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};
36 contains_comment, remove_trailing_white_spaces, CharClasses, FindUncommented, FullCodeCharKind,
39 use expr::rewrite_array;
40 use lists::{itemize_list, write_list, ListFormatting};
42 use rewrite::{Rewrite, RewriteContext};
43 use shape::{Indent, Shape};
44 use source_map::SpanUtils;
46 use utils::{format_visibility, mk_sp, rewrite_ident, wrap_str};
47 use visitor::FmtVisitor;
49 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
51 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
52 pub enum MacroPosition {
61 Expr(ptr::P<ast::Expr>),
63 Pat(ptr::P<ast::Pat>),
64 Item(ptr::P<ast::Item>),
68 fn is_item(&self) -> bool {
70 MacroArg::Item(..) => true,
76 impl Rewrite for ast::Item {
77 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
78 let mut visitor = ::visitor::FmtVisitor::from_context(context);
79 visitor.block_indent = shape.indent;
80 visitor.last_pos = self.span().lo();
81 visitor.visit_item(self);
82 Some(visitor.buffer.to_owned())
86 impl Rewrite for MacroArg {
87 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
89 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
90 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
91 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
92 MacroArg::Item(ref item) => item.rewrite(context, shape),
97 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
98 macro_rules! parse_macro_arg {
99 ($macro_arg:ident, $parser:ident, $f:expr) => {
100 let mut cloned_parser = (*parser).clone();
101 match cloned_parser.$parser() {
103 if parser.sess.span_diagnostic.has_errors() {
104 parser.sess.span_diagnostic.reset_err_count();
106 // Parsing succeeded.
107 *parser = cloned_parser;
108 return Some(MacroArg::$macro_arg($f(x)?));
113 parser.sess.span_diagnostic.reset_err_count();
119 parse_macro_arg!(Expr, parse_expr, |x: ptr::P<ast::Expr>| Some(x));
120 parse_macro_arg!(Ty, parse_ty, |x: ptr::P<ast::Ty>| Some(x));
121 parse_macro_arg!(Pat, parse_pat, |x: ptr::P<ast::Pat>| Some(x));
122 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
123 parse_macro_arg!(Item, parse_item, |x: Option<ptr::P<ast::Item>>| x);
128 /// Rewrite macro name without using pretty-printer if possible.
129 fn rewrite_macro_name(
130 context: &RewriteContext,
132 extra_ident: Option<ast::Ident>,
134 let name = if path.segments.len() == 1 {
135 // Avoid using pretty-printer in the common case.
136 format!("{}!", rewrite_ident(context, path.segments[0].ident))
141 Some(ident) if ident != symbol::keywords::Invalid.ident() => format!("{} {}", name, ident),
146 // Use this on failing to format the macro call.
147 fn return_original_snippet_with_failure_marked(
148 context: &RewriteContext,
150 ) -> Option<String> {
151 context.macro_rewrite_failure.replace(true);
152 Some(context.snippet(span).to_owned())
155 struct InsideMacroGuard<'a> {
156 context: &'a RewriteContext<'a>,
160 impl<'a> InsideMacroGuard<'a> {
161 fn inside_macro_context(context: &'a RewriteContext) -> InsideMacroGuard<'a> {
162 let is_nested = context.inside_macro.replace(true);
163 InsideMacroGuard { context, is_nested }
167 impl<'a> Drop for InsideMacroGuard<'a> {
169 self.context.inside_macro.replace(self.is_nested);
173 pub fn rewrite_macro(
175 extra_ident: Option<ast::Ident>,
176 context: &RewriteContext,
178 position: MacroPosition,
179 ) -> Option<String> {
180 let guard = InsideMacroGuard::inside_macro_context(context);
181 let result = rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
182 if result.is_none() {
183 context.macro_rewrite_failure.replace(true);
188 pub fn rewrite_macro_inner(
190 extra_ident: Option<ast::Ident>,
191 context: &RewriteContext,
193 position: MacroPosition,
194 is_nested_macro: bool,
195 ) -> Option<String> {
196 if context.config.use_try_shorthand() {
197 if let Some(expr) = convert_try_mac(mac, context) {
198 context.inside_macro.replace(false);
199 return expr.rewrite(context, shape);
203 let original_style = macro_style(mac, context);
205 let macro_name = rewrite_macro_name(context, &mac.node.path, extra_ident);
207 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) && !is_nested_macro {
213 let ts: TokenStream = mac.node.stream();
214 let has_comment = contains_comment(context.snippet(mac.span));
215 if ts.is_empty() && !has_comment {
217 DelimToken::Paren if position == MacroPosition::Item => {
218 Some(format!("{}();", macro_name))
220 DelimToken::Paren => Some(format!("{}()", macro_name)),
221 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
222 DelimToken::Brace => Some(format!("{}{{}}", macro_name)),
226 // Format well-known macros which cannot be parsed as a valid AST.
