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::parse::new_parser_from_tts;
26 use syntax::parse::parser::Parser;
27 use syntax::parse::token::{BinOpToken, DelimToken, Token};
28 use syntax::print::pprust;
29 use syntax::source_map::{BytePos, Span};
31 use syntax::tokenstream::{Cursor, ThinTokenStream, TokenStream, TokenTree};
33 use syntax::{ast, ptr};
35 use comment::{contains_comment, CharClasses, FindUncommented, FullCodeCharKind, LineClasses};
36 use expr::rewrite_array;
37 use lists::{itemize_list, write_list, ListFormatting};
39 use rewrite::{Rewrite, RewriteContext};
40 use shape::{Indent, Shape};
41 use source_map::SpanUtils;
43 use utils::{format_visibility, mk_sp, remove_trailing_white_spaces, rewrite_ident, wrap_str};
44 use visitor::FmtVisitor;
46 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
48 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
49 pub enum MacroPosition {
58 Expr(ptr::P<ast::Expr>),
60 Pat(ptr::P<ast::Pat>),
61 Item(ptr::P<ast::Item>),
65 fn is_item(&self) -> bool {
67 MacroArg::Item(..) => true,
73 impl Rewrite for ast::Item {
74 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
75 let mut visitor = ::visitor::FmtVisitor::from_context(context);
76 visitor.block_indent = shape.indent;
77 visitor.last_pos = self.span().lo();
78 visitor.visit_item(self);
79 Some(visitor.buffer.to_owned())
83 impl Rewrite for MacroArg {
84 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
86 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
87 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
88 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
89 MacroArg::Item(ref item) => item.rewrite(context, shape),
94 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
95 macro_rules! parse_macro_arg {
96 ($macro_arg:ident, $parser:ident, $f:expr) => {
97 let mut cloned_parser = (*parser).clone();
98 match cloned_parser.$parser() {
100 if parser.sess.span_diagnostic.has_errors() {
101 parser.sess.span_diagnostic.reset_err_count();
103 // Parsing succeeded.
104 *parser = cloned_parser;
105 return Some(MacroArg::$macro_arg($f(x)?));
110 parser.sess.span_diagnostic.reset_err_count();
116 parse_macro_arg!(Expr, parse_expr, |x: ptr::P<ast::Expr>| Some(x));
117 parse_macro_arg!(Ty, parse_ty, |x: ptr::P<ast::Ty>| Some(x));
118 parse_macro_arg!(Pat, parse_pat, |x: ptr::P<ast::Pat>| Some(x));
119 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
120 parse_macro_arg!(Item, parse_item, |x: Option<ptr::P<ast::Item>>| x);
125 /// Rewrite macro name without using pretty-printer if possible.
126 fn rewrite_macro_name(
127 context: &RewriteContext,
129 extra_ident: Option<ast::Ident>,
131 let name = if path.segments.len() == 1 {
132 // Avoid using pretty-printer in the common case.
133 format!("{}!", rewrite_ident(context, path.segments[0].ident))
138 Some(ident) if ident != symbol::keywords::Invalid.ident() => format!("{} {}", name, ident),
143 // Use this on failing to format the macro call.
