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 // Return the snippet unmodified if the macro is not block-like
185 Some(context.snippet(span).to_owned())
188 struct InsideMacroGuard<'a> {
189 context: &'a RewriteContext<'a>,
193 impl<'a> InsideMacroGuard<'a> {
194 fn inside_macro_context(context: &'a RewriteContext<'_>) -> InsideMacroGuard<'a> {
195 let is_nested = context.inside_macro.replace(true);
196 InsideMacroGuard { context, is_nested }
200 impl<'a> Drop for InsideMacroGuard<'a> {
202 self.context.inside_macro.replace(self.is_nested);
206 pub(crate) fn rewrite_macro(
208 extra_ident: Option<ast::Ident>,
209 context: &RewriteContext<'_>,
211 position: MacroPosition,
212 ) -> Option<String> {
213 let should_skip = context
215 .skip_macro(&context.snippet(mac.node.path.span).to_owned());
219 let guard = InsideMacroGuard::inside_macro_context(context);
220 let result = catch_unwind(AssertUnwindSafe(|| {
221 rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested)
224 Err(..) | Ok(None) => {
225 context.macro_rewrite_failure.replace(true);
233 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
234 for &keyword in RUST_KW.iter() {
235 if parser.token.is_keyword(keyword)
236 && parser.look_ahead(1, |t| {
237 t.kind == TokenKind::Eof
238 || t.kind == TokenKind::Comma
239 || t.kind == TokenKind::CloseDelim(DelimToken::NoDelim)
244 MacroArg::Keyword(ast::Ident::with_empty_ctxt(keyword), parser.prev_span);
245 return Some(macro_arg);
251 fn rewrite_macro_inner(
253 extra_ident: Option<ast::Ident>,
254 context: &RewriteContext<'_>,
256 position: MacroPosition,
257 is_nested_macro: bool,
258 ) -> Option<String> {
259 if context.config.use_try_shorthand() {
260 if let Some(expr) = convert_try_mac(mac, context) {
261 context.inside_macro.replace(false);
262 return expr.rewrite(context, shape);
266 let original_style = macro_style(mac, context);
268 let macro_name = rewrite_macro_name(context, &mac.node.path, extra_ident);
270 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) && !is_nested_macro {
276 let ts: TokenStream = mac.node.stream();
277 let has_comment = contains_comment(context.snippet(mac.span));
278 if ts.is_empty() && !has_comment {
280 DelimToken::Paren if position == MacroPosition::Item => {
281 Some(format!("{}();", macro_name))
283 DelimToken::Bracket if position == MacroPosition::Item => {
284 Some(format!("{}[];", macro_name))
286 DelimToken::Paren => Some(format!("{}()", macro_name)),
287 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
288 DelimToken::Brace => Some(format!("{} {{}}", macro_name)),
292 // Format well-known macros which cannot be parsed as a valid AST.
293 if macro_name == "lazy_static!" && !has_comment {
294 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
299 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
300 let mut arg_vec = Vec::new();
301 let mut vec_with_semi = false;
302 let mut trailing_comma = false;
304 if DelimToken::Brace != style {
306 if let Some(arg) = parse_macro_arg(&mut parser) {
308 } else if let Some(arg) = check_keyword(&mut parser) {
311 return return_macro_parse_failure_fallback(context, shape.indent, mac.span);
314 match parser.token.kind {
315 TokenKind::Eof => break,
316 TokenKind::Comma => (),
318 // Try to parse `vec![expr; expr]`
319 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
321 if parser.token.kind != TokenKind::Eof {
322 match parse_macro_arg(&mut parser) {
326 if parser.token.kind == TokenKind::Eof && arg_vec.len() == 2 {
327 vec_with_semi = true;
332 return return_macro_parse_failure_fallback(
341 return return_macro_parse_failure_fallback(context, shape.indent, mac.span);
343 _ if arg_vec.last().map_or(false, MacroArg::is_item) => continue,
344 _ => return return_macro_parse_failure_fallback(context, shape.indent, mac.span),
349 if parser.token.kind == TokenKind::Eof {
350 trailing_comma = true;
356 if !arg_vec.is_empty() && arg_vec.iter().all(MacroArg::is_item) {
357 return rewrite_macro_with_items(
369 DelimToken::Paren => {
370 // Handle special case: `vec!(expr; expr)`
372 handle_vec_semi(context, shape, arg_vec, macro_name, style)
374 // Format macro invocation as function call, preserve the trailing
375 // comma because not all macros support them.
