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 // Use this on failing to format the macro call.
133 fn return_original_snippet_with_failure_marked(
134 context: &RewriteContext,
136 ) -> Option<String> {
137 context.macro_rewrite_failure.replace(true);
138 Some(context.snippet(span).to_owned())
141 pub fn rewrite_macro(
143 extra_ident: Option<ast::Ident>,
144 context: &RewriteContext,
146 position: MacroPosition,
147 ) -> Option<String> {
148 context.inside_macro.replace(true);
149 let result = rewrite_macro_inner(mac, extra_ident, context, shape, position);
150 if result.is_none() {
151 context.macro_rewrite_failure.replace(true);
153 context.inside_macro.replace(false);
157 pub fn rewrite_macro_inner(
159 extra_ident: Option<ast::Ident>,
160 context: &RewriteContext,
162 position: MacroPosition,
163 ) -> Option<String> {
164 if context.config.use_try_shorthand() {
165 if let Some(expr) = convert_try_mac(mac, context) {
166 context.inside_macro.replace(false);
167 return expr.rewrite(context, shape);
171 let original_style = macro_style(mac, context);
173 let macro_name = rewrite_macro_name(&mac.node.path, extra_ident);
175 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
181 let ts: TokenStream = mac.node.stream();
182 let has_comment = contains_comment(context.snippet(mac.span));
183 if ts.is_empty() && !has_comment {
185 DelimToken::Paren if position == MacroPosition::Item => {
186 Some(format!("{}();", macro_name))
188 DelimToken::Paren => Some(format!("{}()", macro_name)),
189 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
190 DelimToken::Brace => Some(format!("{}{{}}", macro_name)),
194 // Format well-known macros which cannot be parsed as a valid AST.
195 // TODO: Maybe add more macros?
196 if macro_name == "lazy_static!" && !has_comment {
197 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
202 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
203 let mut arg_vec = Vec::new();
204 let mut vec_with_semi = false;
205 let mut trailing_comma = false;
207 if DelimToken::Brace != style {
209 match parse_macro_arg(&mut parser) {
210 Some(arg) => arg_vec.push(arg),
211 None => return return_original_snippet_with_failure_marked(context, mac.span),
218 // Try to parse `vec![expr; expr]`
219 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
221 if parser.token != Token::Eof {
222 match parse_macro_arg(&mut parser) {
226 if parser.token == Token::Eof && arg_vec.len() == 2 {
227 vec_with_semi = true;
232 return return_original_snippet_with_failure_marked(
239 return return_original_snippet_with_failure_marked(context, mac.span);
241 _ => return return_original_snippet_with_failure_marked(context, mac.span),
246 if parser.token == Token::Eof {
247 trailing_comma = true;
254 DelimToken::Paren => {
255 // Format macro invocation as function call, preserve the trailing
256 // comma because not all macros support them.
257 overflow::rewrite_with_parens(
260 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>(),
263 context.config.width_heuristics().fn_call_width,
265 Some(SeparatorTactic::Always)
267 Some(SeparatorTactic::Never)
269 ).map(|rw| match position {
270 MacroPosition::Item => format!("{};", rw),
274 DelimToken::Bracket => {
275 // Handle special case: `vec![expr; expr]`
277 let mac_shape = shape.offset_left(macro_name.len())?;
278 // 8 = `vec![]` + `; `
279 let total_overhead = 8;
280 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
281 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
282 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
283 if !lhs.contains('\n')
284 && !rhs.contains('\n')
285 && lhs.len() + rhs.len() + total_overhead <= shape.width
287 Some(format!("{}[{}; {}]", macro_name, lhs, rhs))
292 nested_shape.indent.to_string_with_newline(context.config),
294 nested_shape.indent.to_string_with_newline(context.config),
296 shape.indent.to_string_with_newline(context.config),
300 // If we are rewriting `vec!` macro or other special macros,
301 // then we can rewrite this as an usual array literal.
302 // Otherwise, we must preserve the original existence of trailing comma.