227 if macro_name == "lazy_static!" && !has_comment {
228 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
233 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
234 let mut arg_vec = Vec::new();
235 let mut vec_with_semi = false;
236 let mut trailing_comma = false;
238 if DelimToken::Brace != style {
240 match parse_macro_arg(&mut parser) {
241 Some(arg) => arg_vec.push(arg),
242 None => return return_original_snippet_with_failure_marked(context, mac.span),
249 // Try to parse `vec![expr; expr]`
250 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
252 if parser.token != Token::Eof {
253 match parse_macro_arg(&mut parser) {
257 if parser.token == Token::Eof && arg_vec.len() == 2 {
258 vec_with_semi = true;
263 return return_original_snippet_with_failure_marked(
270 return return_original_snippet_with_failure_marked(context, mac.span);
272 _ if arg_vec.last().map_or(false, MacroArg::is_item) => continue,
273 _ => return return_original_snippet_with_failure_marked(context, mac.span),
278 if parser.token == Token::Eof {
279 trailing_comma = true;
285 if !arg_vec.is_empty() && arg_vec.iter().all(MacroArg::is_item) {
286 return rewrite_macro_with_items(
298 DelimToken::Paren => {
299 // Format macro invocation as function call, preserve the trailing
300 // comma because not all macros support them.
301 overflow::rewrite_with_parens(
307 context.config.width_heuristics().fn_call_width,
309 Some(SeparatorTactic::Always)
311 Some(SeparatorTactic::Never)
314 .map(|rw| match position {
315 MacroPosition::Item => format!("{};", rw),
319 DelimToken::Bracket => {
320 // Handle special case: `vec![expr; expr]`
322 let mac_shape = shape.offset_left(macro_name.len())?;
323 // 8 = `vec![]` + `; `
324 let total_overhead = 8;
325 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
326 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
327 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
328 if !lhs.contains('\n')
329 && !rhs.contains('\n')
330 && lhs.len() + rhs.len() + total_overhead <= shape.width
332 Some(format!("{}[{}; {}]", macro_name, lhs, rhs))
337 nested_shape.indent.to_string_with_newline(context.config),
339 nested_shape.indent.to_string_with_newline(context.config),
341 shape.indent.to_string_with_newline(context.config),
345 // If we are rewriting `vec!` macro or other special macros,
346 // then we can rewrite this as an usual array literal.
347 // Otherwise, we must preserve the original existence of trailing comma.
348 let macro_name = ¯o_name.as_str();
349 let mut force_trailing_comma = if trailing_comma {
350 Some(SeparatorTactic::Always)
352 Some(SeparatorTactic::Never)
354 if FORCED_BRACKET_MACROS.contains(macro_name) && !is_nested_macro {
355 context.inside_macro.replace(false);
356 if context.use_block_indent() {
357 force_trailing_comma = Some(SeparatorTactic::Vertical);
360 let rewrite = rewrite_array(
366 force_trailing_comma,
367 Some(original_style),
369 let comma = match position {
370 MacroPosition::Item => ";",
374 Some(format!("{}{}", rewrite, comma))
377 DelimToken::Brace => {
378 // Skip macro invocations with braces, for now.
379 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
385 pub fn rewrite_macro_def(
386 context: &RewriteContext,
391 vis: &ast::Visibility,
393 ) -> Option<String> {
394 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
395 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
399 let mut parser = MacroParser::new(def.stream().into_trees());
