on the current buffer.
778 /// The first token of the current buffer.
780 /// `true` if we are parsing a metavariable or a repeat.
782 /// The position of the last token.
784 /// The last token parsed.
786 /// Holds the parsed arguments.
787 result: Vec<ParsedMacroArg>,
790 fn last_tok(tt: &TokenTree) -> Token {
792 TokenTree::Token(ref t) => t.clone(),
793 TokenTree::Delimited(delim_span, delim, _) => Token {
794 kind: TokenKind::CloseDelim(delim),
795 span: delim_span.close,
800 impl MacroArgParser {
801 fn new() -> MacroArgParser {
808 kind: TokenKind::Eof,
812 kind: TokenKind::Eof,
819 fn set_last_tok(&mut self, tok: &TokenTree) {
820 self.hi = tok.span().hi();
821 self.last_tok = last_tok(tok);
824 fn add_separator(&mut self) {
825 let prefix = if self.need_space_prefix() {
830 self.result.push(ParsedMacroArg {
831 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
832 span: mk_sp(self.lo, self.hi),
837 fn add_other(&mut self) {
838 let prefix = if self.need_space_prefix() {
843 self.result.push(ParsedMacroArg {
844 kind: MacroArgKind::Other(self.buf.clone(), prefix),
845 span: mk_sp(self.lo, self.hi),
850 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
852 Some(TokenTree::Token(Token {
853 kind: TokenKind::Ident(name, _),
856 self.result.push(ParsedMacroArg {
857 kind: MacroArgKind::MetaVariable(name, self.buf.clone()),
858 span: mk_sp(self.lo, span.hi()),
862 self.is_meta_var = false;
869 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
870 self.result.push(ParsedMacroArg {
871 kind: MacroArgKind::Delimited(delim, inner),
879 inner: Vec<ParsedMacroArg>,
884 let mut buffer = String::new();
885 let mut first = true;
886 let mut lo = span.lo();
887 let mut hi = span.hi();
889 // Parse '*', '+' or '?.
891 self.set_last_tok(&tok);
894 lo = tok.span().lo();
898 TokenTree::Token(Token {
899 kind: TokenKind::BinOp(BinOpToken::Plus),
902 | TokenTree::Token(Token {
903 kind: TokenKind::Question,
906 | TokenTree::Token(Token {
907 kind: TokenKind::BinOp(BinOpToken::Star),
912 TokenTree::Token(ref t) => {
913 buffer.push_str(&pprust::token_to_string(&t));
920 // There could be some random stuff between ')' and '*', '+' or '?'.
921 let another = if buffer.trim().is_empty() {
924 Some(Box::new(ParsedMacroArg {
925 kind: MacroArgKind::Other(buffer, "".to_owned()),
930 self.result.push(ParsedMacroArg {
931 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
932 span: mk_sp(self.lo, self.hi),
937 fn update_buffer(&mut self, t: &Token) {
938 if self.buf.is_empty() {
939 self.lo = t.span.lo();
940 self.start_tok = t.clone();
942 let needs_space = match next_space(&self.last_tok.kind) {
943 SpaceState::Ident => ident_like(t),
944 SpaceState::Punctuation => !ident_like(t),
945 SpaceState::Always => true,
946 SpaceState::Never => false,
948 if force_space_before(&t.kind) || needs_space {
953 self.buf.push_str(&pprust::token_to_string(t));
956 fn need_space_prefix(&self) -> bool {
957 if self.result.is_empty() {
961 let last_arg = self.result.last().unwrap();
962 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
963 if ident_like(&self.start_tok) {
966 if self.start_tok.kind == TokenKind::Colon {
971 if force_space_before(&self.start_tok.kind) {
978 /// Returns a collection of parsed macro def's arguments.
979 fn parse(mut self, tokens: TokenStream) -> Option<Vec<ParsedMacroArg>> {
980 let mut iter = tokens.trees();
982 while let Some(tok) = iter.next() {
984 TokenTree::Token(Token {
985 kind: TokenKind::Dollar,
988 // We always want to add a separator before meta variables.
989 if !self.buf.is_empty() {
990 self.add_separator();
993 // Start keeping the name of this metavariable in the buffer.
