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 // 8 = `vec![]` + `; `
263 let total_overhead = 8;
264 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
265 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
266 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
267 if !lhs.contains('\n')
268 && !rhs.contains('\n')
269 && lhs.len() + rhs.len() + total_overhead <= shape.width
271 Some(format!("{}[{}; {}]", macro_name, lhs, rhs))
276 nested_shape.indent.to_string_with_newline(context.config),
278 nested_shape.indent.to_string_with_newline(context.config),
280 shape.indent.to_string_with_newline(context.config),
284 // If we are rewriting `vec!` macro or other special macros,
285 // then we can rewrite this as an usual array literal.
286 // Otherwise, we must preserve the original existence of trailing comma.
287 let macro_name = ¯o_name.as_str();
288 let mut force_trailing_comma = if trailing_comma {
289 Some(SeparatorTactic::Always)
291 Some(SeparatorTactic::Never)
293 if FORCED_BRACKET_MACROS.contains(macro_name) {
294 context.inside_macro.replace(false);
295 if context.use_block_indent() {
296 force_trailing_comma = Some(SeparatorTactic::Vertical);
299 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
300 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>();
301 let rewrite = rewrite_array(
307 force_trailing_comma,
308 Some(original_style),
310 let comma = match position {
311 MacroPosition::Item => ";",
315 Some(format!("{}{}", rewrite, comma))
318 DelimToken::Brace => {
319 // Skip macro invocations with braces, for now.
320 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
326 pub fn rewrite_macro_def(
327 context: &RewriteContext,
332 vis: &ast::Visibility,
334 ) -> Option<String> {
335 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
336 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
340 let mut parser = MacroParser::new(def.stream().into_trees());
341 let parsed_def = match parser.parse() {
343 None => return snippet,
346 let mut result = if def.legacy {
347 String::from("macro_rules!")
349 format!("{}macro", format_visibility(vis))
353 result += &ident.name.as_str();
355 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
357 let arm_shape = if multi_branch_style {
359 .block_indent(context.config.tab_spaces())
360 .with_max_width(context.config)
365 let branch_items = itemize_list(
366 context.snippet_provider,
367 parsed_def.branches.iter(),
370 |branch| branch.span.lo(),
371 |branch| branch.span.hi(),
372 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
373 context.snippet_provider.span_after(span, "{"),
376 ).collect::<Vec<_>>();
378 let fmt = ListFormatting {
379 tactic: DefinitiveListTactic::Vertical,
380 separator: if def.legacy { ";" } else { "" },
381 trailing_separator: SeparatorTactic::Always,
382 separator_place: SeparatorPlace::Back,
384 ends_with_newline: true,
385 preserve_newline: true,
386 config: context.config,
389 if multi_branch_style {
391 result += &arm_shape.indent.to_string_with_newline(context.config);
394 result += write_list(&branch_items, &fmt)?.as_str();
396 if multi_branch_style {
397 result += &indent.to_string_with_newline(context.config);
404 fn register_metavariable(
405 map: &mut HashMap<String, String>,
410 let mut new_name = String::new();
411 let mut old_name = String::new();
414 for _ in 0..(dollar_count - 1) {
419 new_name.push_str(&name);
420 old_name.push_str(&name);
422 result.push_str(&new_name);
423 map.insert(old_name, new_name);
426 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
427 // aren't causing problems.
428 // This should also work for escaped `$` variables, where we leave earlier `$`s.
429 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
430 // Each substitution will require five or six extra bytes.
431 let mut result = String::with_capacity(input.len() + 64);
432 let mut substs = HashMap::new();
433 let mut dollar_count = 0;
434 let mut cur_name = String::new();
436 for (kind, c) in CharClasses::new(input.chars()) {
437 if kind != FullCodeCharKind::Normal {
441 } else if dollar_count == 0 {
443 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
444 // Terminates a name following one or more dollars.
445 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
450 } else if c == '(' && cur_name.is_empty() {
451 // FIXME: Support macro def with repeat.
453 } else if c.is_alphanumeric() || c == '_' {
458 if !cur_name.is_empty() {
459 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
462 debug!("replace_names `{}` {:?}", result, substs);
464 Some((result, substs))
467 #[derive(Debug, Clone)]
470 MetaVariable(ast::Ident, String),
471 /// e.g. `$($foo: expr),*`
473 /// `()`, `[]` or `{}`.