303 let macro_name = ¯o_name.as_str();
304 let mut force_trailing_comma = if trailing_comma {
305 Some(SeparatorTactic::Always)
307 Some(SeparatorTactic::Never)
309 if FORCED_BRACKET_MACROS.contains(macro_name) {
310 context.inside_macro.replace(false);
311 if context.use_block_indent() {
312 force_trailing_comma = Some(SeparatorTactic::Vertical);
315 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
316 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>();
317 let rewrite = rewrite_array(
323 force_trailing_comma,
324 Some(original_style),
326 let comma = match position {
327 MacroPosition::Item => ";",
331 Some(format!("{}{}", rewrite, comma))
334 DelimToken::Brace => {
335 // Skip macro invocations with braces, for now.
336 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
342 pub fn rewrite_macro_def(
343 context: &RewriteContext,
348 vis: &ast::Visibility,
350 ) -> Option<String> {
351 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
352 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
356 let mut parser = MacroParser::new(def.stream().into_trees());
357 let parsed_def = match parser.parse() {
359 None => return snippet,
362 let mut result = if def.legacy {
363 String::from("macro_rules!")
365 format!("{}macro", format_visibility(vis))
369 result += &ident.name.as_str();
371 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
373 let arm_shape = if multi_branch_style {
375 .block_indent(context.config.tab_spaces())
376 .with_max_width(context.config)
381 let branch_items = itemize_list(
382 context.snippet_provider,
383 parsed_def.branches.iter(),
386 |branch| branch.span.lo(),
387 |branch| branch.span.hi(),
388 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
389 context.snippet_provider.span_after(span, "{"),
392 ).collect::<Vec<_>>();
394 let fmt = ListFormatting {
395 tactic: DefinitiveListTactic::Vertical,
396 separator: if def.legacy { ";" } else { "" },
397 trailing_separator: SeparatorTactic::Always,
398 separator_place: SeparatorPlace::Back,
400 ends_with_newline: true,
401 preserve_newline: true,
403 config: context.config,
406 if multi_branch_style {
408 result += &arm_shape.indent.to_string_with_newline(context.config);
411 result += write_list(&branch_items, &fmt)?.as_str();
413 if multi_branch_style {
414 result += &indent.to_string_with_newline(context.config);
421 fn register_metavariable(
422 map: &mut HashMap<String, String>,
427 let mut new_name = String::new();
428 let mut old_name = String::new();
431 for _ in 0..(dollar_count - 1) {
436 new_name.push_str(&name);
437 old_name.push_str(&name);
439 result.push_str(&new_name);
440 map.insert(old_name, new_name);
443 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
444 // aren't causing problems.
445 // This should also work for escaped `$` variables, where we leave earlier `$`s.
446 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
447 // Each substitution will require five or six extra bytes.
448 let mut result = String::with_capacity(input.len() + 64);
449 let mut substs = HashMap::new();
450 let mut dollar_count = 0;
451 let mut cur_name = String::new();
453 for (kind, c) in CharClasses::new(input.chars()) {
454 if kind != FullCodeCharKind::Normal {
458 } else if dollar_count == 0 {
460 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
461 // Terminates a name following one or more dollars.
462 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
467 } else if c == '(' && cur_name.is_empty() {
468 // FIXME: Support macro def with repeat.
470 } else if c.is_alphanumeric() || c == '_' {
475 if !cur_name.is_empty() {
476 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
479 debug!("replace_names `{}` {:?}", result, substs);
481 Some((result, substs))
484 #[derive(Debug, Clone)]
487 MetaVariable(ast::Ident, String),
488 /// e.g. `$($foo: expr),*`
490 /// `()`, `[]` or `{}`.
492 /// Inner arguments inside delimiters.
494 /// Something after the closing delimiter and the repeat token, if available.
495 Option<Box<ParsedMacroArg>>,
496 /// The repeat token. This could be one of `*`, `+` or `?`.
499 /// e.g. `[derive(Debug)]`
500 Delimited(DelimToken, Vec<ParsedMacroArg>),
501 /// A possible separator. e.g. `,` or `;`.
502 Separator(String, String),
503 /// Other random stuff that does not fit to other kinds.
504 /// e.g. `== foo` in `($x: expr == foo)`.
