1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // Format list-like macro invocations. These are invocations whose token trees
12 // can be interpreted as expressions and separated by commas.
13 // Note that these token trees do not actually have to be interpreted as
14 // expressions by the compiler. An example of an invocation we would reformat is
15 // foo!( x, y, z ). The token x may represent an identifier in the code, but we
16 // interpreted as an expression.
17 // Macro uses which are not-list like, such as bar!(key => val), will not be
19 // List-like invocations with parentheses will be formatted as function calls,
20 // and those with brackets will be formatted as array literals.
22 use std::collections::HashMap;
25 use syntax::codemap::{BytePos, Span};
26 use syntax::parse::new_parser_from_tts;
27 use syntax::parse::parser::Parser;
28 use syntax::parse::token::{BinOpToken, DelimToken, Token};
29 use syntax::print::pprust;
31 use syntax::tokenstream::{Cursor, ThinTokenStream, TokenStream, TokenTree};
32 use syntax::util::ThinVec;
33 use syntax::{ast, ptr};
35 use codemap::SpanUtils;
37 contains_comment, remove_trailing_white_spaces, CharClasses, FindUncommented, FullCodeCharKind,
40 use expr::rewrite_array;
41 use lists::{itemize_list, write_list, ListFormatting};
43 use rewrite::{Rewrite, RewriteContext};
44 use shape::{Indent, Shape};
46 use utils::{format_visibility, mk_sp, rewrite_ident, wrap_str};
48 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
50 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
51 pub enum MacroPosition {
60 Expr(ptr::P<ast::Expr>),
62 Pat(ptr::P<ast::Pat>),
63 Item(ptr::P<ast::Item>),
66 impl Rewrite for ast::Item {
67 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
68 let mut visitor = ::visitor::FmtVisitor::from_context(context);
69 visitor.block_indent = shape.indent;
70 visitor.last_pos = self.span().lo();
71 visitor.visit_item(self);
76 impl Rewrite for MacroArg {
77 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
79 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
80 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
81 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
82 MacroArg::Item(ref item) => item.rewrite(context, shape),
87 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
88 macro_rules! parse_macro_arg {
89 ($macro_arg:ident, $parser:ident, $f:expr) => {
90 let mut cloned_parser = (*parser).clone();
91 match cloned_parser.$parser() {
93 if parser.sess.span_diagnostic.has_errors() {
94 parser.sess.span_diagnostic.reset_err_count();
97 *parser = cloned_parser;
98 return Some(MacroArg::$macro_arg($f(x)?));
103 parser.sess.span_diagnostic.reset_err_count();
109 parse_macro_arg!(Expr, parse_expr, |x: ptr::P<ast::Expr>| Some(x));
110 parse_macro_arg!(Ty, parse_ty, |x: ptr::P<ast::Ty>| Some(x));
111 parse_macro_arg!(Pat, parse_pat, |x: ptr::P<ast::Pat>| Some(x));
112 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
113 parse_macro_arg!(Item, parse_item, |x: Option<ptr::P<ast::Item>>| x);
118 /// Rewrite macro name without using pretty-printer if possible.
119 fn rewrite_macro_name(
120 context: &RewriteContext,
122 extra_ident: Option<ast::Ident>,
124 let name = if path.segments.len() == 1 {
125 // Avoid using pretty-printer in the common case.
126 format!("{}!", rewrite_ident(context, path.segments[0].ident))
131 Some(ident) if ident != symbol::keywords::Invalid.ident() => format!("{} {}", name, ident),
136 // Use this on failing to format the macro call.
