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, 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(path: &ast::Path, extra_ident: Option<ast::Ident>) -> String {
120 let name = if path.segments.len() == 1 {
121 // Avoid using pretty-printer in the common case.
122 format!("{}!", path.segments[0].ident)
127 Some(ident) if ident != symbol::keywords::Invalid.ident() => format!("{} {}", name, ident),
132 pub fn rewrite_macro(
134 extra_ident: Option<ast::Ident>,
135 context: &RewriteContext,
137 position: MacroPosition,
138 ) -> Option<String> {
139 context.inside_macro.replace(true);
140 let result = rewrite_macro_inner(mac, extra_ident, context, shape, position);
141 context.inside_macro.replace(false);
145 pub fn rewrite_macro_inner(
147 extra_ident: Option<ast::Ident>,
148 context: &RewriteContext,
150 position: MacroPosition,
151 ) -> Option<String> {
152 if context.config.use_try_shorthand() {
153 if let Some(expr) = convert_try_mac(mac, context) {
154 context.inside_macro.replace(false);
155 return expr.rewrite(context, shape);
159 let original_style = macro_style(mac, context);
161 let macro_name = rewrite_macro_name(&mac.node.path, extra_ident);
163 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
169 let ts: TokenStream = mac.node.stream();
170 let has_comment = contains_comment(context.snippet(mac.span));
171 if ts.is_empty() && !has_comment {
173 DelimToken::Paren if position == MacroPosition::Item => {
174 Some(format!("{}();", macro_name))
176 DelimToken::Paren => Some(format!("{}()", macro_name)),
177 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
178 DelimToken::Brace => Some(format!("{}{{}}", macro_name)),
182 // Format well-known macros which cannot be parsed as a valid AST.
183 // TODO: Maybe add more macros?
184 if macro_name == "lazy_static!" && !has_comment {
185 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
190 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
191 let mut arg_vec = Vec::new();
192 let mut vec_with_semi = false;
193 let mut trailing_comma = false;
195 if DelimToken::Brace != style {
197 match parse_macro_arg(&mut parser) {
198 Some(arg) => arg_vec.push(arg),
199 None => return Some(context.snippet(mac.span).to_owned()),
206 // Try to parse `vec![expr; expr]`
207 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
209 if parser.token != Token::Eof {
210 match parse_macro_arg(&mut parser) {
214 if parser.token == Token::Eof && arg_vec.len() == 2 {
215 vec_with_semi = true;
219 None => return Some(context.snippet(mac.span).to_owned()),
223 return Some(context.snippet(mac.span).to_owned());
225 _ => return Some(context.snippet(mac.span).to_owned()),
230 if parser.token == Token::Eof {
231 trailing_comma = true;
238 DelimToken::Paren => {
239 // Format macro invocation as function call, preserve the trailing
240 // comma because not all macros support them.
241 overflow::rewrite_with_parens(
244 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>(),
247 context.config.width_heuristics().fn_call_width,
249 Some(SeparatorTactic::Always)
251 Some(SeparatorTactic::Never)
253 ).map(|rw| match position {
254 MacroPosition::Item => format!("{};", rw),
258 DelimToken::Bracket => {
259 // Handle special case: `vec![expr; expr]`
261 let mac_shape = shape.offset_left(macro_name.len())?;
262 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
268 let total_overhead = lbr.len() + rbr.len() + 6;
269 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
270 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
271 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
272 if !lhs.contains('\n') && !rhs.contains('\n')
273 && lhs.len() + rhs.len() + total_overhead <= shape.width
275 Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
281 nested_shape.indent.to_string_with_newline(context.config),
283 nested_shape.indent.to_string_with_newline(context.config),
285 shape.indent.to_string_with_newline(context.config),
290 // If we are rewriting `vec!` macro or other special macros,
291 // then we can rewrite this as an usual array literal.
292 // Otherwise, we must preserve the original existence of trailing comma.