376 overflow::rewrite_with_parens(
382 context.config.width_heuristics().fn_call_width,
384 Some(SeparatorTactic::Always)
386 Some(SeparatorTactic::Never)
389 .map(|rw| match position {
390 MacroPosition::Item => format!("{};", rw),
395 DelimToken::Bracket => {
396 // Handle special case: `vec![expr; expr]`
398 handle_vec_semi(context, shape, arg_vec, macro_name, style)
400 // If we are rewriting `vec!` macro or other special macros,
401 // then we can rewrite this as an usual array literal.
402 // Otherwise, we must preserve the original existence of trailing comma.
403 let macro_name = ¯o_name.as_str();
404 let mut force_trailing_comma = if trailing_comma {
405 Some(SeparatorTactic::Always)
407 Some(SeparatorTactic::Never)
409 if FORCED_BRACKET_MACROS.contains(macro_name) && !is_nested_macro {
410 context.inside_macro.replace(false);
411 if context.use_block_indent() {
412 force_trailing_comma = Some(SeparatorTactic::Vertical);
415 let rewrite = rewrite_array(
421 force_trailing_comma,
422 Some(original_style),
424 let comma = match position {
425 MacroPosition::Item => ";",
429 Some(format!("{}{}", rewrite, comma))
432 DelimToken::Brace => {
433 // For macro invocations with braces, always put a space between
434 // the `macro_name!` and `{ /* macro_body */ }` but skip modifying
435 // anything in between the braces (for now).
436 let snippet = context.snippet(mac.span).trim_start_matches(|c| c != '{');
437 match trim_left_preserve_layout(snippet, shape.indent, &context.config) {
438 Some(macro_body) => Some(format!("{} {}", macro_name, macro_body)),
439 None => Some(format!("{} {}", macro_name, snippet)),
447 context: &RewriteContext<'_>,
449 arg_vec: Vec<MacroArg>,
451 delim_token: DelimToken,
452 ) -> Option<String> {
453 let (left, right) = match delim_token {
454 DelimToken::Paren => ("(", ")"),
455 DelimToken::Bracket => ("[", "]"),
459 let mac_shape = shape.offset_left(macro_name.len())?;
460 // 8 = `vec![]` + `; ` or `vec!()` + `; `
461 let total_overhead = 8;
462 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
463 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
464 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
465 if !lhs.contains('\n')
466 && !rhs.contains('\n')
467 && lhs.len() + rhs.len() + total_overhead <= shape.width
469 // macro_name(lhs; rhs) or macro_name[lhs; rhs]
470 Some(format!("{}{}{}; {}{}", macro_name, left, lhs, rhs, right))
472 // macro_name(\nlhs;\nrhs\n) or macro_name[\nlhs;\nrhs\n]
477 nested_shape.indent.to_string_with_newline(context.config),
479 nested_shape.indent.to_string_with_newline(context.config),
481 shape.indent.to_string_with_newline(context.config),
487 pub(crate) fn rewrite_macro_def(
488 context: &RewriteContext<'_>,
493 vis: &ast::Visibility,
495 ) -> Option<String> {
496 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
497 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
501 let mut parser = MacroParser::new(def.stream().into_trees());
