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::{ast, ptr};
26 use syntax::codemap::{BytePos, Span};
27 use syntax::parse::new_parser_from_tts;
28 use syntax::parse::parser::Parser;
29 use syntax::parse::token::{BinOpToken, DelimToken, Token};
30 use syntax::print::pprust;
32 use syntax::tokenstream::{Cursor, ThinTokenStream, TokenStream, TokenTree};
33 use syntax::util::ThinVec;
35 use codemap::SpanUtils;
36 use comment::{contains_comment, remove_trailing_white_spaces, CharClasses, FindUncommented,
38 use expr::rewrite_array;
39 use lists::{itemize_list, write_list, ListFormatting};
41 use rewrite::{Rewrite, RewriteContext};
42 use shape::{Indent, Shape};
44 use utils::{format_visibility, mk_sp, wrap_str};
46 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
48 // FIXME: use the enum from libsyntax?
49 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
56 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
57 pub enum MacroPosition {
65 fn opener(&self) -> &'static str {
67 MacroStyle::Parens => "(",
68 MacroStyle::Brackets => "[",
69 MacroStyle::Braces => "{",
76 Expr(ptr::P<ast::Expr>),
78 Pat(ptr::P<ast::Pat>),
79 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
80 Item(Option<ptr::P<ast::Item>>),
83 impl Rewrite for ast::Item {
84 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
85 let mut visitor = ::visitor::FmtVisitor::from_context(context);
86 visitor.block_indent = shape.indent;
87 visitor.last_pos = self.span().lo();
88 visitor.visit_item(self);
93 impl Rewrite for MacroArg {
94 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
96 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
97 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
98 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
99 MacroArg::Item(ref item) => item.as_ref().and_then(|item| item.rewrite(context, shape)),
104 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
105 macro_rules! parse_macro_arg {
106 ($macro_arg: ident, $parser: ident) => {
107 let mut cloned_parser = (*parser).clone();
108 match cloned_parser.$parser() {
110 if parser.sess.span_diagnostic.has_errors() {
111 parser.sess.span_diagnostic.reset_err_count();
113 // Parsing succeeded.
114 *parser = cloned_parser;
115 return Some(MacroArg::$macro_arg(x.clone()));
120 parser.sess.span_diagnostic.reset_err_count();
126 parse_macro_arg!(Expr, parse_expr);
127 parse_macro_arg!(Ty, parse_ty);
128 parse_macro_arg!(Pat, parse_pat);
129 parse_macro_arg!(Item, parse_item);
134 /// Rewrite macro name without using pretty-printer if possible.
135 fn rewrite_macro_name(path: &ast::Path, extra_ident: Option<ast::Ident>) -> String {
136 let name = if path.segments.len() == 1 {
137 // Avoid using pretty-printer in the common case.
138 format!("{}!", path.segments[0].identifier)
143 Some(ident) if ident != symbol::keywords::Invalid.ident() => format!("{} {}", name, ident),
148 pub fn rewrite_macro(
150 extra_ident: Option<ast::Ident>,
151 context: &RewriteContext,
153 position: MacroPosition,
154 ) -> Option<String> {
155 let context = &mut context.clone();
156 context.inside_macro = true;
157 if context.config.use_try_shorthand() {
158 if let Some(expr) = convert_try_mac(mac, context) {
159 context.inside_macro = false;
160 return expr.rewrite(context, shape);
164 let original_style = macro_style(mac, context);
166 let macro_name = rewrite_macro_name(&mac.node.path, extra_ident);
168 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
174 let ts: TokenStream = mac.node.stream();
175 let has_comment = contains_comment(context.snippet(mac.span));
176 if ts.is_empty() && !has_comment {
178 MacroStyle::Parens if position == MacroPosition::Item => {
179 Some(format!("{}();", macro_name))
181 MacroStyle::Parens => Some(format!("{}()", macro_name)),
182 MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
183 MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
186 // Format well-known macros which cannot be parsed as a valid AST.
187 // TODO: Maybe add more macros?