293 let macro_name = ¯o_name.as_str();
294 let mut force_trailing_comma = if trailing_comma {
295 Some(SeparatorTactic::Always)
297 Some(SeparatorTactic::Never)
299 if FORCED_BRACKET_MACROS.contains(macro_name) {
300 context.inside_macro.replace(false);
301 if context.use_block_indent() {
302 force_trailing_comma = Some(SeparatorTactic::Vertical);
305 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
306 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>();
307 let rewrite = rewrite_array(
313 force_trailing_comma,
314 Some(original_style),
316 let comma = match position {
317 MacroPosition::Item => ";",
321 Some(format!("{}{}", rewrite, comma))
324 DelimToken::Brace => {
325 // Skip macro invocations with braces, for now.
326 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
332 pub fn rewrite_macro_def(
333 context: &RewriteContext,
338 vis: &ast::Visibility,
340 ) -> Option<String> {
341 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
342 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
346 let mut parser = MacroParser::new(def.stream().into_trees());
347 let parsed_def = match parser.parse() {
349 None => return snippet,
352 let mut result = if def.legacy {
353 String::from("macro_rules!")
355 format!("{}macro", format_visibility(vis))
359 result += &ident.name.as_str();
361 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
363 let arm_shape = if multi_branch_style {
365 .block_indent(context.config.tab_spaces())
366 .with_max_width(context.config)
371 let branch_items = itemize_list(
372 context.snippet_provider,
373 parsed_def.branches.iter(),
376 |branch| branch.span.lo(),
377 |branch| branch.span.hi(),
378 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
379 context.snippet_provider.span_after(span, "{"),
382 ).collect::<Vec<_>>();
384 let fmt = ListFormatting {
385 tactic: DefinitiveListTactic::Vertical,
386 separator: if def.legacy { ";" } else { "" },
387 trailing_separator: SeparatorTactic::Always,
388 separator_place: SeparatorPlace::Back,
390 ends_with_newline: true,
391 preserve_newline: true,
392 config: context.config,
395 if multi_branch_style {
397 result += &arm_shape.indent.to_string_with_newline(context.config);
400 result += write_list(&branch_items, &fmt)?.as_str();
402 if multi_branch_style {
403 result += &indent.to_string_with_newline(context.config);
410 fn register_metavariable(
411 map: &mut HashMap<String, String>,
416 let mut new_name = String::new();
417 let mut old_name = String::new();
420 for _ in 0..(dollar_count - 1) {
425 new_name.push_str(&name);
426 old_name.push_str(&name);
428 result.push_str(&new_name);
429 map.insert(old_name, new_name);
432 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
433 // aren't causing problems.
434 // This should also work for escaped `$` variables, where we leave earlier `$`s.
435 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
436 // Each substitution will require five or six extra bytes.
437 let mut result = String::with_capacity(input.len() + 64);
438 let mut substs = HashMap::new();
439 let mut dollar_count = 0;
440 let mut cur_name = String::new();
442 for (kind, c) in CharClasses::new(input.chars()) {
443 if kind != FullCodeCharKind::Normal {
447 } else if dollar_count == 0 {
449 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
450 // Terminates a name following one or more dollars.
451 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
456 } else if c == '(' && cur_name.is_empty() {
457 // FIXME: Support macro def with repeat.
459 } else if c.is_alphanumeric() || c == '_' {
464 if !cur_name.is_empty() {
465 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
468 debug!("replace_names `{}` {:?}", result, substs);
470 Some((result, substs))
473 #[derive(Debug, Clone)]
476 MetaVariable(ast::Ident, String),
477 /// e.g. `$($foo: expr),*`
479 /// `()`, `[]` or `{}`.
481 /// Inner arguments inside delimiters.
483 /// Something after the closing delimiter and the repeat token, if available.
484 Option<Box<ParsedMacroArg>>,
485 /// The repeat token. This could be one of `*`, `+` or `?`.
488 /// e.g. `[derive(Debug)]`
489 Delimited(DelimToken, Vec<ParsedMacroArg>),
490 /// A possible separator. e.g. `,` or `;`.
491 Separator(String, String),
492 /// Other random stuff that does not fit to other kinds.
493 /// e.g. `== foo` in `($x: expr == foo)`.