475 /// Inner arguments inside delimiters.
477 /// Something after the closing delimiter and the repeat token, if available.
478 Option<Box<ParsedMacroArg>>,
479 /// The repeat token. This could be one of `*`, `+` or `?`.
482 /// e.g. `[derive(Debug)]`
483 Delimited(DelimToken, Vec<ParsedMacroArg>),
484 /// A possible separator. e.g. `,` or `;`.
485 Separator(String, String),
486 /// Other random stuff that does not fit to other kinds.
487 /// e.g. `== foo` in `($x: expr == foo)`.
488 Other(String, String),
491 fn delim_token_to_str(
492 context: &RewriteContext,
493 delim_token: &DelimToken,
495 use_multiple_lines: bool,
496 ) -> (String, String) {
497 let (lhs, rhs) = match *delim_token {
498 DelimToken::Paren => ("(", ")"),
499 DelimToken::Bracket => ("[", "]"),
500 DelimToken::Brace => ("{ ", " }"),
501 DelimToken::NoDelim => ("", ""),
503 if use_multiple_lines {
504 let indent_str = shape.indent.to_string_with_newline(context.config);
505 let nested_indent_str = shape
507 .block_indent(context.config)
508 .to_string_with_newline(context.config);
510 format!("{}{}", lhs, nested_indent_str),
511 format!("{}{}", indent_str, rhs),
514 (lhs.to_owned(), rhs.to_owned())
519 fn starts_with_brace(&self) -> bool {
521 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
522 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
527 fn starts_with_dollar(&self) -> bool {
529 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
534 fn ends_with_space(&self) -> bool {
536 MacroArgKind::Separator(..) => true,
541 fn has_meta_var(&self) -> bool {
543 MacroArgKind::MetaVariable(..) => true,
544 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
551 context: &RewriteContext,
553 use_multiple_lines: bool,
554 ) -> Option<String> {
555 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
556 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false);
557 let inner = wrap_macro_args(context, args, shape)?;
558 if lhs.len() + inner.len() + rhs.len() <= shape.width {
559 return Some((lhs, inner, rhs));
562 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true);
563 let nested_shape = shape
564 .block_indent(context.config.tab_spaces())
565 .with_max_width(context.config);
566 let inner = wrap_macro_args(context, args, nested_shape)?;
567 Some((lhs, inner, rhs))
571 MacroArgKind::MetaVariable(ty, ref name) => {
572 Some(format!("${}:{}", name, ty.name.as_str()))
574 MacroArgKind::Repeat(ref delim_tok, ref args, ref another, ref tok) => {
575 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
576 let another = another
578 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
579 .unwrap_or_else(|| "".to_owned());
580 let repeat_tok = pprust::token_to_string(tok);
582 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
584 MacroArgKind::Delimited(ref delim_tok, ref args) => {
585 rewrite_delimited_inner(delim_tok, args)
586 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
588 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
589 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
594 #[derive(Debug, Clone)]
595 struct ParsedMacroArg {
600 impl ParsedMacroArg {
603 context: &RewriteContext,
605 use_multiple_lines: bool,
606 ) -> Option<String> {
607 self.kind.rewrite(context, shape, use_multiple_lines)
611 /// Parses macro arguments on macro def.
612 struct MacroArgParser {
613 /// Holds either a name of the next metavariable, a separator or a junk.
615 /// The start position on the current buffer.
617 /// The first token of the current buffer.
619 /// Set to true if we are parsing a metavariable or a repeat.
621 /// The position of the last token.
623 /// The last token parsed.
625 /// Holds the parsed arguments.
626 result: Vec<ParsedMacroArg>,
629 fn last_tok(tt: &TokenTree) -> Token {
631 TokenTree::Token(_, ref t) => t.clone(),
632 TokenTree::Delimited(_, ref d) => d.close_token(),
636 impl MacroArgParser {
637 pub fn new() -> MacroArgParser {
643 last_tok: Token::Eof,
644 start_tok: Token::Eof,
649 fn set_last_tok(&mut self, tok: &TokenTree) {
650 self.hi = tok.span().hi();
651 self.last_tok = last_tok(tok);
654 fn add_separator(&mut self) {
655 let prefix = if self.need_space_prefix() {
660 self.result.push(ParsedMacroArg {
661 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
662 span: mk_sp(self.lo, self.hi),
667 fn add_other(&mut self) {
668 let prefix = if self.need_space_prefix() {
673 self.result.push(ParsedMacroArg {
674 kind: MacroArgKind::Other(self.buf.clone(), prefix),
675 span: mk_sp(self.lo, self.hi),
680 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
682 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
683 self.result.push(ParsedMacroArg {
684 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
685 span: mk_sp(self.lo, sp.hi()),
689 self.is_meta_var = false;
696 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
697 self.result.push(ParsedMacroArg {
698 kind: MacroArgKind::Delimited(delim, inner),
706 inner: Vec<ParsedMacroArg>,
711 let mut buffer = String::new();
712 let mut first = false;
713 let mut lo = span.lo();
714 let mut hi = span.hi();
716 // Parse '*', '+' or '?.