505 Other(String, String),
508 fn delim_token_to_str(
509 context: &RewriteContext,
510 delim_token: &DelimToken,
512 use_multiple_lines: bool,
513 inner_is_empty: bool,
514 ) -> (String, String) {
515 let (lhs, rhs) = match *delim_token {
516 DelimToken::Paren => ("(", ")"),
517 DelimToken::Bracket => ("[", "]"),
518 DelimToken::Brace => {
519 if inner_is_empty || use_multiple_lines {
525 DelimToken::NoDelim => ("", ""),
527 if use_multiple_lines {
528 let indent_str = shape.indent.to_string_with_newline(context.config);
529 let nested_indent_str = shape
531 .block_indent(context.config)
532 .to_string_with_newline(context.config);
534 format!("{}{}", lhs, nested_indent_str),
535 format!("{}{}", indent_str, rhs),
538 (lhs.to_owned(), rhs.to_owned())
543 fn starts_with_brace(&self) -> bool {
545 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
546 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
551 fn starts_with_dollar(&self) -> bool {
553 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
558 fn ends_with_space(&self) -> bool {
560 MacroArgKind::Separator(..) => true,
565 fn has_meta_var(&self) -> bool {
567 MacroArgKind::MetaVariable(..) => true,
568 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
575 context: &RewriteContext,
577 use_multiple_lines: bool,
578 ) -> Option<String> {
579 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
580 let inner = wrap_macro_args(context, args, shape)?;
581 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
582 if lhs.len() + inner.len() + rhs.len() <= shape.width {
583 return Some((lhs, inner, rhs));
586 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
587 let nested_shape = shape
588 .block_indent(context.config.tab_spaces())
589 .with_max_width(context.config);
590 let inner = wrap_macro_args(context, args, nested_shape)?;
591 Some((lhs, inner, rhs))
595 MacroArgKind::MetaVariable(ty, ref name) => {
596 Some(format!("${}:{}", name, ty.name.as_str()))
598 MacroArgKind::Repeat(ref delim_tok, ref args, ref another, ref tok) => {
599 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
600 let another = another
602 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
603 .unwrap_or_else(|| "".to_owned());
604 let repeat_tok = pprust::token_to_string(tok);
606 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
608 MacroArgKind::Delimited(ref delim_tok, ref args) => {
609 rewrite_delimited_inner(delim_tok, args)
610 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
612 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
613 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
618 #[derive(Debug, Clone)]
619 struct ParsedMacroArg {
624 impl ParsedMacroArg {
627 context: &RewriteContext,
629 use_multiple_lines: bool,
630 ) -> Option<String> {
631 self.kind.rewrite(context, shape, use_multiple_lines)
635 /// Parses macro arguments on macro def.
636 struct MacroArgParser {
637 /// Holds either a name of the next metavariable, a separator or a junk.
639 /// The start position on the current buffer.
641 /// The first token of the current buffer.
643 /// Set to true if we are parsing a metavariable or a repeat.
645 /// The position of the last token.
647 /// The last token parsed.
649 /// Holds the parsed arguments.
650 result: Vec<ParsedMacroArg>,
653 fn last_tok(tt: &TokenTree) -> Token {
655 TokenTree::Token(_, ref t) => t.clone(),
656 TokenTree::Delimited(_, ref d) => d.close_token(),
660 impl MacroArgParser {
661 pub fn new() -> MacroArgParser {
667 last_tok: Token::Eof,
668 start_tok: Token::Eof,
673 fn set_last_tok(&mut self, tok: &TokenTree) {
674 self.hi = tok.span().hi();
675 self.last_tok = last_tok(tok);
678 fn add_separator(&mut self) {
679 let prefix = if self.need_space_prefix() {
684 self.result.push(ParsedMacroArg {
685 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
686 span: mk_sp(self.lo, self.hi),
691 fn add_other(&mut self) {
692 let prefix = if self.need_space_prefix() {
697 self.result.push(ParsedMacroArg {
698 kind: MacroArgKind::Other(self.buf.clone(), prefix),
699 span: mk_sp(self.lo, self.hi),
704 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
706 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
707 self.result.push(ParsedMacroArg {
708 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
709 span: mk_sp(self.lo, sp.hi()),
713 self.is_meta_var = false;
720 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
721 self.result.push(ParsedMacroArg {
722 kind: MacroArgKind::Delimited(delim, inner),
730 inner: Vec<ParsedMacroArg>,
735 let mut buffer = String::new();
736 let mut first = false;
737 let mut lo = span.lo();
738 let mut hi = span.hi();
740 // Parse '*', '+' or '?.