188 if macro_name == "lazy_static!" && !has_comment {
189 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
194 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
195 let mut arg_vec = Vec::new();
196 let mut vec_with_semi = false;
197 let mut trailing_comma = false;
199 if MacroStyle::Braces != style {
201 match parse_macro_arg(&mut parser) {
202 Some(arg) => arg_vec.push(arg),
203 None => return Some(context.snippet(mac.span).to_owned()),
210 // Try to parse `vec![expr; expr]`
211 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
213 if parser.token != Token::Eof {
214 match parse_macro_arg(&mut parser) {
218 if parser.token == Token::Eof && arg_vec.len() == 2 {
219 vec_with_semi = true;
223 None => return Some(context.snippet(mac.span).to_owned()),
227 return Some(context.snippet(mac.span).to_owned());
229 _ => return Some(context.snippet(mac.span).to_owned()),
234 if parser.token == Token::Eof {
235 trailing_comma = true;
242 MacroStyle::Parens => {
243 // Format macro invocation as function call, preserve the trailing
244 // comma because not all macros support them.
245 overflow::rewrite_with_parens(
248 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..],
251 context.config.width_heuristics().fn_call_width,
253 Some(SeparatorTactic::Always)
255 Some(SeparatorTactic::Never)
257 ).map(|rw| match position {
258 MacroPosition::Item => format!("{};", rw),
262 MacroStyle::Brackets => {
263 let mac_shape = shape.offset_left(macro_name.len())?;
264 // Handle special case: `vec![expr; expr]`
266 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
272 let total_overhead = lbr.len() + rbr.len() + 6;
273 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
274 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
275 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
276 if !lhs.contains('\n') && !rhs.contains('\n')
277 && lhs.len() + rhs.len() + total_overhead <= shape.width
279 Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
285 nested_shape.indent.to_string_with_newline(context.config),
287 nested_shape.indent.to_string_with_newline(context.config),
289 shape.indent.to_string_with_newline(context.config),
294 // If we are rewriting `vec!` macro or other special macros,
295 // then we can rewrite this as an usual array literal.
296 // Otherwise, we must preserve the original existence of trailing comma.
297 if FORCED_BRACKET_MACROS.contains(¯o_name.as_str()) {
298 context.inside_macro = false;
299 trailing_comma = false;
301 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
305 .span_after(mac.span, original_style.opener()),
306 mac.span.hi() - BytePos(1),
308 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..];
309 let rewrite = rewrite_array(arg_vec, sp, context, mac_shape, trailing_comma)?;
310 let comma = match position {
311 MacroPosition::Item => ";",
315 Some(format!("{}{}{}", macro_name, rewrite, comma))
318 MacroStyle::Braces => {
319 // Skip macro invocations with braces, for now.
320 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
325 pub fn rewrite_macro_def(
326 context: &RewriteContext,
331 vis: &ast::Visibility,
333 ) -> Option<String> {
334 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
335 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
339 let mut parser = MacroParser::new(def.stream().into_trees());
340 let parsed_def = match parser.parse() {
342 None => return snippet,
345 let mut result = if def.legacy {
346 String::from("macro_rules!")
348 format!("{}macro", format_visibility(vis))
352 result += &ident.name.as_str();
354 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
356 let arm_shape = if multi_branch_style {
358 .block_indent(context.config.tab_spaces())
359 .with_max_width(context.config)
364 let branch_items = itemize_list(
365 context.snippet_provider,
366 parsed_def.branches.iter(),
369 |branch| branch.span.lo(),
370 |branch| branch.span.hi(),
371 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
372 context.snippet_provider.span_after(span, "{"),
375 ).collect::<Vec<_>>();
377 let fmt = ListFormatting {
378 tactic: DefinitiveListTactic::Vertical,
379 separator: if def.legacy { ";" } else { "" },
380 trailing_separator: SeparatorTactic::Always,
381 separator_place: SeparatorPlace::Back,
383 ends_with_newline: true,
384 preserve_newline: true,
385 config: context.config,
388 if multi_branch_style {
390 result += &arm_shape.indent.to_string_with_newline(context.config);
393 result += write_list(&branch_items, &fmt)?.as_str();
395 if multi_branch_style {
396 result += &indent.to_string_with_newline(context.config);
403 fn register_metavariable(
404 map: &mut HashMap<String, String>,
409 let mut new_name = String::new();
410 let mut old_name = String::new();
413 for _ in 0..(dollar_count - 1) {
418 new_name.push_str(&name);
419 old_name.push_str(&name);
421 result.push_str(&new_name);
422 map.insert(old_name, new_name);
425 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
426 // aren't causing problems.