144 fn return_original_snippet_with_failure_marked(
145 context: &RewriteContext,
147 ) -> Option<String> {
148 context.macro_rewrite_failure.replace(true);
149 Some(context.snippet(span).to_owned())
152 struct InsideMacroGuard<'a> {
153 context: &'a RewriteContext<'a>,
157 impl<'a> InsideMacroGuard<'a> {
158 fn inside_macro_context(context: &'a RewriteContext) -> InsideMacroGuard<'a> {
159 let is_nested = context.inside_macro.replace(true);
160 InsideMacroGuard { context, is_nested }
164 impl<'a> Drop for InsideMacroGuard<'a> {
166 self.context.inside_macro.replace(self.is_nested);
170 pub fn rewrite_macro(
172 extra_ident: Option<ast::Ident>,
173 context: &RewriteContext,
175 position: MacroPosition,
176 ) -> Option<String> {
177 let guard = InsideMacroGuard::inside_macro_context(context);
178 let result = rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
179 if result.is_none() {
180 context.macro_rewrite_failure.replace(true);
185 pub fn rewrite_macro_inner(
187 extra_ident: Option<ast::Ident>,
188 context: &RewriteContext,
190 position: MacroPosition,
191 is_nested_macro: bool,
192 ) -> Option<String> {
193 if context.config.use_try_shorthand() {
194 if let Some(expr) = convert_try_mac(mac, context) {
195 context.inside_macro.replace(false);
196 return expr.rewrite(context, shape);
200 let original_style = macro_style(mac, context);
202 let macro_name = rewrite_macro_name(context, &mac.node.path, extra_ident);
204 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) && !is_nested_macro {
210 let ts: TokenStream = mac.node.stream();
211 let has_comment = contains_comment(context.snippet(mac.span));
212 if ts.is_empty() && !has_comment {
214 DelimToken::Paren if position == MacroPosition::Item => {
215 Some(format!("{}();", macro_name))
217 DelimToken::Paren => Some(format!("{}()", macro_name)),
218 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
219 DelimToken::Brace => Some(format!("{}{{}}", macro_name)),
223 // Format well-known macros which cannot be parsed as a valid AST.
224 if macro_name == "lazy_static!" && !has_comment {
225 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
230 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
231 let mut arg_vec = Vec::new();
232 let mut vec_with_semi = false;
233 let mut trailing_comma = false;
235 if DelimToken::Brace != style {
237 match parse_macro_arg(&mut parser) {
238 Some(arg) => arg_vec.push(arg),
239 None => return return_original_snippet_with_failure_marked(context, mac.span),
246 // Try to parse `vec![expr; expr]`
247 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
249 if parser.token != Token::Eof {
250 match parse_macro_arg(&mut parser) {
254 if parser.token == Token::Eof && arg_vec.len() == 2 {
255 vec_with_semi = true;
260 return return_original_snippet_with_failure_marked(
267 return return_original_snippet_with_failure_marked(context, mac.span);
269 _ if arg_vec.last().map_or(false, MacroArg::is_item) => continue,
270 _ => return return_original_snippet_with_failure_marked(context, mac.span),
275 if parser.token == Token::Eof {
276 trailing_comma = true;
282 if !arg_vec.is_empty() && arg_vec.iter().all(MacroArg::is_item) {
283 return rewrite_macro_with_items(
295 DelimToken::Paren => {
296 // Format macro invocation as function call, preserve the trailing
297 // comma because not all macros support them.
298 overflow::rewrite_with_parens(
304 context.config.width_heuristics().fn_call_width,
306 Some(SeparatorTactic::Always)
308 Some(SeparatorTactic::Never)
311 .map(|rw| match position {
312 MacroPosition::Item => format!("{};", rw),
316 DelimToken::Bracket => {
317 // Handle special case: `vec![expr; expr]`
319 let mac_shape = shape.offset_left(macro_name.len())?;
320 // 8 = `vec![]` + `; `
321 let total_overhead = 8;
322 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
323 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
324 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
325 if !lhs.contains('\n')
326 && !rhs.contains('\n')
327 && lhs.len() + rhs.len() + total_overhead <= shape.width
329 Some(format!("{}[{}; {}]", macro_name, lhs, rhs))
334 nested_shape.indent.to_string_with_newline(context.config),
336 nested_shape.indent.to_string_with_newline(context.config),
338 shape.indent.to_string_with_newline(context.config),
342 // If we are rewriting `vec!` macro or other special macros,
343 // then we can rewrite this as an usual array literal.
344 // Otherwise, we must preserve the original existence of trailing comma.