502 let parsed_def = match parser.parse() {
504 None => return snippet,
507 let mut result = if def.legacy {
508 String::from("macro_rules!")
510 format!("{}macro", format_visibility(context, vis))
514 result += rewrite_ident(context, ident);
516 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
518 let arm_shape = if multi_branch_style {
520 .block_indent(context.config.tab_spaces())
521 .with_max_width(context.config)
526 let branch_items = itemize_list(
527 context.snippet_provider,
528 parsed_def.branches.iter(),
531 |branch| branch.span.lo(),
532 |branch| branch.span.hi(),
533 |branch| match branch.rewrite(context, arm_shape, multi_branch_style) {
535 // if the rewrite returned None because a macro could not be rewritten, then return the
537 None if *context.macro_rewrite_failure.borrow() => {
538 Some(context.snippet(branch.body).trim().to_string())
542 context.snippet_provider.span_after(span, "{"),
546 .collect::<Vec<_>>();
548 let fmt = ListFormatting::new(arm_shape, context.config)
549 .separator(if def.legacy { ";" } else { "" })
550 .trailing_separator(SeparatorTactic::Always)
551 .preserve_newline(true);
553 if multi_branch_style {
555 result += &arm_shape.indent.to_string_with_newline(context.config);
558 match write_list(&branch_items, &fmt) {
559 Some(ref s) => result += s,
560 None => return snippet,
563 if multi_branch_style {
564 result += &indent.to_string_with_newline(context.config);
571 fn register_metavariable(
572 map: &mut HashMap<String, String>,
577 let mut new_name = "$".repeat(dollar_count - 1);
578 let mut old_name = "$".repeat(dollar_count);
581 new_name.push_str(name);
582 old_name.push_str(name);
584 result.push_str(&new_name);
585 map.insert(old_name, new_name);
588 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
589 // aren't causing problems.
590 // This should also work for escaped `$` variables, where we leave earlier `$`s.
591 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
592 // Each substitution will require five or six extra bytes.
593 let mut result = String::with_capacity(input.len() + 64);
594 let mut substs = HashMap::new();
595 let mut dollar_count = 0;
596 let mut cur_name = String::new();
598 for (kind, c) in CharClasses::new(input.chars()) {
599 if kind != FullCodeCharKind::Normal {
603 } else if dollar_count == 0 {
605 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
606 // Terminates a name following one or more dollars.
607 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
612 } else if c == '(' && cur_name.is_empty() {
613 // FIXME: Support macro def with repeat.
615 } else if c.is_alphanumeric() || c == '_' {
620 if !cur_name.is_empty() {
621 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
624 debug!("replace_names `{}` {:?}", result, substs);
626 Some((result, substs))
629 #[derive(Debug, Clone)]
631 /// e.g., `$x: expr`.
632 MetaVariable(ast::Name, String),
633 /// e.g., `$($foo: expr),*`
635 /// `()`, `[]` or `{}`.
637 /// Inner arguments inside delimiters.
639 /// Something after the closing delimiter and the repeat token, if available.
640 Option<Box<ParsedMacroArg>>,
641 /// The repeat token. This could be one of `*`, `+` or `?`.
644 /// e.g., `[derive(Debug)]`
645 Delimited(DelimToken, Vec<ParsedMacroArg>),
646 /// A possible separator. e.g., `,` or `;`.
647 Separator(String, String),
648 /// Other random stuff that does not fit to other kinds.
649 /// e.g., `== foo` in `($x: expr == foo)`.