741 for ref tok in iter {
742 self.set_last_tok(tok);
745 lo = tok.span().lo();
749 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
750 | TokenTree::Token(_, Token::Question)
751 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
754 TokenTree::Token(sp, ref t) => {
755 buffer.push_str(&pprust::token_to_string(t));
762 // There could be some random stuff between ')' and '*', '+' or '?'.
763 let another = if buffer.trim().is_empty() {
766 Some(Box::new(ParsedMacroArg {
767 kind: MacroArgKind::Other(buffer, "".to_owned()),
772 self.result.push(ParsedMacroArg {
773 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
774 span: mk_sp(self.lo, self.hi),
779 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
780 if self.buf.is_empty() {
782 self.start_tok = t.clone();
784 let needs_space = match next_space(&self.last_tok) {
785 SpaceState::Ident => ident_like(t),
786 SpaceState::Punctuation => !ident_like(t),
787 SpaceState::Always => true,
788 SpaceState::Never => false,
790 if force_space_before(t) || needs_space {
795 self.buf.push_str(&pprust::token_to_string(t));
798 fn need_space_prefix(&self) -> bool {
799 if self.result.is_empty() {
803 let last_arg = self.result.last().unwrap();
804 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
805 if ident_like(&self.start_tok) {
808 if self.start_tok == Token::Colon {
813 if force_space_before(&self.start_tok) {
820 /// Returns a collection of parsed macro def's arguments.
821 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
822 let mut iter = (tokens.into(): TokenStream).trees();
824 while let Some(ref tok) = iter.next() {
826 TokenTree::Token(sp, Token::Dollar) => {
827 // We always want to add a separator before meta variables.
828 if !self.buf.is_empty() {
829 self.add_separator();
832 // Start keeping the name of this metavariable in the buffer.
833 self.is_meta_var = true;
835 self.start_tok = Token::Dollar;
837 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
838 self.add_meta_variable(&mut iter)?;
840 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
841 TokenTree::Delimited(sp, delimited) => {
842 if !self.buf.is_empty() {
843 if next_space(&self.last_tok) == SpaceState::Always {
844 self.add_separator();
850 // Parse the stuff inside delimiters.
851 let mut parser = MacroArgParser::new();
853 let delimited_arg = parser.parse(delimited.tts.clone())?;
855 if self.is_meta_var {
856 self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp)?;
857 self.is_meta_var = false;
859 self.add_delimited(delimited_arg, delimited.delim, *sp);
864 self.set_last_tok(tok);
867 // We are left with some stuff in the buffer. Since there is nothing
868 // left to separate, add this as `Other`.
869 if !self.buf.is_empty() {
878 context: &RewriteContext,
879 args: &[ParsedMacroArg],
881 ) -> Option<String> {
882 wrap_macro_args_inner(context, args, shape, false)
883 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
886 fn wrap_macro_args_inner(
887 context: &RewriteContext,
888 args: &[ParsedMacroArg],
890 use_multiple_lines: bool,
891 ) -> Option<String> {
892 let mut result = String::with_capacity(128);
893 let mut iter = args.iter().peekable();
894 let indent_str = shape.indent.to_string_with_newline(context.config);
896 while let Some(ref arg) = iter.next() {
897 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
899 if use_multiple_lines
900 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
902 if arg.kind.ends_with_space() {
905 result.push_str(&indent_str);
906 } else if let Some(ref next_arg) = iter.peek() {
907 let space_before_dollar =
908 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
909 let space_before_brace = next_arg.kind.starts_with_brace();
910 if space_before_dollar || space_before_brace {
916 if !use_multiple_lines && result.len() >= shape.width {
923 // This is a bit sketchy. The token rules probably need tweaking, but it works
924 // for some common cases. I hope the basic logic is sufficient. Note that the
925 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
926 // and `(`/`)` have special meaning.
928 // We always try and format on one line.
929 // FIXME: Use multi-line when every thing does not fit on one line.