427 // This should also work for escaped `$` variables, where we leave earlier `$`s.
428 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
429 // Each substitution will require five or six extra bytes.
430 let mut result = String::with_capacity(input.len() + 64);
431 let mut substs = HashMap::new();
432 let mut dollar_count = 0;
433 let mut cur_name = String::new();
435 for (kind, c) in CharClasses::new(input.chars()) {
436 if kind != FullCodeCharKind::Normal {
440 } else if dollar_count == 0 {
442 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
443 // Terminates a name following one or more dollars.
444 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
449 } else if c == '(' && cur_name.is_empty() {
450 // FIXME: Support macro def with repeat.
452 } else if c.is_alphanumeric() {
457 if !cur_name.is_empty() {
458 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
461 debug!("replace_names `{}` {:?}", result, substs);
463 Some((result, substs))
466 #[derive(Debug, Clone)]
468 MetaVariable(ast::Ident, String),
472 Option<Box<ParsedMacroArg>>,
475 Delimited(DelimToken, Vec<ParsedMacroArg>),
476 Separator(String, String),
477 Other(String, String),
480 fn delim_token_to_str(
481 context: &RewriteContext,
482 delim_token: &DelimToken,
484 use_multiple_lines: bool,
485 ) -> (String, String) {
486 let (lhs, rhs) = match *delim_token {
487 DelimToken::Paren => ("(", ")"),
488 DelimToken::Bracket => ("[", "]"),
489 DelimToken::Brace => ("{", "}"),
490 DelimToken::NoDelim => ("", ""),
492 if use_multiple_lines {
493 let indent_str = shape.indent.to_string_with_newline(context.config);
494 let nested_indent_str = shape
496 .block_indent(context.config)
497 .to_string_with_newline(context.config);
499 format!("{}{}", lhs, nested_indent_str),
500 format!("{}{}", indent_str, rhs),
503 (lhs.to_owned(), rhs.to_owned())
508 fn starts_with_dollar(&self) -> bool {
510 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
515 fn ends_with_space(&self) -> bool {
517 MacroArgKind::Separator(..) => true,
524 context: &RewriteContext,
526 use_multiple_lines: bool,
527 ) -> Option<String> {
528 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
529 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false);
530 let inner = wrap_macro_args(context, args, shape)?;
531 if lhs.len() + inner.len() + rhs.len() <= shape.width {
532 return Some((lhs, inner, rhs));
535 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true);
536 let nested_shape = shape
537 .block_indent(context.config.tab_spaces())
538 .with_max_width(context.config);
539 let inner = wrap_macro_args(context, args, nested_shape)?;
540 Some((lhs, inner, rhs))
544 MacroArgKind::MetaVariable(ty, ref name) => {
545 Some(format!("${}: {}", name, ty.name.as_str()))
547 MacroArgKind::Repeat(ref delim_tok, ref args, ref another, ref tok) => {
548 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
549 let another = another
551 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
552 .unwrap_or("".to_owned());
553 let repeat_tok = pprust::token_to_string(tok);
555 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
557 MacroArgKind::Delimited(ref delim_tok, ref args) => {
558 rewrite_delimited_inner(delim_tok, args)
559 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
561 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
562 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
567 #[derive(Debug, Clone)]
568 struct ParsedMacroArg {
573 impl ParsedMacroArg {
576 context: &RewriteContext,
578 use_multiple_lines: bool,
579 ) -> Option<String> {
580 self.kind.rewrite(context, shape, use_multiple_lines)
584 struct MacroArgParser {
591 result: Vec<ParsedMacroArg>,
594 fn last_tok(tt: &TokenTree) -> Token {
596 TokenTree::Token(_, ref t) => t.clone(),
597 TokenTree::Delimited(_, ref d) => d.close_token(),
601 impl MacroArgParser {
602 pub fn new() -> MacroArgParser {
608 last_tok: Token::Eof,
609 start_tok: Token::Eof,
614 fn set_last_tok(&mut self, tok: &TokenTree) {
615 self.hi = tok.span().hi();
616 self.last_tok = last_tok(tok);
619 fn add_separator(&mut self) {
620 let prefix = if self.need_space_prefix() {
625 self.result.push(ParsedMacroArg {
626 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
627 span: mk_sp(self.lo, self.hi),
632 fn add_other(&mut self) {
633 let prefix = if self.need_space_prefix() {
638 self.result.push(ParsedMacroArg {
639 kind: MacroArgKind::Other(self.buf.clone(), prefix),
640 span: mk_sp(self.lo, self.hi),
645 fn add_meta_variable(&mut self, iter: &mut Cursor) {
647 Some(TokenTree::Token(sp, Token::Ident(ref ident))) => {
648 self.result.push(ParsedMacroArg {
649 kind: MacroArgKind::MetaVariable(ident.clone(), self.buf.clone()),
650 span: mk_sp(self.lo, sp.hi()),
660 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
661 if self.buf.is_empty() {
663 self.start_tok = t.clone();
664 } else if force_space_before(t) {
668 self.buf.push_str(&pprust::token_to_string(t));
671 fn need_space_prefix(&self) -> bool {
672 if self.result.is_empty() {
676 let last_arg = self.result.last().unwrap();
677 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
678 if ident_like(&self.start_tok) {
683 if force_space_before(&self.start_tok) {
690 /// Returns a collection of parsed macro def's arguments.