400 let parsed_def = match parser.parse() {
402 None => return snippet,
405 let mut result = if def.legacy {
406 String::from("macro_rules!")
408 format!("{}macro", format_visibility(context, vis))
412 result += rewrite_ident(context, ident);
414 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
416 let arm_shape = if multi_branch_style {
418 .block_indent(context.config.tab_spaces())
419 .with_max_width(context.config)
424 let branch_items = itemize_list(
425 context.snippet_provider,
426 parsed_def.branches.iter(),
429 |branch| branch.span.lo(),
430 |branch| branch.span.hi(),
431 |branch| match branch.rewrite(context, arm_shape, multi_branch_style) {
433 // if the rewrite returned None because a macro could not be rewritten, then return the
435 None if *context.macro_rewrite_failure.borrow() == true => {
436 Some(context.snippet(branch.body).trim().to_string())
440 context.snippet_provider.span_after(span, "{"),
444 .collect::<Vec<_>>();
446 let fmt = ListFormatting::new(arm_shape, context.config)
447 .separator(if def.legacy { ";" } else { "" })
448 .trailing_separator(SeparatorTactic::Always)
449 .preserve_newline(true);
451 if multi_branch_style {
453 result += &arm_shape.indent.to_string_with_newline(context.config);
456 match write_list(&branch_items, &fmt) {
457 Some(ref s) => result += s,
458 None => return snippet,
461 if multi_branch_style {
462 result += &indent.to_string_with_newline(context.config);
469 fn register_metavariable(
470 map: &mut HashMap<String, String>,
475 let mut new_name = String::new();
476 let mut old_name = String::new();
479 for _ in 0..(dollar_count - 1) {
484 new_name.push_str(&name);
485 old_name.push_str(&name);
487 result.push_str(&new_name);
488 map.insert(old_name, new_name);
491 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
492 // aren't causing problems.
493 // This should also work for escaped `$` variables, where we leave earlier `$`s.
494 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
495 // Each substitution will require five or six extra bytes.
496 let mut result = String::with_capacity(input.len() + 64);
497 let mut substs = HashMap::new();
498 let mut dollar_count = 0;
499 let mut cur_name = String::new();
501 for (kind, c) in CharClasses::new(input.chars()) {
502 if kind != FullCodeCharKind::Normal {
506 } else if dollar_count == 0 {
508 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
509 // Terminates a name following one or more dollars.
510 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
515 } else if c == '(' && cur_name.is_empty() {
516 // FIXME: Support macro def with repeat.
518 } else if c.is_alphanumeric() || c == '_' {
523 if !cur_name.is_empty() {
524 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
527 debug!("replace_names `{}` {:?}", result, substs);
529 Some((result, substs))
532 #[derive(Debug, Clone)]
535 MetaVariable(ast::Ident, String),
536 /// e.g. `$($foo: expr),*`
538 /// `()`, `[]` or `{}`.
540 /// Inner arguments inside delimiters.
542 /// Something after the closing delimiter and the repeat token, if available.
543 Option<Box<ParsedMacroArg>>,
544 /// The repeat token. This could be one of `*`, `+` or `?`.
547 /// e.g. `[derive(Debug)]`
548 Delimited(DelimToken, Vec<ParsedMacroArg>),
549 /// A possible separator. e.g. `,` or `;`.
550 Separator(String, String),
551 /// Other random stuff that does not fit to other kinds.
552 /// e.g. `== foo` in `($x: expr == foo)`.
553 Other(String, String),
556 fn delim_token_to_str(
557 context: &RewriteContext,
558 delim_token: DelimToken,
560 use_multiple_lines: bool,
561 inner_is_empty: bool,
562 ) -> (String, String) {
563 let (lhs, rhs) = match delim_token {
564 DelimToken::Paren => ("(", ")"),
565 DelimToken::Bracket => ("[", "]"),
566 DelimToken::Brace => {
567 if inner_is_empty || use_multiple_lines {
573 DelimToken::NoDelim => ("", ""),
575 if use_multiple_lines {
576 let indent_str = shape.indent.to_string_with_newline(context.config);
577 let nested_indent_str = shape
579 .block_indent(context.config)
580 .to_string_with_newline(context.config);
582 format!("{}{}", lhs, nested_indent_str),
583 format!("{}{}", indent_str, rhs),
586 (lhs.to_owned(), rhs.to_owned())
591 fn starts_with_brace(&self) -> bool {
593 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
594 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
599 fn starts_with_dollar(&self) -> bool {
601 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
606 fn ends_with_space(&self) -> bool {
608 MacroArgKind::Separator(..) => true,
613 fn has_meta_var(&self) -> bool {
615 MacroArgKind::MetaVariable(..) => true,
616 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
623 context: &RewriteContext,
625 use_multiple_lines: bool,
626 ) -> Option<String> {
627 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
628 let inner = wrap_macro_args(context, args, shape)?;
629 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false, inner.is_empty());
630 if lhs.len() + inner.len() + rhs.len() <= shape.width {
631 return Some((lhs, inner, rhs));
634 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true, false);
635 let nested_shape = shape
636 .block_indent(context.config.tab_spaces())
637 .with_max_width(context.config);
638 let inner = wrap_macro_args(context, args, nested_shape)?;
639 Some((lhs, inner, rhs))
643 MacroArgKind::MetaVariable(ty, ref name) => {
644 Some(format!("${}:{}", name, ty.name.as_str()))
646 MacroArgKind::Repeat(delim_tok, ref args, ref another, ref tok) => {
647 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
648 let another = another
650 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
651 .unwrap_or_else(|| "".to_owned());
652 let repeat_tok = pprust::token_to_string(tok);
654 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
656 MacroArgKind::Delimited(delim_tok, ref args) => {
657 rewrite_delimited_inner(delim_tok, args)
658 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
660 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
661 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
666 #[derive(Debug, Clone)]
667 struct ParsedMacroArg {
672 impl ParsedMacroArg {
675 context: &RewriteContext,
677 use_multiple_lines: bool,
678 ) -> Option<String> {
679 self.kind.rewrite(context, shape, use_multiple_lines)
683 /// Parses macro arguments on macro def.