930 fn format_macro_args(
931 context: &RewriteContext,
932 toks: ThinTokenStream,
934 ) -> Option<String> {
935 let parsed_args = MacroArgParser::new().parse(toks)?;
936 wrap_macro_args(context, &parsed_args, shape)
939 // We should insert a space if the next token is a:
940 #[derive(Copy, Clone, PartialEq)]
944 Ident, // Or ident/literal-like thing.
948 fn force_space_before(tok: &Token) -> bool {
949 debug!("tok: force_space_before {:?}", tok);
970 | Token::Dollar => true,
975 fn ident_like(tok: &Token) -> bool {
977 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
982 fn next_space(tok: &Token) -> SpaceState {
983 debug!("next_space: {:?}", tok);
987 | Token::BinOp(BinOpToken::And)
996 | Token::Question => SpaceState::Punctuation,
1001 | Token::OpenDelim(_)
1002 | Token::CloseDelim(_)
1003 | Token::Whitespace => SpaceState::Never,
1005 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
1007 _ => SpaceState::Always,
1011 /// Tries to convert a macro use into a short hand try expression. Returns None
1012 /// when the macro is not an instance of try! (or parsing the inner expression
1014 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
1015 if &format!("{}", mac.node.path) == "try" {
1016 let ts: TokenStream = mac.node.tts.clone().into();
1017 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1020 id: ast::NodeId::new(0), // dummy value
1021 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1022 span: mac.span, // incorrect span, but shouldn't matter too much
1023 attrs: ThinVec::new(),
1030 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1031 let snippet = context.snippet(mac.span);
1032 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1033 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1034 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1036 if paren_pos < bracket_pos && paren_pos < brace_pos {
1038 } else if bracket_pos < brace_pos {
1045 /// Indent each line according to the specified `indent`.
1073 fn indent_macro_snippet(
1074 context: &RewriteContext,
1077 ) -> Option<String> {
1078 let mut lines = LineClasses::new(macro_str);
1079 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1080 let mut trimmed_lines = Vec::with_capacity(16);
1082 let mut veto_trim = false;
1083 let min_prefix_space_width = lines
1084 .filter_map(|(kind, line)| {
1085 let mut trimmed = true;
1086 let prefix_space_width = if is_empty_line(&line) {
1089 Some(get_prefix_space_width(context, &line))
1091 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1092 veto_trim = kind.is_string() && !line.ends_with('\\');
1096 line.trim().to_owned()
1098 trimmed_lines.push((trimmed, line, prefix_space_width));
1108 |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
1109 _ if !trimmed => line.to_owned(),
1110 Some(original_indent_width) => {
1111 let new_indent_width = indent.width()
1112 + original_indent_width.saturating_sub(min_prefix_space_width);
1113 let new_indent = Indent::from_width(context.config, new_indent_width);
1114 format!("{}{}", new_indent.to_string(context.config), line.trim())
1116 None => String::new(),
1119 .collect::<Vec<_>>()
1124 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1126 for c in s.chars() {
1129 '\t' => width += context.config.tab_spaces(),
1136 fn is_empty_line(s: &str) -> bool {
1137 s.is_empty() || s.chars().all(char::is_whitespace)
1140 // A very simple parser that just parses a macros 2.0 definition into its branches.
1141 // Currently we do not attempt to parse any further than that.
1143 struct MacroParser {
1148 // (`(` ... `)` `=>` `{` ... `}`)*
1149 fn parse(&mut self) -> Option<Macro> {
1150 let mut branches = vec![];
1151 while self.toks.look_ahead(1).is_some() {
1152 branches.push(self.parse_branch()?);
1155 Some(Macro { branches })
1158 // `(` ... `)` `=>` `{` ... `}`
1159 fn parse_branch(&mut self) -> Option<MacroBranch> {
1160 let tok = self.toks.next()?;
1161 let (lo, args_paren_kind) = match tok {
1162 TokenTree::Token(..) => return None,
1163 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
1165 let args = tok.joint().into();
1166 match self.toks.next()? {
1167 TokenTree::Token(_, Token::FatArrow) => {}
1170 let (mut hi, body) = match self.toks.next()? {
1171 TokenTree::Token(..) => return None,
1172 TokenTree::Delimited(sp, _) => {
1173 let data = sp.data();
1176 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1180 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1185 span: mk_sp(lo, hi),
1193 // A parsed macros 2.0 macro definition.