137 fn return_original_snippet_with_failure_marked(
138 context: &RewriteContext,
140 ) -> Option<String> {
141 context.macro_rewrite_failure.replace(true);
142 Some(context.snippet(span).to_owned())
145 pub fn rewrite_macro(
147 extra_ident: Option<ast::Ident>,
148 context: &RewriteContext,
150 position: MacroPosition,
151 ) -> Option<String> {
152 context.inside_macro.replace(true);
153 let result = rewrite_macro_inner(mac, extra_ident, context, shape, position);
154 if result.is_none() {
155 context.macro_rewrite_failure.replace(true);
157 context.inside_macro.replace(false);
161 pub fn rewrite_macro_inner(
163 extra_ident: Option<ast::Ident>,
164 context: &RewriteContext,
166 position: MacroPosition,
167 ) -> Option<String> {
168 if context.config.use_try_shorthand() {
169 if let Some(expr) = convert_try_mac(mac, context) {
170 context.inside_macro.replace(false);
171 return expr.rewrite(context, shape);
175 let original_style = macro_style(mac, context);
177 let macro_name = rewrite_macro_name(context, &mac.node.path, extra_ident);
179 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
185 let ts: TokenStream = mac.node.stream();
186 let has_comment = contains_comment(context.snippet(mac.span));
187 if ts.is_empty() && !has_comment {
189 DelimToken::Paren if position == MacroPosition::Item => {
190 Some(format!("{}();", macro_name))
192 DelimToken::Paren => Some(format!("{}()", macro_name)),
193 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
194 DelimToken::Brace => Some(format!("{}{{}}", macro_name)),
198 // Format well-known macros which cannot be parsed as a valid AST.
199 if macro_name == "lazy_static!" && !has_comment {
200 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
205 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
206 let mut arg_vec = Vec::new();
207 let mut vec_with_semi = false;
208 let mut trailing_comma = false;
210 if DelimToken::Brace != style {
212 match parse_macro_arg(&mut parser) {
213 Some(arg) => arg_vec.push(arg),
214 None => return return_original_snippet_with_failure_marked(context, mac.span),
221 // Try to parse `vec![expr; expr]`
222 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
224 if parser.token != Token::Eof {
225 match parse_macro_arg(&mut parser) {
229 if parser.token == Token::Eof && arg_vec.len() == 2 {
230 vec_with_semi = true;
235 return return_original_snippet_with_failure_marked(
242 return return_original_snippet_with_failure_marked(context, mac.span);
244 _ => return return_original_snippet_with_failure_marked(context, mac.span),
249 if parser.token == Token::Eof {
250 trailing_comma = true;
257 DelimToken::Paren => {
258 // Format macro invocation as function call, preserve the trailing
259 // comma because not all macros support them.
260 overflow::rewrite_with_parens(
263 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>(),
266 context.config.width_heuristics().fn_call_width,
268 Some(SeparatorTactic::Always)
270 Some(SeparatorTactic::Never)
272 ).map(|rw| match position {
273 MacroPosition::Item => format!("{};", rw),
277 DelimToken::Bracket => {
278 // Handle special case: `vec![expr; expr]`
280 let mac_shape = shape.offset_left(macro_name.len())?;
281 // 8 = `vec![]` + `; `
282 let total_overhead = 8;
283 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
284 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
285 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
286 if !lhs.contains('\n')
287 && !rhs.contains('\n')
288 && lhs.len() + rhs.len() + total_overhead <= shape.width
290 Some(format!("{}[{}; {}]", macro_name, lhs, rhs))
295 nested_shape.indent.to_string_with_newline(context.config),
297 nested_shape.indent.to_string_with_newline(context.config),
299 shape.indent.to_string_with_newline(context.config),
303 // If we are rewriting `vec!` macro or other special macros,
304 // then we can rewrite this as an usual array literal.
305 // Otherwise, we must preserve the original existence of trailing comma.
306 let macro_name = ¯o_name.as_str();
307 let mut force_trailing_comma = if trailing_comma {
308 Some(SeparatorTactic::Always)
310 Some(SeparatorTactic::Never)
312 if FORCED_BRACKET_MACROS.contains(macro_name) {
313 context.inside_macro.replace(false);
314 if context.use_block_indent() {
315 force_trailing_comma = Some(SeparatorTactic::Vertical);
318 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
319 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>();
320 let rewrite = rewrite_array(
326 force_trailing_comma,
327 Some(original_style),
329 let comma = match position {
330 MacroPosition::Item => ";",
334 Some(format!("{}{}", rewrite, comma))
337 DelimToken::Brace => {
338 // Skip macro invocations with braces, for now.