691 pub fn parse(mut self, tokens: ThinTokenStream) -> Vec<ParsedMacroArg> {
692 let mut iter = (tokens.into(): TokenStream).trees();
694 while let Some(ref tok) = iter.next() {
696 TokenTree::Token(sp, Token::Dollar) => {
697 // We always want to add a separator before meta variables.
698 if !self.buf.is_empty() {
699 self.add_separator();
702 // Start keeping the name of this metavariable in the buffer.
705 self.start_tok = Token::Dollar;
707 TokenTree::Token(_, Token::Colon) if self.is_arg => {
708 self.add_meta_variable(&mut iter);
710 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
711 TokenTree::Delimited(sp, ref delimited) => {
712 if !self.buf.is_empty() {
713 if next_space(&self.last_tok) == SpaceState::Always {
714 self.add_separator();
720 let mut parser = MacroArgParser::new();
722 let mut delimited_arg = parser.parse(delimited.tts.clone());
726 let mut buffer = String::new();
727 let mut first = false;
728 let mut lo = sp.lo();
730 while let Some(ref next_tok) = iter.next() {
731 self.set_last_tok(next_tok);
734 lo = next_tok.span().lo();
738 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
739 | TokenTree::Token(_, Token::Question)
740 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
743 TokenTree::Token(_, ref t) => {
744 buffer.push_str(&pprust::token_to_string(t))
750 let another = if buffer.trim().is_empty() {
753 Some(Box::new(ParsedMacroArg {
754 kind: MacroArgKind::Other(buffer, "".to_owned()),
755 span: mk_sp(lo, self.hi),
759 self.result.push(ParsedMacroArg {
760 kind: MacroArgKind::Repeat(
764 self.last_tok.clone(),
766 span: mk_sp(self.lo, self.hi),
769 self.result.push(ParsedMacroArg {
770 kind: MacroArgKind::Delimited(delimited.delim, delimited_arg),
777 self.set_last_tok(tok);
780 if !self.buf.is_empty() {
789 context: &RewriteContext,
790 args: &[ParsedMacroArg],
792 ) -> Option<String> {
793 wrap_macro_args_inner(context, args, shape, false)
794 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
797 fn wrap_macro_args_inner(
798 context: &RewriteContext,
799 args: &[ParsedMacroArg],
801 use_multiple_lines: bool,
802 ) -> Option<String> {
803 let mut result = String::with_capacity(128);
804 let mut iter = args.iter().peekable();
805 let indent_str = shape.indent.to_string_with_newline(context.config);
807 while let Some(ref arg) = iter.next() {
808 let nested_shape = if use_multiple_lines {
809 shape.with_max_width(context.config)
813 result.push_str(&arg.rewrite(context, nested_shape, use_multiple_lines)?);
815 if use_multiple_lines && arg.kind.ends_with_space() {
817 result.push_str(&indent_str);
818 } else if let Some(ref next_arg) = iter.peek() {
819 let space_before_dollar =
820 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
821 if space_before_dollar {
827 if !use_multiple_lines && result.len() >= shape.width {
834 // This is a bit sketchy. The token rules probably need tweaking, but it works
835 // for some common cases. I hope the basic logic is sufficient. Note that the
836 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
837 // and `(`/`)` have special meaning.