994 self.is_meta_var = true;
996 self.start_tok = Token {
997 kind: TokenKind::Dollar,
1001 TokenTree::Token(Token {
1002 kind: TokenKind::Colon,
1004 }) if self.is_meta_var => {
1005 self.add_meta_variable(&mut iter)?;
1007 TokenTree::Token(ref t) => self.update_buffer(t),
1008 TokenTree::Delimited(delimited_span, delimited, ref tts) => {
1009 if !self.buf.is_empty() {
1010 if next_space(&self.last_tok.kind) == SpaceState::Always {
1011 self.add_separator();
1017 // Parse the stuff inside delimiters.
1018 let mut parser = MacroArgParser::new();
1019 parser.lo = delimited_span.open.lo();
1020 let delimited_arg = parser.parse(tts.clone())?;
1022 let span = delimited_span.entire();
1023 if self.is_meta_var {
1024 self.add_repeat(delimited_arg, delimited, &mut iter, span)?;
1025 self.is_meta_var = false;
1027 self.add_delimited(delimited_arg, delimited, span);
1032 self.set_last_tok(&tok);
1035 // We are left with some stuff in the buffer. Since there is nothing
1036 // left to separate, add this as `Other`.
1037 if !self.buf.is_empty() {
1046 context: &RewriteContext<'_>,
1047 args: &[ParsedMacroArg],
1049 ) -> Option<String> {
1050 wrap_macro_args_inner(context, args, shape, false)
1051 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
1054 fn wrap_macro_args_inner(
1055 context: &RewriteContext<'_>,
1056 args: &[ParsedMacroArg],
1058 use_multiple_lines: bool,
1059 ) -> Option<String> {
1060 let mut result = String::with_capacity(128);
1061 let mut iter = args.iter().peekable();
1062 let indent_str = shape.indent.to_string_with_newline(context.config);
1064 while let Some(ref arg) = iter.next() {
1065 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
1067 if use_multiple_lines
1068 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
1070 if arg.kind.ends_with_space() {
1073 result.push_str(&indent_str);
1074 } else if let Some(ref next_arg) = iter.peek() {
1075 let space_before_dollar =
1076 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
1077 let space_before_brace = next_arg.kind.starts_with_brace();
1078 if space_before_dollar || space_before_brace {
1084 if !use_multiple_lines && result.len() >= shape.width {
1091 // This is a bit sketchy. The token rules probably need tweaking, but it works
1092 // for some common cases. I hope the basic logic is sufficient. Note that the
1093 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
1094 // and `(`/`)` have special meaning.
1096 // We always try and format on one line.
1097 // FIXME: Use multi-line when every thing does not fit on one line.
1098 fn format_macro_args(
1099 context: &RewriteContext<'_>,
1100 token_stream: TokenStream,
1102 ) -> Option<String> {
1103 if !context.config.format_macro_matchers() {
1104 let span = span_for_token_stream(&token_stream);
1105 return Some(match span {
1106 Some(span) => context.snippet(span).to_owned(),
1107 None => String::new(),
1110 let parsed_args = MacroArgParser::new().parse(token_stream)?;
1111 wrap_macro_args(context, &parsed_args, shape)
1114 fn span_for_token_stream(token_stream: &TokenStream) -> Option<Span> {
1115 token_stream.trees().next().map(|tt| tt.span())
1118 // We should insert a space if the next token is a:
1119 #[derive(Copy, Clone, PartialEq)]