650 Other(String, String),
653 fn delim_token_to_str(
654 context: &RewriteContext<'_>,
655 delim_token: DelimToken,
657 use_multiple_lines: bool,
658 inner_is_empty: bool,
659 ) -> (String, String) {
660 let (lhs, rhs) = match delim_token {
661 DelimToken::Paren => ("(", ")"),
662 DelimToken::Bracket => ("[", "]"),
663 DelimToken::Brace => {
664 if inner_is_empty || use_multiple_lines {
670 DelimToken::NoDelim => ("", ""),
672 if use_multiple_lines {
673 let indent_str = shape.indent.to_string_with_newline(context.config);
674 let nested_indent_str = shape
676 .block_indent(context.config)
677 .to_string_with_newline(context.config);
679 format!("{}{}", lhs, nested_indent_str),
680 format!("{}{}", indent_str, rhs),
683 (lhs.to_owned(), rhs.to_owned())
688 fn starts_with_brace(&self) -> bool {
690 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
691 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
696 fn starts_with_dollar(&self) -> bool {
698 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
703 fn ends_with_space(&self) -> bool {
705 MacroArgKind::Separator(..) => true,
710 fn has_meta_var(&self) -> bool {
712 MacroArgKind::MetaVariable(..) => true,
713 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
720 context: &RewriteContext<'_>,
722 use_multiple_lines: bool,
723 ) -> Option<String> {
724 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
725 let inner = wrap_macro_args(context, args, shape)?;
726 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
727 if lhs.len() + inner.len() + rhs.len() <= shape.width {
728 return Some((lhs, inner, rhs));
731 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
732 let nested_shape = shape
733 .block_indent(context.config.tab_spaces())
734 .with_max_width(context.config);
735 let inner = wrap_macro_args(context, args, nested_shape)?;
736 Some((lhs, inner, rhs))
740 MacroArgKind::MetaVariable(ty, ref name) => Some(format!("${}:{}", name, ty)),
741 MacroArgKind::Repeat(delim_tok, ref args, ref another, ref tok) => {
742 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
743 let another = another
745 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
746 .unwrap_or_else(|| "".to_owned());
747 let repeat_tok = pprust::token_to_string(tok);
749 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
751 MacroArgKind::Delimited(delim_tok, ref args) => {
752 rewrite_delimited_inner(delim_tok, args)
753 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
755 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
756 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
761 #[derive(Debug, Clone)]
762 struct ParsedMacroArg {
767 impl ParsedMacroArg {
770 context: &RewriteContext<'_>,
772 use_multiple_lines: bool,
773 ) -> Option<String> {
774 self.kind.rewrite(context, shape, use_multiple_lines)
778 /// Parses macro arguments on macro def.
779 struct MacroArgParser {
780 /// Either a name of the next metavariable, a separator, or junk.
782 /// The start position on the current buffer.
784 /// The first token of the current buffer.
786 /// `true` if we are parsing a metavariable or a repeat.
788 /// The position of the last token.
790 /// The last token parsed.
792 /// Holds the parsed arguments.
793 result: Vec<ParsedMacroArg>,
796 fn last_tok(tt: &TokenTree) -> Token {
798 TokenTree::Token(ref t) => t.clone(),
799 TokenTree::Delimited(delim_span, delim, _) => Token {
800 kind: TokenKind::CloseDelim(delim),
801 span: delim_span.close,
806 impl MacroArgParser {
807 fn new() -> MacroArgParser {
814 kind: TokenKind::Eof,
818 kind: TokenKind::Eof,
825 fn set_last_tok(&mut self, tok: &TokenTree) {
826 self.hi = tok.span().hi();
827 self.last_tok = last_tok(tok);
830 fn add_separator(&mut self) {
831 let prefix = if self.need_space_prefix() {
836 self.result.push(ParsedMacroArg {
837 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
838 span: mk_sp(self.lo, self.hi),
843 fn add_other(&mut self) {
844 let prefix = if self.need_space_prefix() {
849 self.result.push(ParsedMacroArg {
850 kind: MacroArgKind::Other(self.buf.clone(), prefix),
851 span: mk_sp(self.lo, self.hi),
856 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
858 Some(TokenTree::Token(Token {
859 kind: TokenKind::Ident(name, _),
862 self.result.push(ParsedMacroArg {
863 kind: MacroArgKind::MetaVariable(name, self.buf.clone()),
864 span: mk_sp(self.lo, span.hi()),
868 self.is_meta_var = false;
875 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
876 self.result.push(ParsedMacroArg {
877 kind: MacroArgKind::Delimited(delim, inner),
885 inner: Vec<ParsedMacroArg>,
890 let mut buffer = String::new();
891 let mut first = true;
892 let mut lo = span.lo();
893 let mut hi = span.hi();
895 // Parse '*', '+' or '?.