1195 branches: Vec<MacroBranch>,
1198 // FIXME: it would be more efficient to use references to the token streams
1199 // rather than clone them, if we can make the borrowing work out.
1200 struct MacroBranch {
1202 args_paren_kind: DelimToken,
1203 args: ThinTokenStream,
1210 context: &RewriteContext,
1212 multi_branch_style: bool,
1213 ) -> Option<String> {
1214 // Only attempt to format function-like macros.
1215 if self.args_paren_kind != DelimToken::Paren {
1216 // FIXME(#1539): implement for non-sugared macros.
1221 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1223 if multi_branch_style {
1227 // The macro body is the most interesting part. It might end up as various
1228 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1229 // parsed as regular Rust code (and note that these can be escaped using
1230 // `$$`). We'll try and format like an AST node, but we'll substitute
1231 // variables for new names with the same length first.
1233 let old_body = context.snippet(self.body).trim();
1234 let (body_str, substs) = replace_names(old_body)?;
1236 let mut config = context.config.clone();
1237 config.set().hide_parse_errors(true);
1241 let has_block_body = old_body.starts_with('{');
1243 let body_indent = if has_block_body {
1246 // We'll hack the indent below, take this into account when formatting,
1247 let body_indent = shape.indent.block_indent(&config);
1248 let new_width = config.max_width() - body_indent.width();
1249 config.set().max_width(new_width);
1253 // First try to format as items, then as statements.
1254 let new_body = match ::format_snippet(&body_str, &config) {
1255 Some(new_body) => new_body,
1256 None => match ::format_code_block(&body_str, &config) {
1257 Some(new_body) => new_body,
1258 None => return None,
1261 let new_body = wrap_str(new_body, config.max_width(), shape)?;
1263 // Indent the body since it is in a block.
1264 let indent_str = body_indent.to_string(&config);
1265 let mut new_body = LineClasses::new(new_body.trim_right())
1267 (String::new(), true),
1268 |(mut s, need_indent), (kind, ref l)| {
1269 if !l.is_empty() && need_indent {
1272 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1277 // Undo our replacement of macro variables.
1278 // FIXME: this could be *much* more efficient.
1279 for (old, new) in &substs {
1280 if old_body.find(new).is_some() {
1281 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1284 new_body = new_body.replace(new, old);
1288 result += new_body.trim();
1289 } else if !new_body.is_empty() {
1291 result += &new_body;
1292 result += &shape.indent.to_string(&config);
1301 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1303 /// # Expected syntax
1307 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1308 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1310 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1313 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1314 let mut result = String::with_capacity(1024);
1315 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1316 let nested_shape = shape
1317 .block_indent(context.config.tab_spaces())
1318 .with_max_width(context.config);
1320 result.push_str("lazy_static! {");
1321 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1323 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1324 match parser.$method($($arg,)*) {
1326 if parser.sess.span_diagnostic.has_errors() {
1327 parser.sess.span_diagnostic.reset_err_count();
1335 parser.sess.span_diagnostic.reset_err_count();
1341 while parser.token != Token::Eof {
1342 // Parse a `lazy_static!` item.
1343 let vis = ::utils::format_visibility(&parse_or!(parse_visibility, false));
1344 parser.eat_keyword(symbol::keywords::Static);
1345 parser.eat_keyword(symbol::keywords::Ref);
1346 let id = parse_or!(parse_ident);
1347 parser.eat(&Token::Colon);
1348 let ty = parse_or!(parse_ty);
1349 parser.eat(&Token::Eq);
1350 let expr = parse_or!(parse_expr);
1351 parser.eat(&Token::Semi);
1353 // Rewrite as a static item.
1354 let mut stmt = String::with_capacity(128);
1355 stmt.push_str(&format!(
1356 "{}static ref {}: {} =",
1359 ty.rewrite(context, nested_shape)?
1361 result.push_str(&::expr::rewrite_assign_rhs(
1365 nested_shape.sub_width(1)?,
1368 if parser.token != Token::Eof {
1369 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1373 result.push_str(&shape.indent.to_string_with_newline(context.config));