1123 Ident, // Or ident/literal-like thing.
1127 fn force_space_before(tok: &TokenKind) -> bool {
1128 debug!("tok: force_space_before {:?}", tok);
1142 | TokenKind::BinOpEq(_)
1146 | TokenKind::FatArrow
1147 | TokenKind::BinOp(_)
1149 | TokenKind::Dollar => true,
1154 fn ident_like(tok: &Token) -> bool {
1156 TokenKind::Ident(..) | TokenKind::Literal(..) | TokenKind::Lifetime(_) => true,
1161 fn next_space(tok: &TokenKind) -> SpaceState {
1162 debug!("next_space: {:?}", tok);
1166 | TokenKind::BinOp(BinOpToken::And)
1172 | TokenKind::DotDotDot
1173 | TokenKind::DotDotEq
1174 | TokenKind::Question => SpaceState::Punctuation,
1179 | TokenKind::OpenDelim(_)
1180 | TokenKind::CloseDelim(_)
1181 | TokenKind::Whitespace => SpaceState::Never,
1183 TokenKind::Literal(..) | TokenKind::Ident(..) | TokenKind::Lifetime(_) => SpaceState::Ident,
1185 _ => SpaceState::Always,
1189 /// Tries to convert a macro use into a short hand try expression. Returns `None`
1190 /// when the macro is not an instance of `try!` (or parsing the inner expression
1192 pub(crate) fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext<'_>) -> Option<ast::Expr> {
1193 if &mac.path.to_string() == "try" {
1194 let ts: TokenStream = mac.tts.clone();
1195 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1198 id: ast::NodeId::root(), // dummy value
1199 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1200 span: mac.span, // incorrect span, but shouldn't matter too much
1201 attrs: ThinVec::new(),
1208 fn macro_style(mac: &ast::Mac, context: &RewriteContext<'_>) -> DelimToken {
1209 let snippet = context.snippet(mac.span);
1210 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1211 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1212 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1214 if paren_pos < bracket_pos && paren_pos < brace_pos {
1216 } else if bracket_pos < brace_pos {
1223 // A very simple parser that just parses a macros 2.0 definition into its branches.
1224 // Currently we do not attempt to parse any further than that.
1226 struct MacroParser {
1231 // (`(` ... `)` `=>` `{` ... `}`)*
1232 fn parse(&mut self) -> Option<Macro> {
1233 let mut branches = vec![];
1234 while self.toks.look_ahead(1).is_some() {
1235 branches.push(self.parse_branch()?);
1238 Some(Macro { branches })
1241 // `(` ... `)` `=>` `{` ... `}`
1242 fn parse_branch(&mut self) -> Option<MacroBranch> {
1243 let tok = self.toks.next()?;
1244 let (lo, args_paren_kind) = match tok {
1245 TokenTree::Token(..) => return None,
1246 TokenTree::Delimited(delimited_span, d, _) => (delimited_span.open.lo(), d),
1248 let args = tok.joint();
1249 match self.toks.next()? {
1250 TokenTree::Token(Token {
1251 kind: TokenKind::FatArrow,
1256 let (mut hi, body, whole_body) = match self.toks.next()? {
1257 TokenTree::Token(..) => return None,
1258 TokenTree::Delimited(delimited_span, ..) => {
1259 let data = delimited_span.entire().data();
1262 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1263 delimited_span.entire(),
1267 if let Some(TokenTree::Token(Token {
1268 kind: TokenKind::Semi,
1270 })) = self.toks.look_ahead(0)
1276 span: mk_sp(lo, hi),
1285 // A parsed macros 2.0 macro definition.
1287 branches: Vec<MacroBranch>,
1290 // FIXME: it would be more efficient to use references to the token streams
1291 // rather than clone them, if we can make the borrowing work out.
1292 struct MacroBranch {
1294 args_paren_kind: DelimToken,
1303 context: &RewriteContext<'_>,
1305 multi_branch_style: bool,
1306 ) -> Option<String> {
1307 // Only attempt to format function-like macros.
1308 if self.args_paren_kind != DelimToken::Paren {
1309 // FIXME(#1539): implement for non-sugared macros.
1314 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1316 if multi_branch_style {
1320 if !context.config.format_macro_bodies() {
1322 result += context.snippet(self.whole_body);
1323 return Some(result);
1326 // The macro body is the most interesting part. It might end up as various
1327 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1328 // parsed as regular Rust code (and note that these can be escaped using
1329 // `$$`). We'll try and format like an AST node, but we'll substitute
1330 // variables for new names with the same length first.
1332 let old_body = context.snippet(self.body).trim();
1333 let (body_str, substs) = replace_names(old_body)?;
1334 let has_block_body = old_body.starts_with('{');
1336 let mut config = context.config.clone();
1337 config.set().hide_parse_errors(true);
1341 let body_indent = if has_block_body {
1344 shape.indent.block_indent(&config)
1346 let new_width = config.max_width() - body_indent.width();
1347 config.set().max_width(new_width);
1349 // First try to format as items, then as statements.