717 for ref tok in iter {
718 self.set_last_tok(tok);
721 lo = tok.span().lo();
725 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
726 | TokenTree::Token(_, Token::Question)
727 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
730 TokenTree::Token(sp, ref t) => {
731 buffer.push_str(&pprust::token_to_string(t));
738 // There could be some random stuff between ')' and '*', '+' or '?'.
739 let another = if buffer.trim().is_empty() {
742 Some(Box::new(ParsedMacroArg {
743 kind: MacroArgKind::Other(buffer, "".to_owned()),
748 self.result.push(ParsedMacroArg {
749 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
750 span: mk_sp(self.lo, self.hi),
755 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
756 if self.buf.is_empty() {
758 self.start_tok = t.clone();
760 let needs_space = match next_space(&self.last_tok) {
761 SpaceState::Ident => ident_like(t),
762 SpaceState::Punctuation => !ident_like(t),
763 SpaceState::Always => true,
764 SpaceState::Never => false,
766 if force_space_before(t) || needs_space {
771 self.buf.push_str(&pprust::token_to_string(t));
774 fn need_space_prefix(&self) -> bool {
775 if self.result.is_empty() {
779 let last_arg = self.result.last().unwrap();
780 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
781 if ident_like(&self.start_tok) {
784 if self.start_tok == Token::Colon {
789 if force_space_before(&self.start_tok) {
796 /// Returns a collection of parsed macro def's arguments.
797 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
798 let mut iter = (tokens.into(): TokenStream).trees();
800 while let Some(ref tok) = iter.next() {
802 TokenTree::Token(sp, Token::Dollar) => {
803 // We always want to add a separator before meta variables.
804 if !self.buf.is_empty() {
805 self.add_separator();
808 // Start keeping the name of this metavariable in the buffer.
809 self.is_meta_var = true;
811 self.start_tok = Token::Dollar;
813 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
814 self.add_meta_variable(&mut iter)?;
816 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
817 TokenTree::Delimited(sp, delimited) => {
818 if !self.buf.is_empty() {
819 if next_space(&self.last_tok) == SpaceState::Always {
820 self.add_separator();
826 // Parse the stuff inside delimiters.
827 let mut parser = MacroArgParser::new();
829 let delimited_arg = parser.parse(delimited.tts.clone())?;
831 if self.is_meta_var {
832 self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp)?;
834 self.add_delimited(delimited_arg, delimited.delim, *sp);
839 self.set_last_tok(tok);
842 // We are left with some stuff in the buffer. Since there is nothing
843 // left to separate, add this as `Other`.
844 if !self.buf.is_empty() {
853 context: &RewriteContext,
854 args: &[ParsedMacroArg],
856 ) -> Option<String> {
857 wrap_macro_args_inner(context, args, shape, false)
858 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
861 fn wrap_macro_args_inner(
862 context: &RewriteContext,
863 args: &[ParsedMacroArg],
865 use_multiple_lines: bool,
866 ) -> Option<String> {
867 let mut result = String::with_capacity(128);
868 let mut iter = args.iter().peekable();
869 let indent_str = shape.indent.to_string_with_newline(context.config);
871 while let Some(ref arg) = iter.next() {
872 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
874 if use_multiple_lines
875 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
877 if arg.kind.ends_with_space() {
880 result.push_str(&indent_str);
881 } else if let Some(ref next_arg) = iter.peek() {
882 let space_before_dollar =
883 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
884 let space_before_brace = next_arg.kind.starts_with_brace();
885 if space_before_dollar || space_before_brace {
891 if !use_multiple_lines && result.len() >= shape.width {
898 // This is a bit sketchy. The token rules probably need tweaking, but it works
899 // for some common cases. I hope the basic logic is sufficient. Note that the
900 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
901 // and `(`/`)` have special meaning.