494 Other(String, String),
497 fn delim_token_to_str(
498 context: &RewriteContext,
499 delim_token: &DelimToken,
501 use_multiple_lines: bool,
502 ) -> (String, String) {
503 let (lhs, rhs) = match *delim_token {
504 DelimToken::Paren => ("(", ")"),
505 DelimToken::Bracket => ("[", "]"),
506 DelimToken::Brace => ("{ ", " }"),
507 DelimToken::NoDelim => ("", ""),
509 if use_multiple_lines {
510 let indent_str = shape.indent.to_string_with_newline(context.config);
511 let nested_indent_str = shape
513 .block_indent(context.config)
514 .to_string_with_newline(context.config);
516 format!("{}{}", lhs, nested_indent_str),
517 format!("{}{}", indent_str, rhs),
520 (lhs.to_owned(), rhs.to_owned())
525 fn starts_with_brace(&self) -> bool {
527 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
528 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
533 fn starts_with_dollar(&self) -> bool {
535 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
540 fn ends_with_space(&self) -> bool {
542 MacroArgKind::Separator(..) => true,
547 fn has_meta_var(&self) -> bool {
549 MacroArgKind::MetaVariable(..) => true,
550 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
557 context: &RewriteContext,
559 use_multiple_lines: bool,
560 ) -> Option<String> {
561 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
562 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false);
563 let inner = wrap_macro_args(context, args, shape)?;
564 if lhs.len() + inner.len() + rhs.len() <= shape.width {
565 return Some((lhs, inner, rhs));
568 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true);
569 let nested_shape = shape
570 .block_indent(context.config.tab_spaces())
571 .with_max_width(context.config);
572 let inner = wrap_macro_args(context, args, nested_shape)?;
573 Some((lhs, inner, rhs))
577 MacroArgKind::MetaVariable(ty, ref name) => {
578 Some(format!("${}:{}", name, ty.name.as_str()))
580 MacroArgKind::Repeat(ref delim_tok, ref args, ref another, ref tok) => {
581 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
582 let another = another
584 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
585 .unwrap_or_else(|| "".to_owned());
586 let repeat_tok = pprust::token_to_string(tok);
588 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
590 MacroArgKind::Delimited(ref delim_tok, ref args) => {
591 rewrite_delimited_inner(delim_tok, args)
592 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
594 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
595 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
600 #[derive(Debug, Clone)]
601 struct ParsedMacroArg {
606 impl ParsedMacroArg {
609 context: &RewriteContext,
611 use_multiple_lines: bool,
612 ) -> Option<String> {
613 self.kind.rewrite(context, shape, use_multiple_lines)
617 /// Parses macro arguments on macro def.
618 struct MacroArgParser {
619 /// Holds either a name of the next metavariable, a separator or a junk.
621 /// The start position on the current buffer.
623 /// The first token of the current buffer.
625 /// Set to true if we are parsing a metavariable or a repeat.
627 /// The position of the last token.
629 /// The last token parsed.
631 /// Holds the parsed arguments.
632 result: Vec<ParsedMacroArg>,
635 fn last_tok(tt: &TokenTree) -> Token {
637 TokenTree::Token(_, ref t) => t.clone(),
638 TokenTree::Delimited(_, ref d) => d.close_token(),
642 impl MacroArgParser {
643 pub fn new() -> MacroArgParser {
649 last_tok: Token::Eof,
650 start_tok: Token::Eof,
655 fn set_last_tok(&mut self, tok: &TokenTree) {
656 self.hi = tok.span().hi();
657 self.last_tok = last_tok(tok);
660 fn add_separator(&mut self) {
661 let prefix = if self.need_space_prefix() {
666 self.result.push(ParsedMacroArg {
667 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
668 span: mk_sp(self.lo, self.hi),
673 fn add_other(&mut self) {
674 let prefix = if self.need_space_prefix() {
679 self.result.push(ParsedMacroArg {
680 kind: MacroArgKind::Other(self.buf.clone(), prefix),
681 span: mk_sp(self.lo, self.hi),
686 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
688 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
689 self.result.push(ParsedMacroArg {
690 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
691 span: mk_sp(self.lo, sp.hi()),
695 self.is_meta_var = false;
702 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
703 self.result.push(ParsedMacroArg {
704 kind: MacroArgKind::Delimited(delim, inner),
712 inner: Vec<ParsedMacroArg>,
717 let mut buffer = String::new();
718 let mut first = false;
719 let mut lo = span.lo();
720 let mut hi = span.hi();
722 // Parse '*', '+' or '?.