839 // We always try and format on one line.
840 // FIXME: Use multi-line when every thing does not fit on one line.
841 fn format_macro_args(
842 context: &RewriteContext,
843 toks: ThinTokenStream,
845 ) -> Option<String> {
846 let parsed_args = MacroArgParser::new().parse(toks);
847 wrap_macro_args(context, &parsed_args, shape)
850 // We should insert a space if the next token is a:
851 #[derive(Copy, Clone, PartialEq)]
855 Ident, // Or ident/literal-like thing.
859 fn force_space_before(tok: &Token) -> bool {
860 debug!("tok: force_space_before {:?}", tok);
880 | Token::Dollar => true,
881 Token::BinOp(bot) => bot != BinOpToken::Star,
886 fn ident_like(tok: &Token) -> bool {
888 Token::Ident(_) | Token::Literal(..) | Token::Lifetime(_) => true,
893 fn next_space(tok: &Token) -> SpaceState {
894 debug!("next_space: {:?}", tok);
908 | Token::BinOp(_) => SpaceState::Punctuation,
913 | Token::OpenDelim(_)
914 | Token::CloseDelim(_)
915 | Token::Whitespace => SpaceState::Never,
917 Token::Literal(..) | Token::Ident(_) | Token::Lifetime(_) => SpaceState::Ident,
919 _ => SpaceState::Always,
923 /// Tries to convert a macro use into a short hand try expression. Returns None
924 /// when the macro is not an instance of try! (or parsing the inner expression
926 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
927 if &format!("{}", mac.node.path)[..] == "try" {
928 let ts: TokenStream = mac.node.tts.clone().into();
929 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
932 id: ast::NodeId::new(0), // dummy value
933 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
934 span: mac.span, // incorrect span, but shouldn't matter too much
935 attrs: ThinVec::new(),
942 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
943 let snippet = context.snippet(mac.span);
944 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
945 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
946 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
948 if paren_pos < bracket_pos && paren_pos < brace_pos {
950 } else if bracket_pos < brace_pos {
957 /// Indent each line according to the specified `indent`.
985 fn indent_macro_snippet(
986 context: &RewriteContext,
989 ) -> Option<String> {
990 let mut lines = macro_str.lines();
991 let first_line = lines.next().map(|s| s.trim_right())?;
992 let mut trimmed_lines = Vec::with_capacity(16);
994 let min_prefix_space_width = lines
996 let prefix_space_width = if is_empty_line(line) {
999 Some(get_prefix_space_width(context, line))
1001 trimmed_lines.push((line.trim(), prefix_space_width));
1007 String::from(first_line) + "\n"
1010 .map(|&(line, prefix_space_width)| match prefix_space_width {
1011 Some(original_indent_width) => {
1012 let new_indent_width = indent.width()
1013 + original_indent_width
1014 .checked_sub(min_prefix_space_width)
1016 let new_indent = Indent::from_width(context.config, new_indent_width);
1017 format!("{}{}", new_indent.to_string(context.config), line.trim())
1019 None => String::new(),
1021 .collect::<Vec<_>>()
1026 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1028 for c in s.chars() {
1031 '\t' => width += context.config.tab_spaces(),
1038 fn is_empty_line(s: &str) -> bool {
1039 s.is_empty() || s.chars().all(char::is_whitespace)
1042 // A very simple parser that just parses a macros 2.0 definition into its branches.
1043 // Currently we do not attempt to parse any further than that.
1045 struct MacroParser {
1050 // (`(` ... `)` `=>` `{` ... `}`)*
1051 fn parse(&mut self) -> Option<Macro> {
1052 let mut branches = vec![];
1053 while self.toks.look_ahead(1).is_some() {
1054 branches.push(self.parse_branch()?);
1057 Some(Macro { branches })
1060 // `(` ... `)` `=>` `{` ... `}`
1061 fn parse_branch(&mut self) -> Option<MacroBranch> {
1062 let tok = self.toks.next()?;
1063 let (lo, args_paren_kind) = match tok {
1064 TokenTree::Token(..) => return None,
1065 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
1067 let args = tok.joint().into();
1068 match self.toks.next()? {
1069 TokenTree::Token(_, Token::FatArrow) => {}
1072 let (mut hi, body) = match self.toks.next()? {
1073 TokenTree::Token(..) => return None,
1074 TokenTree::Delimited(sp, _) => {
1075 let data = sp.data();
1078 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1082 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1087 span: mk_sp(lo, hi),
1095 // A parsed macros 2.0 macro definition.