345 let macro_name = ¯o_name.as_str();
346 let mut force_trailing_comma = if trailing_comma {
347 Some(SeparatorTactic::Always)
349 Some(SeparatorTactic::Never)
351 if FORCED_BRACKET_MACROS.contains(macro_name) && !is_nested_macro {
352 context.inside_macro.replace(false);
353 if context.use_block_indent() {
354 force_trailing_comma = Some(SeparatorTactic::Vertical);
357 let rewrite = rewrite_array(
363 force_trailing_comma,
364 Some(original_style),
366 let comma = match position {
367 MacroPosition::Item => ";",
371 Some(format!("{}{}", rewrite, comma))
374 DelimToken::Brace => {
375 // Skip macro invocations with braces, for now.
376 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
382 pub fn rewrite_macro_def(
383 context: &RewriteContext,
388 vis: &ast::Visibility,
390 ) -> Option<String> {
391 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
392 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
396 let mut parser = MacroParser::new(def.stream().into_trees());
397 let parsed_def = match parser.parse() {
399 None => return snippet,
402 let mut result = if def.legacy {
403 String::from("macro_rules!")
405 format!("{}macro", format_visibility(context, vis))
409 result += rewrite_ident(context, ident);
411 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
413 let arm_shape = if multi_branch_style {
415 .block_indent(context.config.tab_spaces())
416 .with_max_width(context.config)
421 let branch_items = itemize_list(
422 context.snippet_provider,
423 parsed_def.branches.iter(),
426 |branch| branch.span.lo(),
427 |branch| branch.span.hi(),
428 |branch| match branch.rewrite(context, arm_shape, multi_branch_style) {
430 // if the rewrite returned None because a macro could not be rewritten, then return the
432 None if *context.macro_rewrite_failure.borrow() => {
433 Some(context.snippet(branch.body).trim().to_string())
437 context.snippet_provider.span_after(span, "{"),
441 .collect::<Vec<_>>();
443 let fmt = ListFormatting::new(arm_shape, context.config)
444 .separator(if def.legacy { ";" } else { "" })
445 .trailing_separator(SeparatorTactic::Always)
446 .preserve_newline(true);
448 if multi_branch_style {
450 result += &arm_shape.indent.to_string_with_newline(context.config);
453 match write_list(&branch_items, &fmt) {
454 Some(ref s) => result += s,
455 None => return snippet,
458 if multi_branch_style {
459 result += &indent.to_string_with_newline(context.config);
466 fn register_metavariable(
467 map: &mut HashMap<String, String>,
472 let mut new_name = String::new();
473 let mut old_name = String::new();
476 for _ in 0..(dollar_count - 1) {
481 new_name.push_str(&name);
482 old_name.push_str(&name);
484 result.push_str(&new_name);
485 map.insert(old_name, new_name);
488 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
489 // aren't causing problems.
490 // This should also work for escaped `$` variables, where we leave earlier `$`s.
491 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
492 // Each substitution will require five or six extra bytes.
493 let mut result = String::with_capacity(input.len() + 64);
494 let mut substs = HashMap::new();
495 let mut dollar_count = 0;
496 let mut cur_name = String::new();
498 for (kind, c) in CharClasses::new(input.chars()) {
499 if kind != FullCodeCharKind::Normal {
503 } else if dollar_count == 0 {
505 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
506 // Terminates a name following one or more dollars.
507 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
512 } else if c == '(' && cur_name.is_empty() {
513 // FIXME: Support macro def with repeat.
515 } else if c.is_alphanumeric() || c == '_' {
520 if !cur_name.is_empty() {
521 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
524 debug!("replace_names `{}` {:?}", result, substs);
526 Some((result, substs))
529 #[derive(Debug, Clone)]
532 MetaVariable(ast::Ident, String),
533 /// e.g. `$($foo: expr),*`
535 /// `()`, `[]` or `{}`.
537 /// Inner arguments inside delimiters.
539 /// Something after the closing delimiter and the repeat token, if available.
540 Option<Box<ParsedMacroArg>>,
541 /// The repeat token. This could be one of `*`, `+` or `?`.