897 self.set_last_tok(&tok);
900 lo = tok.span().lo();
904 TokenTree::Token(Token {
905 kind: TokenKind::BinOp(BinOpToken::Plus),
908 | TokenTree::Token(Token {
909 kind: TokenKind::Question,
912 | TokenTree::Token(Token {
913 kind: TokenKind::BinOp(BinOpToken::Star),
918 TokenTree::Token(ref t) => {
919 buffer.push_str(&pprust::token_to_string(&t));
926 // There could be some random stuff between ')' and '*', '+' or '?'.
927 let another = if buffer.trim().is_empty() {
930 Some(Box::new(ParsedMacroArg {
931 kind: MacroArgKind::Other(buffer, "".to_owned()),
936 self.result.push(ParsedMacroArg {
937 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
938 span: mk_sp(self.lo, self.hi),
943 fn update_buffer(&mut self, t: &Token) {
944 if self.buf.is_empty() {
945 self.lo = t.span.lo();
946 self.start_tok = t.clone();
948 let needs_space = match next_space(&self.last_tok.kind) {
949 SpaceState::Ident => ident_like(t),
950 SpaceState::Punctuation => !ident_like(t),
951 SpaceState::Always => true,
952 SpaceState::Never => false,
954 if force_space_before(&t.kind) || needs_space {
959 self.buf.push_str(&pprust::token_to_string(t));
962 fn need_space_prefix(&self) -> bool {
963 if self.result.is_empty() {
967 let last_arg = self.result.last().unwrap();
968 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
969 if ident_like(&self.start_tok) {
972 if self.start_tok.kind == TokenKind::Colon {
977 if force_space_before(&self.start_tok.kind) {
984 /// Returns a collection of parsed macro def's arguments.
985 fn parse(mut self, tokens: TokenStream) -> Option<Vec<ParsedMacroArg>> {
986 let mut iter = tokens.trees();
988 while let Some(tok) = iter.next() {
990 TokenTree::Token(Token {
991 kind: TokenKind::Dollar,
994 // We always want to add a separator before meta variables.
995 if !self.buf.is_empty() {
996 self.add_separator();
999 // Start keeping the name of this metavariable in the buffer.
1000 self.is_meta_var = true;
1001 self.lo = span.lo();
1002 self.start_tok = Token {
1003 kind: TokenKind::Dollar,
1007 TokenTree::Token(Token {
1008 kind: TokenKind::Colon,
1010 }) if self.is_meta_var => {
1011 self.add_meta_variable(&mut iter)?;
1013 TokenTree::Token(ref t) => self.update_buffer(t),
1014 TokenTree::Delimited(delimited_span, delimited, ref tts) => {
1015 if !self.buf.is_empty() {
1016 if next_space(&self.last_tok.kind) == SpaceState::Always {
1017 self.add_separator();
1023 // Parse the stuff inside delimiters.
1024 let mut parser = MacroArgParser::new();
1025 parser.lo = delimited_span.open.lo();
1026 let delimited_arg = parser.parse(tts.clone())?;
1028 let span = delimited_span.entire();
1029 if self.is_meta_var {
1030 self.add_repeat(delimited_arg, delimited, &mut iter, span)?;
1031 self.is_meta_var = false;
1033 self.add_delimited(delimited_arg, delimited, span);
1038 self.set_last_tok(&tok);
1041 // We are left with some stuff in the buffer. Since there is nothing
1042 // left to separate, add this as `Other`.