903 // We always try and format on one line.
904 // FIXME: Use multi-line when every thing does not fit on one line.
905 fn format_macro_args(
906 context: &RewriteContext,
907 toks: ThinTokenStream,
909 ) -> Option<String> {
910 let parsed_args = MacroArgParser::new().parse(toks)?;
911 wrap_macro_args(context, &parsed_args, shape)
914 // We should insert a space if the next token is a:
915 #[derive(Copy, Clone, PartialEq)]
919 Ident, // Or ident/literal-like thing.
923 fn force_space_before(tok: &Token) -> bool {
924 debug!("tok: force_space_before {:?}", tok);
945 | Token::Dollar => true,
950 fn ident_like(tok: &Token) -> bool {
952 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
957 fn next_space(tok: &Token) -> SpaceState {
958 debug!("next_space: {:?}", tok);
962 | Token::BinOp(BinOpToken::And)
971 | Token::Question => SpaceState::Punctuation,
976 | Token::OpenDelim(_)
977 | Token::CloseDelim(_)
978 | Token::Whitespace => SpaceState::Never,
980 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
982 _ => SpaceState::Always,
986 /// Tries to convert a macro use into a short hand try expression. Returns None
987 /// when the macro is not an instance of try! (or parsing the inner expression
989 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
990 if &format!("{}", mac.node.path) == "try" {
991 let ts: TokenStream = mac.node.tts.clone().into();
992 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
995 id: ast::NodeId::new(0), // dummy value
996 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
997 span: mac.span, // incorrect span, but shouldn't matter too much
998 attrs: ThinVec::new(),
1005 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1006 let snippet = context.snippet(mac.span);
1007 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1008 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1009 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1011 if paren_pos < bracket_pos && paren_pos < brace_pos {
1013 } else if bracket_pos < brace_pos {
1020 /// Indent each line according to the specified `indent`.
1048 fn indent_macro_snippet(
1049 context: &RewriteContext,
1052 ) -> Option<String> {
1053 let mut lines = LineClasses::new(macro_str);
1054 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1055 let mut trimmed_lines = Vec::with_capacity(16);
1057 let mut veto_trim = false;
1058 let min_prefix_space_width = lines
1059 .filter_map(|(kind, line)| {
1060 let mut trimmed = true;
1061 let prefix_space_width = if is_empty_line(&line) {
1064 Some(get_prefix_space_width(context, &line))
1066 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1067 veto_trim = kind.is_string() && !line.ends_with('\\');
1071 line.trim().to_owned()
1073 trimmed_lines.push((trimmed, line, prefix_space_width));
1083 |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
1084 _ if !trimmed => line.to_owned(),
1085 Some(original_indent_width) => {
1086 let new_indent_width = indent.width()
1087 + original_indent_width.saturating_sub(min_prefix_space_width);
1088 let new_indent = Indent::from_width(context.config, new_indent_width);
1089 format!("{}{}", new_indent.to_string(context.config), line.trim())
1091 None => String::new(),
1094 .collect::<Vec<_>>()
1099 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1101 for c in s.chars() {
1104 '\t' => width += context.config.tab_spaces(),
1111 fn is_empty_line(s: &str) -> bool {
1112 s.is_empty() || s.chars().all(char::is_whitespace)
1115 // A very simple parser that just parses a macros 2.0 definition into its branches.
1116 // Currently we do not attempt to parse any further than that.
1118 struct MacroParser {
1123 // (`(` ... `)` `=>` `{` ... `}`)*
1124 fn parse(&mut self) -> Option<Macro> {
1125 let mut branches = vec![];
1126 while self.toks.look_ahead(1).is_some() {
1127 branches.push(self.parse_branch()?);
1130 Some(Macro { branches })
1133 // `(` ... `)` `=>` `{` ... `}`
1134 fn parse_branch(&mut self) -> Option<MacroBranch> {
1135 let tok = self.toks.next()?;
1136 let (lo, args_paren_kind) = match tok {
1137 TokenTree::Token(..) => return None,
1138 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
1140 let args = tok.joint().into();
1141 match self.toks.next()? {
1142 TokenTree::Token(_, Token::FatArrow) => {}
1145 let (mut hi, body) = match self.toks.next()? {
1146 TokenTree::Token(..) => return None,
1147 TokenTree::Delimited(sp, _) => {
1148 let data = sp.data();
1151 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1155 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1160 span: mk_sp(lo, hi),
1168 // A parsed macros 2.0 macro definition.