544 /// e.g. `[derive(Debug)]`
545 Delimited(DelimToken, Vec<ParsedMacroArg>),
546 /// A possible separator. e.g. `,` or `;`.
547 Separator(String, String),
548 /// Other random stuff that does not fit to other kinds.
549 /// e.g. `== foo` in `($x: expr == foo)`.
550 Other(String, String),
553 fn delim_token_to_str(
554 context: &RewriteContext,
555 delim_token: DelimToken,
557 use_multiple_lines: bool,
558 inner_is_empty: bool,
559 ) -> (String, String) {
560 let (lhs, rhs) = match delim_token {
561 DelimToken::Paren => ("(", ")"),
562 DelimToken::Bracket => ("[", "]"),
563 DelimToken::Brace => {
564 if inner_is_empty || use_multiple_lines {
570 DelimToken::NoDelim => ("", ""),
572 if use_multiple_lines {
573 let indent_str = shape.indent.to_string_with_newline(context.config);
574 let nested_indent_str = shape
576 .block_indent(context.config)
577 .to_string_with_newline(context.config);
579 format!("{}{}", lhs, nested_indent_str),
580 format!("{}{}", indent_str, rhs),
583 (lhs.to_owned(), rhs.to_owned())
588 fn starts_with_brace(&self) -> bool {
590 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
591 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
596 fn starts_with_dollar(&self) -> bool {
598 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
603 fn ends_with_space(&self) -> bool {
605 MacroArgKind::Separator(..) => true,
610 fn has_meta_var(&self) -> bool {
612 MacroArgKind::MetaVariable(..) => true,
613 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
620 context: &RewriteContext,
622 use_multiple_lines: bool,
623 ) -> Option<String> {
624 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
625 let inner = wrap_macro_args(context, args, shape)?;
626 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
627 if lhs.len() + inner.len() + rhs.len() <= shape.width {
628 return Some((lhs, inner, rhs));
631 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
632 let nested_shape = shape
633 .block_indent(context.config.tab_spaces())
634 .with_max_width(context.config);
635 let inner = wrap_macro_args(context, args, nested_shape)?;
636 Some((lhs, inner, rhs))
640 MacroArgKind::MetaVariable(ty, ref name) => {
641 Some(format!("${}:{}", name, ty.name.as_str()))
643 MacroArgKind::Repeat(delim_tok, ref args, ref another, ref tok) => {
644 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
645 let another = another
647 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
648 .unwrap_or_else(|| "".to_owned());
649 let repeat_tok = pprust::token_to_string(tok);
651 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
653 MacroArgKind::Delimited(delim_tok, ref args) => {
654 rewrite_delimited_inner(delim_tok, args)
655 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
657 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
658 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
663 #[derive(Debug, Clone)]
664 struct ParsedMacroArg {
669 impl ParsedMacroArg {
672 context: &RewriteContext,
674 use_multiple_lines: bool,
675 ) -> Option<String> {
676 self.kind.rewrite(context, shape, use_multiple_lines)
680 /// Parses macro arguments on macro def.
681 struct MacroArgParser {
682 /// Holds either a name of the next metavariable, a separator or a junk.
684 /// The start position on the current buffer.
686 /// The first token of the current buffer.
688 /// Set to true if we are parsing a metavariable or a repeat.
690 /// The position of the last token.
692 /// The last token parsed.
694 /// Holds the parsed arguments.