339 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
345 pub fn rewrite_macro_def(
346 context: &RewriteContext,
351 vis: &ast::Visibility,
353 ) -> Option<String> {
354 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
355 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
359 let mut parser = MacroParser::new(def.stream().into_trees());
360 let parsed_def = match parser.parse() {
362 None => return snippet,
365 let mut result = if def.legacy {
366 String::from("macro_rules!")
368 format!("{}macro", format_visibility(context, vis))
372 result += rewrite_ident(context, ident);
374 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
376 let arm_shape = if multi_branch_style {
378 .block_indent(context.config.tab_spaces())
379 .with_max_width(context.config)
384 let branch_items = itemize_list(
385 context.snippet_provider,
386 parsed_def.branches.iter(),
389 |branch| branch.span.lo(),
390 |branch| branch.span.hi(),
391 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
392 context.snippet_provider.span_after(span, "{"),
395 ).collect::<Vec<_>>();
397 let fmt = ListFormatting {
398 tactic: DefinitiveListTactic::Vertical,
399 separator: if def.legacy { ";" } else { "" },
400 trailing_separator: SeparatorTactic::Always,
401 separator_place: SeparatorPlace::Back,
403 ends_with_newline: true,
404 preserve_newline: true,
406 config: context.config,
409 if multi_branch_style {
411 result += &arm_shape.indent.to_string_with_newline(context.config);
414 match write_list(&branch_items, &fmt) {
415 Some(ref s) => result += s,
416 None => return snippet,
419 if multi_branch_style {
420 result += &indent.to_string_with_newline(context.config);
427 fn register_metavariable(
428 map: &mut HashMap<String, String>,
433 let mut new_name = String::new();
434 let mut old_name = String::new();
437 for _ in 0..(dollar_count - 1) {
442 new_name.push_str(&name);
443 old_name.push_str(&name);
445 result.push_str(&new_name);
446 map.insert(old_name, new_name);
449 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
450 // aren't causing problems.
451 // This should also work for escaped `$` variables, where we leave earlier `$`s.
452 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
453 // Each substitution will require five or six extra bytes.
454 let mut result = String::with_capacity(input.len() + 64);
455 let mut substs = HashMap::new();
456 let mut dollar_count = 0;
457 let mut cur_name = String::new();
459 for (kind, c) in CharClasses::new(input.chars()) {
460 if kind != FullCodeCharKind::Normal {
464 } else if dollar_count == 0 {
466 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
467 // Terminates a name following one or more dollars.
468 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
473 } else if c == '(' && cur_name.is_empty() {
474 // FIXME: Support macro def with repeat.
476 } else if c.is_alphanumeric() || c == '_' {
481 if !cur_name.is_empty() {
482 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
485 debug!("replace_names `{}` {:?}", result, substs);
487 Some((result, substs))
490 #[derive(Debug, Clone)]
493 MetaVariable(ast::Ident, String),
494 /// e.g. `$($foo: expr),*`
496 /// `()`, `[]` or `{}`.
498 /// Inner arguments inside delimiters.
500 /// Something after the closing delimiter and the repeat token, if available.
501 Option<Box<ParsedMacroArg>>,
502 /// The repeat token. This could be one of `*`, `+` or `?`.
505 /// e.g. `[derive(Debug)]`
506 Delimited(DelimToken, Vec<ParsedMacroArg>),
507 /// A possible separator. e.g. `,` or `;`.
508 Separator(String, String),
509 /// Other random stuff that does not fit to other kinds.
510 /// e.g. `== foo` in `($x: expr == foo)`.