1043 if !self.buf.is_empty() {
1052 context: &RewriteContext<'_>,
1053 args: &[ParsedMacroArg],
1055 ) -> Option<String> {
1056 wrap_macro_args_inner(context, args, shape, false)
1057 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
1060 fn wrap_macro_args_inner(
1061 context: &RewriteContext<'_>,
1062 args: &[ParsedMacroArg],
1064 use_multiple_lines: bool,
1065 ) -> Option<String> {
1066 let mut result = String::with_capacity(128);
1067 let mut iter = args.iter().peekable();
1068 let indent_str = shape.indent.to_string_with_newline(context.config);
1070 while let Some(ref arg) = iter.next() {
1071 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
1073 if use_multiple_lines
1074 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
1076 if arg.kind.ends_with_space() {
1079 result.push_str(&indent_str);
1080 } else if let Some(ref next_arg) = iter.peek() {
1081 let space_before_dollar =
1082 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
1083 let space_before_brace = next_arg.kind.starts_with_brace();
1084 if space_before_dollar || space_before_brace {
1090 if !use_multiple_lines && result.len() >= shape.width {
1097 // This is a bit sketchy. The token rules probably need tweaking, but it works
1098 // for some common cases. I hope the basic logic is sufficient. Note that the
1099 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
1100 // and `(`/`)` have special meaning.
1102 // We always try and format on one line.
1103 // FIXME: Use multi-line when every thing does not fit on one line.
1104 fn format_macro_args(
1105 context: &RewriteContext<'_>,
1106 token_stream: TokenStream,
1108 ) -> Option<String> {
1109 if !context.config.format_macro_matchers() {
1110 let span = span_for_token_stream(&token_stream);
1111 return Some(match span {
1112 Some(span) => context.snippet(span).to_owned(),
1113 None => String::new(),
1116 let parsed_args = MacroArgParser::new().parse(token_stream)?;
1117 wrap_macro_args(context, &parsed_args, shape)
1120 fn span_for_token_stream(token_stream: &TokenStream) -> Option<Span> {
1121 token_stream.trees().next().map(|tt| tt.span())
1124 // We should insert a space if the next token is a:
1125 #[derive(Copy, Clone, PartialEq)]
1129 Ident, // Or ident/literal-like thing.
1133 fn force_space_before(tok: &TokenKind) -> bool {
1134 debug!("tok: force_space_before {:?}", tok);
1148 | TokenKind::BinOpEq(_)
1152 | TokenKind::FatArrow
1153 | TokenKind::BinOp(_)
1155 | TokenKind::Dollar => true,
1160 fn ident_like(tok: &Token) -> bool {
1162 TokenKind::Ident(..) | TokenKind::Literal(..) | TokenKind::Lifetime(_) => true,
1167 fn next_space(tok: &TokenKind) -> SpaceState {
1168 debug!("next_space: {:?}", tok);
1172 | TokenKind::BinOp(BinOpToken::And)
1178 | TokenKind::DotDotDot
1179 | TokenKind::DotDotEq
1180 | TokenKind::Question => SpaceState::Punctuation,
1185 | TokenKind::OpenDelim(_)
1186 | TokenKind::CloseDelim(_)
1187 | TokenKind::Whitespace => SpaceState::Never,
1189 TokenKind::Literal(..) | TokenKind::Ident(..) | TokenKind::Lifetime(_) => SpaceState::Ident,
1191 _ => SpaceState::Always,
1195 /// Tries to convert a macro use into a short hand try expression. Returns `None`
1196 /// when the macro is not an instance of `try!` (or parsing the inner expression
1198 pub(crate) fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext<'_>) -> Option<ast::Expr> {
1199 if &mac.node.path.to_string() == "try" {
1200 let ts: TokenStream = mac.node.tts.clone();
1201 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1204 id: ast::NodeId::root(), // dummy value
1205 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1206 span: mac.span, // incorrect span, but shouldn't matter too much
1207 attrs: ThinVec::new(),
1214 fn macro_style(mac: &ast::Mac, context: &RewriteContext<'_>) -> DelimToken {
1215 let snippet = context.snippet(mac.span);
1216 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1217 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1218 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1220 if paren_pos < bracket_pos && paren_pos < brace_pos {
1222 } else if bracket_pos < brace_pos {
1229 // A very simple parser that just parses a macros 2.0 definition into its branches.