695 result: Vec<ParsedMacroArg>,
698 fn last_tok(tt: &TokenTree) -> Token {
700 TokenTree::Token(_, ref t) => t.clone(),
701 TokenTree::Delimited(_, ref d) => d.close_token(),
705 impl MacroArgParser {
706 pub fn new() -> MacroArgParser {
712 last_tok: Token::Eof,
713 start_tok: Token::Eof,
718 fn set_last_tok(&mut self, tok: &TokenTree) {
719 self.hi = tok.span().hi();
720 self.last_tok = last_tok(tok);
723 fn add_separator(&mut self) {
724 let prefix = if self.need_space_prefix() {
729 self.result.push(ParsedMacroArg {
730 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
731 span: mk_sp(self.lo, self.hi),
736 fn add_other(&mut self) {
737 let prefix = if self.need_space_prefix() {
742 self.result.push(ParsedMacroArg {
743 kind: MacroArgKind::Other(self.buf.clone(), prefix),
744 span: mk_sp(self.lo, self.hi),
749 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
751 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
752 self.result.push(ParsedMacroArg {
753 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
754 span: mk_sp(self.lo, sp.hi()),
758 self.is_meta_var = false;
765 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
766 self.result.push(ParsedMacroArg {
767 kind: MacroArgKind::Delimited(delim, inner),
775 inner: Vec<ParsedMacroArg>,
780 let mut buffer = String::new();
781 let mut first = false;
782 let mut lo = span.lo();
783 let mut hi = span.hi();
785 // Parse '*', '+' or '?.
787 self.set_last_tok(&tok);
790 lo = tok.span().lo();
794 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
795 | TokenTree::Token(_, Token::Question)
796 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
799 TokenTree::Token(sp, ref t) => {
800 buffer.push_str(&pprust::token_to_string(t));
807 // There could be some random stuff between ')' and '*', '+' or '?'.
808 let another = if buffer.trim().is_empty() {
811 Some(Box::new(ParsedMacroArg {
812 kind: MacroArgKind::Other(buffer, "".to_owned()),
817 self.result.push(ParsedMacroArg {
818 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
819 span: mk_sp(self.lo, self.hi),
824 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
825 if self.buf.is_empty() {
827 self.start_tok = t.clone();
829 let needs_space = match next_space(&self.last_tok) {
830 SpaceState::Ident => ident_like(t),
831 SpaceState::Punctuation => !ident_like(t),
832 SpaceState::Always => true,
833 SpaceState::Never => false,
835 if force_space_before(t) || needs_space {
840 self.buf.push_str(&pprust::token_to_string(t));
843 fn need_space_prefix(&self) -> bool {
844 if self.result.is_empty() {
848 let last_arg = self.result.last().unwrap();
849 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
850 if ident_like(&self.start_tok) {
853 if self.start_tok == Token::Colon {
858 if force_space_before(&self.start_tok) {
865 /// Returns a collection of parsed macro def's arguments.
866 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
867 let stream: TokenStream = tokens.into();
868 let mut iter = stream.trees();
870 while let Some(ref tok) = iter.next() {
872 TokenTree::Token(sp, Token::Dollar) => {
873 // We always want to add a separator before meta variables.
874 if !self.buf.is_empty() {
875 self.add_separator();
878 // Start keeping the name of this metavariable in the buffer.
879 self.is_meta_var = true;
881 self.start_tok = Token::Dollar;
883 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
884 self.add_meta_variable(&mut iter)?;
886 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
887 TokenTree::Delimited(delimited_span, delimited) => {
888 if !self.buf.is_empty() {
889 if next_space(&self.last_tok) == SpaceState::Always {
890 self.add_separator();
896 // Parse the stuff inside delimiters.
897 let mut parser = MacroArgParser::new();
898 parser.lo = delimited_span.open.lo();
899 let delimited_arg = parser.parse(delimited.tts.clone())?;
901 let span = delimited_span.entire();
902 if self.is_meta_var {
903 self.add_repeat(delimited_arg, delimited.delim, &mut iter, span)?;
904 self.is_meta_var = false;
906 self.add_delimited(delimited_arg, delimited.delim, span);
911 self.set_last_tok(tok);
914 // We are left with some stuff in the buffer. Since there is nothing
915 // left to separate, add this as `Other`.