511 Other(String, String),
514 fn delim_token_to_str(
515 context: &RewriteContext,
516 delim_token: &DelimToken,
518 use_multiple_lines: bool,
519 inner_is_empty: bool,
520 ) -> (String, String) {
521 let (lhs, rhs) = match *delim_token {
522 DelimToken::Paren => ("(", ")"),
523 DelimToken::Bracket => ("[", "]"),
524 DelimToken::Brace => {
525 if inner_is_empty || use_multiple_lines {
531 DelimToken::NoDelim => ("", ""),
533 if use_multiple_lines {
534 let indent_str = shape.indent.to_string_with_newline(context.config);
535 let nested_indent_str = shape
537 .block_indent(context.config)
538 .to_string_with_newline(context.config);
540 format!("{}{}", lhs, nested_indent_str),
541 format!("{}{}", indent_str, rhs),
544 (lhs.to_owned(), rhs.to_owned())
549 fn starts_with_brace(&self) -> bool {
551 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
552 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
557 fn starts_with_dollar(&self) -> bool {
559 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
564 fn ends_with_space(&self) -> bool {
566 MacroArgKind::Separator(..) => true,
571 fn has_meta_var(&self) -> bool {
573 MacroArgKind::MetaVariable(..) => true,
574 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
581 context: &RewriteContext,
583 use_multiple_lines: bool,
584 ) -> Option<String> {
585 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
586 let inner = wrap_macro_args(context, args, shape)?;
587 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
588 if lhs.len() + inner.len() + rhs.len() <= shape.width {
589 return Some((lhs, inner, rhs));
592 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
593 let nested_shape = shape
594 .block_indent(context.config.tab_spaces())
595 .with_max_width(context.config);
596 let inner = wrap_macro_args(context, args, nested_shape)?;
597 Some((lhs, inner, rhs))
601 MacroArgKind::MetaVariable(ty, ref name) => {
602 Some(format!("${}:{}", name, ty.name.as_str()))
604 MacroArgKind::Repeat(ref delim_tok, ref args, ref another, ref tok) => {
605 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
606 let another = another
608 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
609 .unwrap_or_else(|| "".to_owned());
610 let repeat_tok = pprust::token_to_string(tok);
612 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
614 MacroArgKind::Delimited(ref delim_tok, ref args) => {
615 rewrite_delimited_inner(delim_tok, args)
616 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
618 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
619 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
624 #[derive(Debug, Clone)]
625 struct ParsedMacroArg {
630 impl ParsedMacroArg {
633 context: &RewriteContext,
635 use_multiple_lines: bool,
636 ) -> Option<String> {
637 self.kind.rewrite(context, shape, use_multiple_lines)
641 /// Parses macro arguments on macro def.
642 struct MacroArgParser {
643 /// Holds either a name of the next metavariable, a separator or a junk.
645 /// The start position on the current buffer.
647 /// The first token of the current buffer.
649 /// Set to true if we are parsing a metavariable or a repeat.
651 /// The position of the last token.
653 /// The last token parsed.
655 /// Holds the parsed arguments.
656 result: Vec<ParsedMacroArg>,
659 fn last_tok(tt: &TokenTree) -> Token {
661 TokenTree::Token(_, ref t) => t.clone(),
662 TokenTree::Delimited(_, ref d) => d.close_token(),
666 impl MacroArgParser {
667 pub fn new() -> MacroArgParser {
673 last_tok: Token::Eof,
674 start_tok: Token::Eof,
679 fn set_last_tok(&mut self, tok: &TokenTree) {
680 self.hi = tok.span().hi();
681 self.last_tok = last_tok(tok);
684 fn add_separator(&mut self) {
685 let prefix = if self.need_space_prefix() {
690 self.result.push(ParsedMacroArg {
691 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
692 span: mk_sp(self.lo, self.hi),
697 fn add_other(&mut self) {
698 let prefix = if self.need_space_prefix() {
703 self.result.push(ParsedMacroArg {
704 kind: MacroArgKind::Other(self.buf.clone(), prefix),
705 span: mk_sp(self.lo, self.hi),
710 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
712 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
713 self.result.push(ParsedMacroArg {
714 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
715 span: mk_sp(self.lo, sp.hi()),
719 self.is_meta_var = false;
726 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
727 self.result.push(ParsedMacroArg {
728 kind: MacroArgKind::Delimited(delim, inner),
736 inner: Vec<ParsedMacroArg>,
741 let mut buffer = String::new();
742 let mut first = false;
743 let mut lo = span.lo();
744 let mut hi = span.hi();
746 // Parse '*', '+' or '?.
747 for ref tok in iter {
748 self.set_last_tok(tok);
751 lo = tok.span().lo();
755 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
756 | TokenTree::Token(_, Token::Question)
757 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
760 TokenTree::Token(sp, ref t) => {
761 buffer.push_str(&pprust::token_to_string(t));
768 // There could be some random stuff between ')' and '*', '+' or '?'.