1097 branches: Vec<MacroBranch>,
1100 // FIXME: it would be more efficient to use references to the token streams
1101 // rather than clone them, if we can make the borrowing work out.
1102 struct MacroBranch {
1104 args_paren_kind: DelimToken,
1105 args: ThinTokenStream,
1112 context: &RewriteContext,
1114 multi_branch_style: bool,
1115 ) -> Option<String> {
1116 // Only attempt to format function-like macros.
1117 if self.args_paren_kind != DelimToken::Paren {
1118 // FIXME(#1539): implement for non-sugared macros.
1123 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1125 if multi_branch_style {
1129 // The macro body is the most interesting part. It might end up as various
1130 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1131 // parsed as regular Rust code (and note that these can be escaped using
1132 // `$$`). We'll try and format like an AST node, but we'll substitute
1133 // variables for new names with the same length first.
1135 let old_body = context.snippet(self.body).trim();
1136 let (body_str, substs) = replace_names(old_body)?;
1138 let mut config = context.config.clone();
1139 config.set().hide_parse_errors(true);
1143 let has_block_body = old_body.starts_with('{');
1145 let body_indent = if has_block_body {
1148 // We'll hack the indent below, take this into account when formatting,
1149 let body_indent = shape.indent.block_indent(&config);
1150 let new_width = config.max_width() - body_indent.width();
1151 config.set().max_width(new_width);
1155 // First try to format as items, then as statements.
1156 let new_body = match ::format_snippet(&body_str, &config) {
1157 Some(new_body) => new_body,
1158 None => match ::format_code_block(&body_str, &config) {
1159 Some(new_body) => new_body,
1160 None => return None,
1163 let new_body = wrap_str(new_body, config.max_width(), shape)?;
1165 // Indent the body since it is in a block.
1166 let indent_str = body_indent.to_string(&config);
1167 let mut new_body = new_body
1170 .fold(String::new(), |mut s, l| {
1177 // Undo our replacement of macro variables.
1178 // FIXME: this could be *much* more efficient.
1179 for (old, new) in &substs {
1180 if old_body.find(new).is_some() {
1181 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1184 new_body = new_body.replace(new, old);
1188 result += new_body.trim();
1189 } else if !new_body.is_empty() {
1191 result += &new_body;
1192 result += &shape.indent.to_string(&config);
1201 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1203 /// # Expected syntax
1207 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1208 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1210 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1213 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1214 let mut result = String::with_capacity(1024);
1215 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1216 let nested_shape = shape.block_indent(context.config.tab_spaces());
1218 result.push_str("lazy_static! {");
1219 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1221 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1222 match parser.$method($($arg,)*) {
1224 if parser.sess.span_diagnostic.has_errors() {
1225 parser.sess.span_diagnostic.reset_err_count();
1233 parser.sess.span_diagnostic.reset_err_count();
1239 while parser.token != Token::Eof {
1240 // Parse a `lazy_static!` item.
1241 let vis = ::utils::format_visibility(&parse_or!(parse_visibility, false));
1242 parser.eat_keyword(symbol::keywords::Static);
1243 parser.eat_keyword(symbol::keywords::Ref);
1244 let id = parse_or!(parse_ident);
1245 parser.eat(&Token::Colon);
1246 let ty = parse_or!(parse_ty);
1247 parser.eat(&Token::Eq);
1248 let expr = parse_or!(parse_expr);
1249 parser.eat(&Token::Semi);
1251 // Rewrite as a static item.
1252 let mut stmt = String::with_capacity(128);
1253 stmt.push_str(&format!(
1254 "{}static ref {}: {} =",
1257 ty.rewrite(context, nested_shape)?
1259 result.push_str(&::expr::rewrite_assign_rhs(
1263 nested_shape.sub_width(1)?,
1266 if parser.token != Token::Eof {
1267 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1271 result.push_str(&shape.indent.to_string_with_newline(context.config));