916 if !self.buf.is_empty() {
925 context: &RewriteContext,
926 args: &[ParsedMacroArg],
928 ) -> Option<String> {
929 wrap_macro_args_inner(context, args, shape, false)
930 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
933 fn wrap_macro_args_inner(
934 context: &RewriteContext,
935 args: &[ParsedMacroArg],
937 use_multiple_lines: bool,
938 ) -> Option<String> {
939 let mut result = String::with_capacity(128);
940 let mut iter = args.iter().peekable();
941 let indent_str = shape.indent.to_string_with_newline(context.config);
943 while let Some(ref arg) = iter.next() {
944 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
946 if use_multiple_lines
947 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
949 if arg.kind.ends_with_space() {
952 result.push_str(&indent_str);
953 } else if let Some(ref next_arg) = iter.peek() {
954 let space_before_dollar =
955 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
956 let space_before_brace = next_arg.kind.starts_with_brace();
957 if space_before_dollar || space_before_brace {
963 if !use_multiple_lines && result.len() >= shape.width {
970 // This is a bit sketchy. The token rules probably need tweaking, but it works
971 // for some common cases. I hope the basic logic is sufficient. Note that the
972 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
973 // and `(`/`)` have special meaning.
975 // We always try and format on one line.
976 // FIXME: Use multi-line when every thing does not fit on one line.
977 fn format_macro_args(
978 context: &RewriteContext,
979 toks: ThinTokenStream,
981 ) -> Option<String> {
982 if !context.config.format_macro_matchers() {
983 let token_stream: TokenStream = toks.into();
984 let span = span_for_token_stream(&token_stream);
985 return Some(match span {
986 Some(span) => context.snippet(span).to_owned(),
987 None => String::new(),
990 let parsed_args = MacroArgParser::new().parse(toks)?;
991 wrap_macro_args(context, &parsed_args, shape)
994 fn span_for_token_stream(token_stream: &TokenStream) -> Option<Span> {
995 token_stream.trees().next().map(|tt| tt.span())
998 // We should insert a space if the next token is a:
999 #[derive(Copy, Clone, PartialEq)]
1003 Ident, // Or ident/literal-like thing.
1007 fn force_space_before(tok: &Token) -> bool {
1008 debug!("tok: force_space_before {:?}", tok);
1029 | Token::Dollar => true,
1034 fn ident_like(tok: &Token) -> bool {
1036 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
1041 fn next_space(tok: &Token) -> SpaceState {
1042 debug!("next_space: {:?}", tok);
1046 | Token::BinOp(BinOpToken::And)
1055 | Token::Question => SpaceState::Punctuation,
1060 | Token::OpenDelim(_)
1061 | Token::CloseDelim(_)
1062 | Token::Whitespace => SpaceState::Never,
1064 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
1066 _ => SpaceState::Always,
1070 /// Tries to convert a macro use into a short hand try expression. Returns None
1071 /// when the macro is not an instance of try! (or parsing the inner expression
1073 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
1074 if &mac.node.path.to_string() == "try" {
1075 let ts: TokenStream = mac.node.tts.clone().into();
1076 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1079 id: ast::NodeId::new(0), // dummy value
1080 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1081 span: mac.span, // incorrect span, but shouldn't matter too much
1082 attrs: ThinVec::new(),
1089 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1090 let snippet = context.snippet(mac.span);
1091 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1092 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1093 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1095 if paren_pos < bracket_pos && paren_pos < brace_pos {
1097 } else if bracket_pos < brace_pos {
1104 /// Indent each line according to the specified `indent`.