769 let another = if buffer.trim().is_empty() {
772 Some(Box::new(ParsedMacroArg {
773 kind: MacroArgKind::Other(buffer, "".to_owned()),
778 self.result.push(ParsedMacroArg {
779 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
780 span: mk_sp(self.lo, self.hi),
785 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
786 if self.buf.is_empty() {
788 self.start_tok = t.clone();
790 let needs_space = match next_space(&self.last_tok) {
791 SpaceState::Ident => ident_like(t),
792 SpaceState::Punctuation => !ident_like(t),
793 SpaceState::Always => true,
794 SpaceState::Never => false,
796 if force_space_before(t) || needs_space {
801 self.buf.push_str(&pprust::token_to_string(t));
804 fn need_space_prefix(&self) -> bool {
805 if self.result.is_empty() {
809 let last_arg = self.result.last().unwrap();
810 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
811 if ident_like(&self.start_tok) {
814 if self.start_tok == Token::Colon {
819 if force_space_before(&self.start_tok) {
826 /// Returns a collection of parsed macro def's arguments.
827 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
828 let mut iter = (tokens.into(): TokenStream).trees();
830 while let Some(ref tok) = iter.next() {
832 TokenTree::Token(sp, Token::Dollar) => {
833 // We always want to add a separator before meta variables.
834 if !self.buf.is_empty() {
835 self.add_separator();
838 // Start keeping the name of this metavariable in the buffer.
839 self.is_meta_var = true;
841 self.start_tok = Token::Dollar;
843 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
844 self.add_meta_variable(&mut iter)?;
846 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
847 TokenTree::Delimited(sp, delimited) => {
848 if !self.buf.is_empty() {
849 if next_space(&self.last_tok) == SpaceState::Always {
850 self.add_separator();
856 // Parse the stuff inside delimiters.
857 let mut parser = MacroArgParser::new();
859 let delimited_arg = parser.parse(delimited.tts.clone())?;
861 if self.is_meta_var {
862 self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp)?;
863 self.is_meta_var = false;
865 self.add_delimited(delimited_arg, delimited.delim, *sp);
870 self.set_last_tok(tok);
873 // We are left with some stuff in the buffer. Since there is nothing
874 // left to separate, add this as `Other`.
875 if !self.buf.is_empty() {
884 context: &RewriteContext,
885 args: &[ParsedMacroArg],
887 ) -> Option<String> {
888 wrap_macro_args_inner(context, args, shape, false)
889 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
892 fn wrap_macro_args_inner(
893 context: &RewriteContext,
894 args: &[ParsedMacroArg],
896 use_multiple_lines: bool,
897 ) -> Option<String> {
898 let mut result = String::with_capacity(128);
899 let mut iter = args.iter().peekable();
900 let indent_str = shape.indent.to_string_with_newline(context.config);
902 while let Some(ref arg) = iter.next() {
903 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
905 if use_multiple_lines
906 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
908 if arg.kind.ends_with_space() {
911 result.push_str(&indent_str);
912 } else if let Some(ref next_arg) = iter.peek() {
913 let space_before_dollar =
914 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
915 let space_before_brace = next_arg.kind.starts_with_brace();
916 if space_before_dollar || space_before_brace {
922 if !use_multiple_lines && result.len() >= shape.width {
929 // This is a bit sketchy. The token rules probably need tweaking, but it works
930 // for some common cases. I hope the basic logic is sufficient. Note that the
931 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
932 // and `(`/`)` have special meaning.
934 // We always try and format on one line.
935 // FIXME: Use multi-line when every thing does not fit on one line.
936 fn format_macro_args(
937 context: &RewriteContext,
938 toks: ThinTokenStream,
940 ) -> Option<String> {
941 if !context.config.format_macro_matchers() {
942 let token_stream: TokenStream = toks.into();
943 let span = span_for_token_stream(token_stream);
944 return Some(match span {
945 Some(span) => context.snippet(span).to_owned(),
946 None => String::new(),
949 let parsed_args = MacroArgParser::new().parse(toks)?;
950 wrap_macro_args(context, &parsed_args, shape)
953 fn span_for_token_stream(token_stream: TokenStream) -> Option<Span> {
954 token_stream.trees().next().map(|tt| tt.span())
957 // We should insert a space if the next token is a:
958 #[derive(Copy, Clone, PartialEq)]