1350 let new_body_snippet = match crate::format_snippet(&body_str, &config) {
1351 Some(new_body) => new_body,
1353 let new_width = new_width + config.tab_spaces();
1354 config.set().max_width(new_width);
1355 match crate::format_code_block(&body_str, &config) {
1356 Some(new_body) => new_body,
1357 None => return None,
1361 let new_body = wrap_str(
1362 new_body_snippet.snippet.to_string(),
1367 // Indent the body since it is in a block.
1368 let indent_str = body_indent.to_string(&config);
1369 let mut new_body = LineClasses::new(new_body.trim_end())
1372 (String::new(), true),
1373 |(mut s, need_indent), (i, (kind, ref l))| {
1374 if !is_empty_line(l)
1376 && !new_body_snippet.is_line_non_formatted(i + 1)
1380 (s + l + "\n", indent_next_line(kind, &l, &config))
1385 // Undo our replacement of macro variables.
1386 // FIXME: this could be *much* more efficient.
1387 for (old, new) in &substs {
1388 if old_body.find(new).is_some() {
1389 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1392 new_body = new_body.replace(new, old);
1396 result += new_body.trim();
1397 } else if !new_body.is_empty() {
1399 result += &new_body;
1400 result += &shape.indent.to_string(&config);
1409 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1411 /// # Expected syntax
1415 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1416 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1418 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1421 fn format_lazy_static(
1422 context: &RewriteContext<'_>,
1425 ) -> Option<String> {
1426 let mut result = String::with_capacity(1024);
1427 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1428 let nested_shape = shape
1429 .block_indent(context.config.tab_spaces())
1430 .with_max_width(context.config);
1432 result.push_str("lazy_static! {");
1433 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1435 macro_rules! parse_or {
1436 ($method:ident $(,)* $($arg:expr),* $(,)*) => {
1437 match parser.$method($($arg,)*) {
1439 if parser.sess.span_diagnostic.has_errors() {
1440 parser.sess.span_diagnostic.reset_err_count();
1448 parser.sess.span_diagnostic.reset_err_count();
1455 while parser.token.kind != TokenKind::Eof {
1456 // Parse a `lazy_static!` item.
1457 let vis = crate::utils::format_visibility(context, &parse_or!(parse_visibility, false));
1458 parser.eat_keyword(kw::Static);
1459 parser.eat_keyword(kw::Ref);
1460 let id = parse_or!(parse_ident);
1461 parser.eat(&TokenKind::Colon);
1462 let ty = parse_or!(parse_ty);
1463 parser.eat(&TokenKind::Eq);
1464 let expr = parse_or!(parse_expr);
1465 parser.eat(&TokenKind::Semi);
1467 // Rewrite as a static item.
1468 let mut stmt = String::with_capacity(128);
1469 stmt.push_str(&format!(
1470 "{}static ref {}: {} =",
1473 ty.rewrite(context, nested_shape)?
1475 result.push_str(&crate::expr::rewrite_assign_rhs(
1479 nested_shape.sub_width(1)?,
1482 if parser.token.kind != TokenKind::Eof {
1483 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1487 result.push_str(&shape.indent.to_string_with_newline(context.config));
1493 fn rewrite_macro_with_items(
1494 context: &RewriteContext<'_>,
1499 position: MacroPosition,
1501 ) -> Option<String> {
1502 let (opener, closer) = match style {
1503 DelimToken::Paren => ("(", ")"),
1504 DelimToken::Bracket => ("[", "]"),
1505 DelimToken::Brace => (" {", "}"),
1508 let trailing_semicolon = match style {
1509 DelimToken::Paren | DelimToken::Bracket if position == MacroPosition::Item => ";",
1513 let mut visitor = FmtVisitor::from_context(context);
1514 visitor.block_indent = shape.indent.block_indent(context.config);
1515 visitor.last_pos = context.snippet_provider.span_after(span, opener.trim());
1517 let item = match item {
1518 MacroArg::Item(item) => item,
1521 visitor.visit_item(&item);
1524 let mut result = String::with_capacity(256);
1525 result.push_str(¯o_name);
1526 result.push_str(opener);
1527 result.push_str(&visitor.block_indent.to_string_with_newline(context.config));
1528 result.push_str(visitor.buffer.trim());
1529 result.push_str(&shape.indent.to_string_with_newline(context.config));
1530 result.push_str(closer);
1531 result.push_str(trailing_semicolon);
1535 const RUST_KW: [Symbol; 59] = [
1589 kw::UnderscoreLifetime,