1132 fn indent_macro_snippet(
1133 context: &RewriteContext,
1136 ) -> Option<String> {
1137 let mut lines = LineClasses::new(macro_str);
1138 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1139 let mut trimmed_lines = Vec::with_capacity(16);
1141 let mut veto_trim = false;
1142 let min_prefix_space_width = lines
1143 .filter_map(|(kind, line)| {
1144 let mut trimmed = true;
1145 let prefix_space_width = if is_empty_line(&line) {
1148 Some(get_prefix_space_width(context, &line))
1151 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1152 veto_trim = kind.is_string() && !line.ends_with('\\');
1156 line.trim().to_owned()
1158 trimmed_lines.push((trimmed, line, prefix_space_width));
1160 // when computing the minimum, do not consider lines within a string
1162 FullCodeCharKind::InString | FullCodeCharKind::EndString => None,
1163 _ => prefix_space_width,
1174 |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
1175 _ if !trimmed => line.to_owned(),
1176 Some(original_indent_width) => {
1177 let new_indent_width = indent.width()
1178 + original_indent_width.saturating_sub(min_prefix_space_width);
1179 let new_indent = Indent::from_width(context.config, new_indent_width);
1180 format!("{}{}", new_indent.to_string(context.config), line)
1182 None => String::new(),
1185 .collect::<Vec<_>>()
1190 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1192 for c in s.chars() {
1195 '\t' => width += context.config.tab_spaces(),
1202 fn is_empty_line(s: &str) -> bool {
1203 s.is_empty() || s.chars().all(char::is_whitespace)
1206 // A very simple parser that just parses a macros 2.0 definition into its branches.
1207 // Currently we do not attempt to parse any further than that.
1209 struct MacroParser {
1214 // (`(` ... `)` `=>` `{` ... `}`)*
1215 fn parse(&mut self) -> Option<Macro> {
1216 let mut branches = vec![];
1217 while self.toks.look_ahead(1).is_some() {
1218 branches.push(self.parse_branch()?);
1221 Some(Macro { branches })
1224 // `(` ... `)` `=>` `{` ... `}`
1225 fn parse_branch(&mut self) -> Option<MacroBranch> {
1226 let tok = self.toks.next()?;
1227 let (lo, args_paren_kind) = match tok {
1228 TokenTree::Token(..) => return None,
1229 TokenTree::Delimited(delimited_span, ref d) => (delimited_span.open.lo(), d.delim),
1231 let args = tok.joint().into();
1232 match self.toks.next()? {
1233 TokenTree::Token(_, Token::FatArrow) => {}
1236 let (mut hi, body, whole_body) = match self.toks.next()? {
1237 TokenTree::Token(..) => return None,
1238 TokenTree::Delimited(delimited_span, _) => {
1239 let data = delimited_span.entire().data();
1242 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1243 delimited_span.entire(),
1247 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1252 span: mk_sp(lo, hi),
1261 // A parsed macros 2.0 macro definition.
1263 branches: Vec<MacroBranch>,
1266 // FIXME: it would be more efficient to use references to the token streams
1267 // rather than clone them, if we can make the borrowing work out.
1268 struct MacroBranch {
1270 args_paren_kind: DelimToken,
1271 args: ThinTokenStream,
1279 context: &RewriteContext,
1281 multi_branch_style: bool,
1282 ) -> Option<String> {
1283 // Only attempt to format function-like macros.
1284 if self.args_paren_kind != DelimToken::Paren {
1285 // FIXME(#1539): implement for non-sugared macros.
1290 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1292 if multi_branch_style {
1296 if !context.config.format_macro_bodies() {
1298 result += context.snippet(self.whole_body);
1299 return Some(result);
1302 // The macro body is the most interesting part. It might end up as various
1303 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1304 // parsed as regular Rust code (and note that these can be escaped using
1305 // `$$`). We'll try and format like an AST node, but we'll substitute
1306 // variables for new names with the same length first.
1308 let old_body = context.snippet(self.body).trim();
1309 let (body_str, substs) = replace_names(old_body)?;
1310 let has_block_body = old_body.starts_with('{');
1312 let mut config = context.config.clone();
1313 config.set().hide_parse_errors(true);
1317 let body_indent = if has_block_body {
1320 shape.indent.block_indent(&config)
1322 let new_width = config.max_width() - body_indent.width();
1323 config.set().max_width(new_width);
1325 // First try to format as items, then as statements.