962 Ident, // Or ident/literal-like thing.
966 fn force_space_before(tok: &Token) -> bool {
967 debug!("tok: force_space_before {:?}", tok);
988 | Token::Dollar => true,
993 fn ident_like(tok: &Token) -> bool {
995 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
1000 fn next_space(tok: &Token) -> SpaceState {
1001 debug!("next_space: {:?}", tok);
1005 | Token::BinOp(BinOpToken::And)
1014 | Token::Question => SpaceState::Punctuation,
1019 | Token::OpenDelim(_)
1020 | Token::CloseDelim(_)
1021 | Token::Whitespace => SpaceState::Never,
1023 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
1025 _ => SpaceState::Always,
1029 /// Tries to convert a macro use into a short hand try expression. Returns None
1030 /// when the macro is not an instance of try! (or parsing the inner expression
1032 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
1033 if &format!("{}", mac.node.path) == "try" {
1034 let ts: TokenStream = mac.node.tts.clone().into();
1035 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1038 id: ast::NodeId::new(0), // dummy value
1039 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1040 span: mac.span, // incorrect span, but shouldn't matter too much
1041 attrs: ThinVec::new(),
1048 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1049 let snippet = context.snippet(mac.span);
1050 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1051 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1052 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1054 if paren_pos < bracket_pos && paren_pos < brace_pos {
1056 } else if bracket_pos < brace_pos {
1063 /// Indent each line according to the specified `indent`.
1091 fn indent_macro_snippet(
1092 context: &RewriteContext,
1095 ) -> Option<String> {
1096 let mut lines = LineClasses::new(macro_str);
1097 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1098 let mut trimmed_lines = Vec::with_capacity(16);
1100 let mut veto_trim = false;
1101 let min_prefix_space_width = lines
1102 .filter_map(|(kind, line)| {
1103 let mut trimmed = true;
1104 let prefix_space_width = if is_empty_line(&line) {
1107 Some(get_prefix_space_width(context, &line))
1109 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1110 veto_trim = kind.is_string() && !line.ends_with('\\');
1114 line.trim().to_owned()
1116 trimmed_lines.push((trimmed, line, prefix_space_width));
1122 first_line + "\n" + &trimmed_lines
1125 |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
1126 _ if !trimmed => line.to_owned(),
1127 Some(original_indent_width) => {
1128 let new_indent_width = indent.width() + original_indent_width
1129 .saturating_sub(min_prefix_space_width);
1130 let new_indent = Indent::from_width(context.config, new_indent_width);
1131 format!("{}{}", new_indent.to_string(context.config), line.trim())
1133 None => String::new(),
1136 .collect::<Vec<_>>()
1141 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1143 for c in s.chars() {
1146 '\t' => width += context.config.tab_spaces(),
1153 fn is_empty_line(s: &str) -> bool {
1154 s.is_empty() || s.chars().all(char::is_whitespace)
1157 // A very simple parser that just parses a macros 2.0 definition into its branches.
1158 // Currently we do not attempt to parse any further than that.
1160 struct MacroParser {
1165 // (`(` ... `)` `=>` `{` ... `}`)*
1166 fn parse(&mut self) -> Option<Macro> {
1167 let mut branches = vec![];
1168 while self.toks.look_ahead(1).is_some() {
1169 branches.push(self.parse_branch()?);
1172 Some(Macro { branches })
1175 // `(` ... `)` `=>` `{` ... `}`
1176 fn parse_branch(&mut self) -> Option<MacroBranch> {
1177 let tok = self.toks.next()?;
1178 let (lo, args_paren_kind) = match tok {
1179 TokenTree::Token(..) => return None,
1180 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
1182 let args = tok.joint().into();
1183 match self.toks.next()? {
1184 TokenTree::Token(_, Token::FatArrow) => {}
1187 let (mut hi, body, whole_body) = match self.toks.next()? {
1188 TokenTree::Token(..) => return None,
1189 TokenTree::Delimited(sp, _) => {
1190 let data = sp.data();
1193 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1198 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1203 span: mk_sp(lo, hi),
1212 // A parsed macros 2.0 macro definition.