723 for ref tok in iter {
724 self.set_last_tok(tok);
727 lo = tok.span().lo();
731 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
732 | TokenTree::Token(_, Token::Question)
733 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
736 TokenTree::Token(sp, ref t) => {
737 buffer.push_str(&pprust::token_to_string(t));
744 // There could be some random stuff between ')' and '*', '+' or '?'.
745 let another = if buffer.trim().is_empty() {
748 Some(Box::new(ParsedMacroArg {
749 kind: MacroArgKind::Other(buffer, "".to_owned()),
754 self.result.push(ParsedMacroArg {
755 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
756 span: mk_sp(self.lo, self.hi),
761 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
762 if self.buf.is_empty() {
764 self.start_tok = t.clone();
766 let needs_space = match next_space(&self.last_tok) {
767 SpaceState::Ident => ident_like(t),
768 SpaceState::Punctuation => !ident_like(t),
769 SpaceState::Always => true,
770 SpaceState::Never => false,
772 if force_space_before(t) || needs_space {
777 self.buf.push_str(&pprust::token_to_string(t));
780 fn need_space_prefix(&self) -> bool {
781 if self.result.is_empty() {
785 let last_arg = self.result.last().unwrap();
786 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
787 if ident_like(&self.start_tok) {
790 if self.start_tok == Token::Colon {
795 if force_space_before(&self.start_tok) {
802 /// Returns a collection of parsed macro def's arguments.
803 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
804 let mut iter = (tokens.into(): TokenStream).trees();
806 while let Some(ref tok) = iter.next() {
808 TokenTree::Token(sp, Token::Dollar) => {
809 // We always want to add a separator before meta variables.
810 if !self.buf.is_empty() {
811 self.add_separator();
814 // Start keeping the name of this metavariable in the buffer.
815 self.is_meta_var = true;
817 self.start_tok = Token::Dollar;
819 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
820 self.add_meta_variable(&mut iter)?;
822 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
823 TokenTree::Delimited(sp, delimited) => {
824 if !self.buf.is_empty() {
825 if next_space(&self.last_tok) == SpaceState::Always {
826 self.add_separator();
832 // Parse the stuff inside delimiters.
833 let mut parser = MacroArgParser::new();
835 let delimited_arg = parser.parse(delimited.tts.clone())?;
837 if self.is_meta_var {
838 self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp)?;
840 self.add_delimited(delimited_arg, delimited.delim, *sp);
845 self.set_last_tok(tok);
848 // We are left with some stuff in the buffer. Since there is nothing
849 // left to separate, add this as `Other`.
850 if !self.buf.is_empty() {
859 context: &RewriteContext,
860 args: &[ParsedMacroArg],
862 ) -> Option<String> {
863 wrap_macro_args_inner(context, args, shape, false)
864 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
867 fn wrap_macro_args_inner(
868 context: &RewriteContext,
869 args: &[ParsedMacroArg],
871 use_multiple_lines: bool,
872 ) -> Option<String> {
873 let mut result = String::with_capacity(128);
874 let mut iter = args.iter().peekable();
875 let indent_str = shape.indent.to_string_with_newline(context.config);
877 while let Some(ref arg) = iter.next() {
878 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
880 if use_multiple_lines
881 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
883 if arg.kind.ends_with_space() {
886 result.push_str(&indent_str);
887 } else if let Some(ref next_arg) = iter.peek() {
888 let space_before_dollar =
889 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
890 let space_before_brace = next_arg.kind.starts_with_brace();
891 if space_before_dollar || space_before_brace {
897 if !use_multiple_lines && result.len() >= shape.width {
904 // This is a bit sketchy. The token rules probably need tweaking, but it works
905 // for some common cases. I hope the basic logic is sufficient. Note that the
906 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
907 // and `(`/`)` have special meaning.
909 // We always try and format on one line.
910 // FIXME: Use multi-line when every thing does not fit on one line.