1326 let new_body_snippet = match ::format_snippet(&body_str, &config) {
1327 Some(new_body) => new_body,
1329 let new_width = new_width + config.tab_spaces();
1330 config.set().max_width(new_width);
1331 match ::format_code_block(&body_str, &config) {
1332 Some(new_body) => new_body,
1333 None => return None,
1337 let new_body = wrap_str(
1338 new_body_snippet.snippet.to_string(),
1343 // Indent the body since it is in a block.
1344 let indent_str = body_indent.to_string(&config);
1345 let mut new_body = LineClasses::new(new_body.trim_right())
1348 (String::new(), true),
1349 |(mut s, need_indent), (i, (kind, ref l))| {
1352 && !new_body_snippet.is_line_non_formatted(i + 1)
1356 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1361 // Undo our replacement of macro variables.
1362 // FIXME: this could be *much* more efficient.
1363 for (old, new) in &substs {
1364 if old_body.find(new).is_some() {
1365 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1368 new_body = new_body.replace(new, old);
1372 result += new_body.trim();
1373 } else if !new_body.is_empty() {
1375 result += &new_body;
1376 result += &shape.indent.to_string(&config);
1385 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1387 /// # Expected syntax
1391 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1392 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1394 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1397 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1398 let mut result = String::with_capacity(1024);
1399 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1400 let nested_shape = shape
1401 .block_indent(context.config.tab_spaces())
1402 .with_max_width(context.config);
1404 result.push_str("lazy_static! {");
1405 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1407 macro_rules! parse_or {
1408 ($method:ident $(,)* $($arg:expr),* $(,)*) => {
1409 match parser.$method($($arg,)*) {
1411 if parser.sess.span_diagnostic.has_errors() {
1412 parser.sess.span_diagnostic.reset_err_count();
1420 parser.sess.span_diagnostic.reset_err_count();
1427 while parser.token != Token::Eof {
1428 // Parse a `lazy_static!` item.
1429 let vis = ::utils::format_visibility(context, &parse_or!(parse_visibility, false));
1430 parser.eat_keyword(symbol::keywords::Static);
1431 parser.eat_keyword(symbol::keywords::Ref);
1432 let id = parse_or!(parse_ident);
1433 parser.eat(&Token::Colon);
1434 let ty = parse_or!(parse_ty);
1435 parser.eat(&Token::Eq);
1436 let expr = parse_or!(parse_expr);
1437 parser.eat(&Token::Semi);
1439 // Rewrite as a static item.
1440 let mut stmt = String::with_capacity(128);
1441 stmt.push_str(&format!(
1442 "{}static ref {}: {} =",
1445 ty.rewrite(context, nested_shape)?
1447 result.push_str(&::expr::rewrite_assign_rhs(
1451 nested_shape.sub_width(1)?,
1454 if parser.token != Token::Eof {
1455 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1459 result.push_str(&shape.indent.to_string_with_newline(context.config));
1465 fn rewrite_macro_with_items(
1466 context: &RewriteContext,
1471 position: MacroPosition,
1473 ) -> Option<String> {
1474 let (opener, closer) = match style {
1475 DelimToken::Paren => ("(", ")"),
1476 DelimToken::Bracket => ("[", "]"),
1477 DelimToken::Brace => (" {", "}"),
1480 let trailing_semicolon = match style {
1481 DelimToken::Paren | DelimToken::Bracket if position == MacroPosition::Item => ";",
1485 let mut visitor = FmtVisitor::from_context(context);
1486 visitor.block_indent = shape.indent.block_indent(context.config);
1487 visitor.last_pos = context.snippet_provider.span_after(span, opener.trim());
1489 let item = match item {
1490 MacroArg::Item(item) => item,
1493 visitor.visit_item(&item);
1496 let mut result = String::with_capacity(256);
1497 result.push_str(¯o_name);
1498 result.push_str(opener);
1499 result.push_str(&visitor.block_indent.to_string_with_newline(context.config));
1500 result.push_str(visitor.buffer.trim());
1501 result.push_str(&shape.indent.to_string_with_newline(context.config));
1502 result.push_str(closer);
1503 result.push_str(trailing_semicolon);