1230 // Currently we do not attempt to parse any further than that.
1232 struct MacroParser {
1237 // (`(` ... `)` `=>` `{` ... `}`)*
1238 fn parse(&mut self) -> Option<Macro> {
1239 let mut branches = vec![];
1240 while self.toks.look_ahead(1).is_some() {
1241 branches.push(self.parse_branch()?);
1244 Some(Macro { branches })
1247 // `(` ... `)` `=>` `{` ... `}`
1248 fn parse_branch(&mut self) -> Option<MacroBranch> {
1249 let tok = self.toks.next()?;
1250 let (lo, args_paren_kind) = match tok {
1251 TokenTree::Token(..) => return None,
1252 TokenTree::Delimited(delimited_span, d, _) => (delimited_span.open.lo(), d),
1254 let args = tok.joint();
1255 match self.toks.next()? {
1256 TokenTree::Token(Token {
1257 kind: TokenKind::FatArrow,
1262 let (mut hi, body, whole_body) = match self.toks.next()? {
1263 TokenTree::Token(..) => return None,
1264 TokenTree::Delimited(delimited_span, ..) => {
1265 let data = delimited_span.entire().data();
1268 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1269 delimited_span.entire(),
1273 if let Some(TokenTree::Token(Token {
1274 kind: TokenKind::Semi,
1276 })) = self.toks.look_ahead(0)
1282 span: mk_sp(lo, hi),
1291 // A parsed macros 2.0 macro definition.
1293 branches: Vec<MacroBranch>,
1296 // FIXME: it would be more efficient to use references to the token streams
1297 // rather than clone them, if we can make the borrowing work out.
1298 struct MacroBranch {
1300 args_paren_kind: DelimToken,
1309 context: &RewriteContext<'_>,
1311 multi_branch_style: bool,
1312 ) -> Option<String> {
1313 // Only attempt to format function-like macros.
1314 if self.args_paren_kind != DelimToken::Paren {
1315 // FIXME(#1539): implement for non-sugared macros.
1320 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1322 if multi_branch_style {
1326 if !context.config.format_macro_bodies() {
1328 result += context.snippet(self.whole_body);
1329 return Some(result);
1332 // The macro body is the most interesting part. It might end up as various
1333 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1334 // parsed as regular Rust code (and note that these can be escaped using
1335 // `$$`). We'll try and format like an AST node, but we'll substitute
1336 // variables for new names with the same length first.
1338 let old_body = context.snippet(self.body).trim();
1339 let (body_str, substs) = replace_names(old_body)?;
1340 let has_block_body = old_body.starts_with('{');
1342 let mut config = context.config.clone();
1343 config.set().hide_parse_errors(true);
1347 let body_indent = if has_block_body {
1350 shape.indent.block_indent(&config)
1352 let new_width = config.max_width() - body_indent.width();
1353 config.set().max_width(new_width);
1355 // First try to format as items, then as statements.
1356 let new_body_snippet = match crate::format_snippet(&body_str, &config) {
1357 Some(new_body) => new_body,
1359 let new_width = new_width + config.tab_spaces();
1360 config.set().max_width(new_width);
1361 match crate::format_code_block(&body_str, &config) {
1362 Some(new_body) => new_body,
1363 None => return None,
1367 let new_body = wrap_str(
1368 new_body_snippet.snippet.to_string(),
1373 // Indent the body since it is in a block.