911 fn format_macro_args(
912 context: &RewriteContext,
913 toks: ThinTokenStream,
915 ) -> Option<String> {
916 let parsed_args = MacroArgParser::new().parse(toks)?;
917 wrap_macro_args(context, &parsed_args, shape)
920 // We should insert a space if the next token is a:
921 #[derive(Copy, Clone, PartialEq)]
925 Ident, // Or ident/literal-like thing.
929 fn force_space_before(tok: &Token) -> bool {
930 debug!("tok: force_space_before {:?}", tok);
951 | Token::Dollar => true,
956 fn ident_like(tok: &Token) -> bool {
958 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
963 fn next_space(tok: &Token) -> SpaceState {
964 debug!("next_space: {:?}", tok);
968 | Token::BinOp(BinOpToken::And)
977 | Token::Question => SpaceState::Punctuation,
982 | Token::OpenDelim(_)
983 | Token::CloseDelim(_)
984 | Token::Whitespace => SpaceState::Never,
986 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
988 _ => SpaceState::Always,
992 /// Tries to convert a macro use into a short hand try expression. Returns None
993 /// when the macro is not an instance of try! (or parsing the inner expression
995 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
996 if &format!("{}", mac.node.path) == "try" {
997 let ts: TokenStream = mac.node.tts.clone().into();
998 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1001 id: ast::NodeId::new(0), // dummy value
1002 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1003 span: mac.span, // incorrect span, but shouldn't matter too much
1004 attrs: ThinVec::new(),
1011 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1012 let snippet = context.snippet(mac.span);
1013 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1014 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1015 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1017 if paren_pos < bracket_pos && paren_pos < brace_pos {
1019 } else if bracket_pos < brace_pos {
1026 /// Indent each line according to the specified `indent`.
1054 fn indent_macro_snippet(
1055 context: &RewriteContext,
1058 ) -> Option<String> {
1059 let mut lines = LineClasses::new(macro_str);
1060 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1061 let mut trimmed_lines = Vec::with_capacity(16);
1063 let mut veto_trim = false;
1064 let min_prefix_space_width = lines
1065 .filter_map(|(kind, line)| {
1066 let mut trimmed = true;
1067 let prefix_space_width = if is_empty_line(&line) {
1070 Some(get_prefix_space_width(context, &line))
1072 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1073 veto_trim = kind.is_string() && !line.ends_with('\\');
1077 line.trim().to_owned()
1079 trimmed_lines.push((trimmed, line, prefix_space_width));
1089 |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
1090 _ if !trimmed => line.to_owned(),
1091 Some(original_indent_width) => {
1092 let new_indent_width = indent.width()
1093 + original_indent_width
1094 .checked_sub(min_prefix_space_width)
1096 let new_indent = Indent::from_width(context.config, new_indent_width);
1097 format!("{}{}", new_indent.to_string(context.config), line.trim())
1099 None => String::new(),
1102 .collect::<Vec<_>>()
1107 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1109 for c in s.chars() {
1112 '\t' => width += context.config.tab_spaces(),
1119 fn is_empty_line(s: &str) -> bool {
1120 s.is_empty() || s.chars().all(char::is_whitespace)
1123 // A very simple parser that just parses a macros 2.0 definition into its branches.
1124 // Currently we do not attempt to parse any further than that.
1126 struct MacroParser {
1131 // (`(` ... `)` `=>` `{` ... `}`)*
1132 fn parse(&mut self) -> Option<Macro> {
1133 let mut branches = vec![];
1134 while self.toks.look_ahead(1).is_some() {
1135 branches.push(self.parse_branch()?);
1138 Some(Macro { branches })
1141 // `(` ... `)` `=>` `{` ... `}`
1142 fn parse_branch(&mut self) -> Option<MacroBranch> {
1143 let tok = self.toks.next()?;
1144 let (lo, args_paren_kind) = match tok {
1145 TokenTree::Token(..) => return None,
1146 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
1148 let args = tok.joint().into();
1149 match self.toks.next()? {
1150 TokenTree::Token(_, Token::FatArrow) => {}
1153 let (mut hi, body) = match self.toks.next()? {
1154 TokenTree::Token(..) => return None,
1155 TokenTree::Delimited(sp, _) => {
1156 let data = sp.data();
1159 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1163 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1168 span: mk_sp(lo, hi),
1176 // A parsed macros 2.0 macro definition.