1214 branches: Vec<MacroBranch>,
1217 // FIXME: it would be more efficient to use references to the token streams
1218 // rather than clone them, if we can make the borrowing work out.
1219 struct MacroBranch {
1221 args_paren_kind: DelimToken,
1222 args: ThinTokenStream,
1230 context: &RewriteContext,
1232 multi_branch_style: bool,
1233 ) -> Option<String> {
1234 // Only attempt to format function-like macros.
1235 if self.args_paren_kind != DelimToken::Paren {
1236 // FIXME(#1539): implement for non-sugared macros.
1241 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1243 if multi_branch_style {
1247 if !context.config.format_macro_bodies() {
1249 result += context.snippet(self.whole_body);
1250 return Some(result);
1253 // The macro body is the most interesting part. It might end up as various
1254 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1255 // parsed as regular Rust code (and note that these can be escaped using
1256 // `$$`). We'll try and format like an AST node, but we'll substitute
1257 // variables for new names with the same length first.
1259 let old_body = context.snippet(self.body).trim();
1260 let (body_str, substs) = replace_names(old_body)?;
1261 let has_block_body = old_body.starts_with('{');
1263 let mut config = context.config.clone();
1264 config.set().hide_parse_errors(true);
1268 let body_indent = if has_block_body {
1271 // We'll hack the indent below, take this into account when formatting,
1272 let body_indent = shape.indent.block_indent(&config);
1273 let new_width = config.max_width() - body_indent.width();
1274 config.set().max_width(new_width);
1278 // First try to format as items, then as statements.
1279 let new_body = match ::format_snippet(&body_str, &config) {
1280 Some(new_body) => new_body,
1281 None => match ::format_code_block(&body_str, &config) {
1282 Some(new_body) => new_body,
1283 None => return None,
1286 let new_body = wrap_str(new_body, config.max_width(), shape)?;
1288 // Indent the body since it is in a block.
1289 let indent_str = body_indent.to_string(&config);
1290 let mut new_body = LineClasses::new(new_body.trim_right())
1292 (String::new(), true),
1293 |(mut s, need_indent), (kind, ref l)| {
1294 if !l.is_empty() && need_indent {
1297 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1302 // Undo our replacement of macro variables.
1303 // FIXME: this could be *much* more efficient.
1304 for (old, new) in &substs {
1305 if old_body.find(new).is_some() {
1306 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1309 new_body = new_body.replace(new, old);
1313 result += new_body.trim();
1314 } else if !new_body.is_empty() {
1316 result += &new_body;
1317 result += &shape.indent.to_string(&config);
1326 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1328 /// # Expected syntax
1332 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1333 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1335 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1338 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1339 let mut result = String::with_capacity(1024);
1340 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1341 let nested_shape = shape
1342 .block_indent(context.config.tab_spaces())
1343 .with_max_width(context.config);
1345 result.push_str("lazy_static! {");
1346 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1348 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1349 match parser.$method($($arg,)*) {
1351 if parser.sess.span_diagnostic.has_errors() {
1352 parser.sess.span_diagnostic.reset_err_count();
1360 parser.sess.span_diagnostic.reset_err_count();
1366 while parser.token != Token::Eof {
1367 // Parse a `lazy_static!` item.
1368 let vis = ::utils::format_visibility(context, &parse_or!(parse_visibility, false));
1369 parser.eat_keyword(symbol::keywords::Static);
1370 parser.eat_keyword(symbol::keywords::Ref);
1371 let id = parse_or!(parse_ident);
1372 parser.eat(&Token::Colon);
1373 let ty = parse_or!(parse_ty);
1374 parser.eat(&Token::Eq);
1375 let expr = parse_or!(parse_expr);
1376 parser.eat(&Token::Semi);
1378 // Rewrite as a static item.
1379 let mut stmt = String::with_capacity(128);
1380 stmt.push_str(&format!(
1381 "{}static ref {}: {} =",
1384 ty.rewrite(context, nested_shape)?
1386 result.push_str(&::expr::rewrite_assign_rhs(
1390 nested_shape.sub_width(1)?,
1393 if parser.token != Token::Eof {
1394 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1398 result.push_str(&shape.indent.to_string_with_newline(context.config));