1374 let indent_str = body_indent.to_string(&config);
1375 let mut new_body = LineClasses::new(new_body.trim_end())
1378 (String::new(), true),
1379 |(mut s, need_indent), (i, (kind, ref l))| {
1380 if !is_empty_line(l)
1382 && !new_body_snippet.is_line_non_formatted(i + 1)
1386 (s + l + "\n", indent_next_line(kind, &l, &config))
1391 // Undo our replacement of macro variables.
1392 // FIXME: this could be *much* more efficient.
1393 for (old, new) in &substs {
1394 if old_body.find(new).is_some() {
1395 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1398 new_body = new_body.replace(new, old);
1402 result += new_body.trim();
1403 } else if !new_body.is_empty() {
1405 result += &new_body;
1406 result += &shape.indent.to_string(&config);
1415 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1417 /// # Expected syntax
1421 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1422 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1424 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1427 fn format_lazy_static(
1428 context: &RewriteContext<'_>,
1431 ) -> Option<String> {
1432 let mut result = String::with_capacity(1024);
1433 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1434 let nested_shape = shape
1435 .block_indent(context.config.tab_spaces())
1436 .with_max_width(context.config);
1438 result.push_str("lazy_static! {");
1439 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1441 macro_rules! parse_or {
1442 ($method:ident $(,)* $($arg:expr),* $(,)*) => {
1443 match parser.$method($($arg,)*) {
1445 if parser.sess.span_diagnostic.has_errors() {
1446 parser.sess.span_diagnostic.reset_err_count();
1454 parser.sess.span_diagnostic.reset_err_count();
1461 while parser.token.kind != TokenKind::Eof {
1462 // Parse a `lazy_static!` item.
1463 let vis = crate::utils::format_visibility(context, &parse_or!(parse_visibility, false));
1464 parser.eat_keyword(kw::Static);
1465 parser.eat_keyword(kw::Ref);
1466 let id = parse_or!(parse_ident);
1467 parser.eat(&TokenKind::Colon);
1468 let ty = parse_or!(parse_ty);
1469 parser.eat(&TokenKind::Eq);
1470 let expr = parse_or!(parse_expr);
1471 parser.eat(&TokenKind::Semi);
1473 // Rewrite as a static item.
1474 let mut stmt = String::with_capacity(128);
1475 stmt.push_str(&format!(
1476 "{}static ref {}: {} =",
1479 ty.rewrite(context, nested_shape)?
1481 result.push_str(&crate::expr::rewrite_assign_rhs(
1485 nested_shape.sub_width(1)?,
1488 if parser.token.kind != TokenKind::Eof {
1489 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1493 result.push_str(&shape.indent.to_string_with_newline(context.config));
1499 fn rewrite_macro_with_items(
1500 context: &RewriteContext<'_>,
1505 position: MacroPosition,
1507 ) -> Option<String> {
1508 let (opener, closer) = match style {
1509 DelimToken::Paren => ("(", ")"),
1510 DelimToken::Bracket => ("[", "]"),
1511 DelimToken::Brace => (" {", "}"),
1514 let trailing_semicolon = match style {
1515 DelimToken::Paren | DelimToken::Bracket if position == MacroPosition::Item => ";",
1519 let mut visitor = FmtVisitor::from_context(context);
1520 visitor.block_indent = shape.indent.block_indent(context.config);
1521 visitor.last_pos = context.snippet_provider.span_after(span, opener.trim());
1523 let item = match item {
1524 MacroArg::Item(item) => item,
1527 visitor.visit_item(&item);
1530 let mut result = String::with_capacity(256);
1531 result.push_str(¯o_name);
1532 result.push_str(opener);
1533 result.push_str(&visitor.block_indent.to_string_with_newline(context.config));
1534 result.push_str(visitor.buffer.trim());
1535 result.push_str(&shape.indent.to_string_with_newline(context.config));
1536 result.push_str(closer);
1537 result.push_str(trailing_semicolon);
1541 const RUST_KW: [Symbol; 60] = [
1595 kw::UnderscoreLifetime,