1178 branches: Vec<MacroBranch>,
1181 // FIXME: it would be more efficient to use references to the token streams
1182 // rather than clone them, if we can make the borrowing work out.
1183 struct MacroBranch {
1185 args_paren_kind: DelimToken,
1186 args: ThinTokenStream,
1193 context: &RewriteContext,
1195 multi_branch_style: bool,
1196 ) -> Option<String> {
1197 // Only attempt to format function-like macros.
1198 if self.args_paren_kind != DelimToken::Paren {
1199 // FIXME(#1539): implement for non-sugared macros.
1204 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1206 if multi_branch_style {
1210 // The macro body is the most interesting part. It might end up as various
1211 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1212 // parsed as regular Rust code (and note that these can be escaped using
1213 // `$$`). We'll try and format like an AST node, but we'll substitute
1214 // variables for new names with the same length first.
1216 let old_body = context.snippet(self.body).trim();
1217 let (body_str, substs) = replace_names(old_body)?;
1219 let mut config = context.config.clone();
1220 config.set().hide_parse_errors(true);
1224 let has_block_body = old_body.starts_with('{');
1226 let body_indent = if has_block_body {
1229 // We'll hack the indent below, take this into account when formatting,
1230 let body_indent = shape.indent.block_indent(&config);
1231 let new_width = config.max_width() - body_indent.width();
1232 config.set().max_width(new_width);
1236 // First try to format as items, then as statements.
1237 let new_body = match ::format_snippet(&body_str, &config) {
1238 Some(new_body) => new_body,
1239 None => match ::format_code_block(&body_str, &config) {
1240 Some(new_body) => new_body,
1241 None => return None,
1244 let new_body = wrap_str(new_body, config.max_width(), shape)?;
1246 // Indent the body since it is in a block.
1247 let indent_str = body_indent.to_string(&config);
1248 let mut new_body = LineClasses::new(new_body.trim_right())
1250 (String::new(), true),
1251 |(mut s, need_indent), (kind, ref l)| {
1252 if !l.is_empty() && need_indent {
1255 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1260 // Undo our replacement of macro variables.
1261 // FIXME: this could be *much* more efficient.
1262 for (old, new) in &substs {
1263 if old_body.find(new).is_some() {
1264 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1267 new_body = new_body.replace(new, old);
1271 result += new_body.trim();
1272 } else if !new_body.is_empty() {
1274 result += &new_body;
1275 result += &shape.indent.to_string(&config);
1284 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1286 /// # Expected syntax
1290 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1291 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1293 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1296 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1297 let mut result = String::with_capacity(1024);
1298 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1299 let nested_shape = shape.block_indent(context.config.tab_spaces());
1301 result.push_str("lazy_static! {");
1302 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1304 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1305 match parser.$method($($arg,)*) {
1307 if parser.sess.span_diagnostic.has_errors() {
1308 parser.sess.span_diagnostic.reset_err_count();
1316 parser.sess.span_diagnostic.reset_err_count();
1322 while parser.token != Token::Eof {
1323 // Parse a `lazy_static!` item.
1324 let vis = ::utils::format_visibility(&parse_or!(parse_visibility, false));
1325 parser.eat_keyword(symbol::keywords::Static);
1326 parser.eat_keyword(symbol::keywords::Ref);
1327 let id = parse_or!(parse_ident);
1328 parser.eat(&Token::Colon);
1329 let ty = parse_or!(parse_ty);
1330 parser.eat(&Token::Eq);
1331 let expr = parse_or!(parse_expr);
1332 parser.eat(&Token::Semi);
1334 // Rewrite as a static item.
1335 let mut stmt = String::with_capacity(128);
1336 stmt.push_str(&format!(
1337 "{}static ref {}: {} =",
1340 ty.rewrite(context, nested_shape)?
1342 result.push_str(&::expr::rewrite_assign_rhs(
1346 nested_shape.sub_width(1)?,
1349 if parser.token != Token::Eof {
1350 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1354 result.push_str(&shape.indent.to_string_with_newline(context.config));