1170 branches: Vec<MacroBranch>,
1173 // FIXME: it would be more efficient to use references to the token streams
1174 // rather than clone them, if we can make the borrowing work out.
1175 struct MacroBranch {
1177 args_paren_kind: DelimToken,
1178 args: ThinTokenStream,
1185 context: &RewriteContext,
1187 multi_branch_style: bool,
1188 ) -> Option<String> {
1189 // Only attempt to format function-like macros.
1190 if self.args_paren_kind != DelimToken::Paren {
1191 // FIXME(#1539): implement for non-sugared macros.
1196 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1198 if multi_branch_style {
1202 // The macro body is the most interesting part. It might end up as various
1203 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1204 // parsed as regular Rust code (and note that these can be escaped using
1205 // `$$`). We'll try and format like an AST node, but we'll substitute
1206 // variables for new names with the same length first.
1208 let old_body = context.snippet(self.body).trim();
1209 let (body_str, substs) = replace_names(old_body)?;
1211 let mut config = context.config.clone();
1212 config.set().hide_parse_errors(true);
1216 let has_block_body = old_body.starts_with('{');
1218 let body_indent = if has_block_body {
1221 // We'll hack the indent below, take this into account when formatting,
1222 let body_indent = shape.indent.block_indent(&config);
1223 let new_width = config.max_width() - body_indent.width();
1224 config.set().max_width(new_width);
1228 // First try to format as items, then as statements.
1229 let new_body = match ::format_snippet(&body_str, &config) {
1230 Some(new_body) => new_body,
1231 None => match ::format_code_block(&body_str, &config) {
1232 Some(new_body) => new_body,
1233 None => return None,
1236 let new_body = wrap_str(new_body, config.max_width(), shape)?;
1238 // Indent the body since it is in a block.
1239 let indent_str = body_indent.to_string(&config);
1240 let mut new_body = LineClasses::new(new_body.trim_right())
1242 (String::new(), true),
1243 |(mut s, need_indent), (kind, ref l)| {
1244 if !l.is_empty() && need_indent {
1247 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1252 // Undo our replacement of macro variables.
1253 // FIXME: this could be *much* more efficient.
1254 for (old, new) in &substs {
1255 if old_body.find(new).is_some() {
1256 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1259 new_body = new_body.replace(new, old);
1263 result += new_body.trim();
1264 } else if !new_body.is_empty() {
1266 result += &new_body;
1267 result += &shape.indent.to_string(&config);
1276 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1278 /// # Expected syntax
1282 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1283 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1285 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1288 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1289 let mut result = String::with_capacity(1024);
1290 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1291 let nested_shape = shape
1292 .block_indent(context.config.tab_spaces())
1293 .with_max_width(context.config);
1295 result.push_str("lazy_static! {");
1296 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1298 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1299 match parser.$method($($arg,)*) {
1301 if parser.sess.span_diagnostic.has_errors() {
1302 parser.sess.span_diagnostic.reset_err_count();
1310 parser.sess.span_diagnostic.reset_err_count();
1316 while parser.token != Token::Eof {
1317 // Parse a `lazy_static!` item.
1318 let vis = ::utils::format_visibility(&parse_or!(parse_visibility, false));
1319 parser.eat_keyword(symbol::keywords::Static);
1320 parser.eat_keyword(symbol::keywords::Ref);
1321 let id = parse_or!(parse_ident);
1322 parser.eat(&Token::Colon);
1323 let ty = parse_or!(parse_ty);
1324 parser.eat(&Token::Eq);
1325 let expr = parse_or!(parse_expr);
1326 parser.eat(&Token::Semi);
1328 // Rewrite as a static item.
1329 let mut stmt = String::with_capacity(128);
1330 stmt.push_str(&format!(
1331 "{}static ref {}: {} =",
1334 ty.rewrite(context, nested_shape)?
1336 result.push_str(&::expr::rewrite_assign_rhs(
1340 nested_shape.sub_width(1)?,
1343 if parser.token != Token::Eof {
1344 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1348 result.push_str(&shape.indent.to_string_with_newline(context.config));