684 struct MacroArgParser {
685 /// Holds either a name of the next metavariable, a separator or a junk.
687 /// The start position on the current buffer.
689 /// The first token of the current buffer.
691 /// Set to true if we are parsing a metavariable or a repeat.
693 /// The position of the last token.
695 /// The last token parsed.
697 /// Holds the parsed arguments.
698 result: Vec<ParsedMacroArg>,
701 fn last_tok(tt: &TokenTree) -> Token {
703 TokenTree::Token(_, ref t) => t.clone(),
704 TokenTree::Delimited(_, ref d) => d.close_token(),
708 impl MacroArgParser {
709 pub fn new() -> MacroArgParser {
715 last_tok: Token::Eof,
716 start_tok: Token::Eof,
721 fn set_last_tok(&mut self, tok: &TokenTree) {
722 self.hi = tok.span().hi();
723 self.last_tok = last_tok(tok);
726 fn add_separator(&mut self) {
727 let prefix = if self.need_space_prefix() {
732 self.result.push(ParsedMacroArg {
733 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
734 span: mk_sp(self.lo, self.hi),
739 fn add_other(&mut self) {
740 let prefix = if self.need_space_prefix() {
745 self.result.push(ParsedMacroArg {
746 kind: MacroArgKind::Other(self.buf.clone(), prefix),
747 span: mk_sp(self.lo, self.hi),
752 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
754 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
755 self.result.push(ParsedMacroArg {
756 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
757 span: mk_sp(self.lo, sp.hi()),
761 self.is_meta_var = false;
768 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
769 self.result.push(ParsedMacroArg {
770 kind: MacroArgKind::Delimited(delim, inner),
778 inner: Vec<ParsedMacroArg>,
783 let mut buffer = String::new();
784 let mut first = false;
785 let mut lo = span.lo();
786 let mut hi = span.hi();
788 // Parse '*', '+' or '?.
790 self.set_last_tok(&tok);
793 lo = tok.span().lo();
797 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
798 | TokenTree::Token(_, Token::Question)
799 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
802 TokenTree::Token(sp, ref t) => {
803 buffer.push_str(&pprust::token_to_string(t));
810 // There could be some random stuff between ')' and '*', '+' or '?'.
811 let another = if buffer.trim().is_empty() {
814 Some(Box::new(ParsedMacroArg {
815 kind: MacroArgKind::Other(buffer, "".to_owned()),
820 self.result.push(ParsedMacroArg {
821 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
822 span: mk_sp(self.lo, self.hi),
827 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
828 if self.buf.is_empty() {
830 self.start_tok = t.clone();
832 let needs_space = match next_space(&self.last_tok) {
833 SpaceState::Ident => ident_like(t),
834 SpaceState::Punctuation => !ident_like(t),
835 SpaceState::Always => true,
836 SpaceState::Never => false,
838 if force_space_before(t) || needs_space {
843 self.buf.push_str(&pprust::token_to_string(t));
846 fn need_space_prefix(&self) -> bool {
847 if self.result.is_empty() {
851 let last_arg = self.result.last().unwrap();
852 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
853 if ident_like(&self.start_tok) {
856 if self.start_tok == Token::Colon {
861 if force_space_before(&self.start_tok) {
868 /// Returns a collection of parsed macro def's arguments.
869 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
870 let mut iter = (tokens.into(): TokenStream).trees();
872 while let Some(ref tok) = iter.next() {
874 TokenTree::Token(sp, Token::Dollar) => {
875 // We always want to add a separator before meta variables.
876 if !self.buf.is_empty() {
877 self.add_separator();
880 // Start keeping the name of this metavariable in the buffer.
881 self.is_meta_var = true;
883 self.start_tok = Token::Dollar;
885 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
886 self.add_meta_variable(&mut iter)?;
888 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
889 TokenTree::Delimited(delimited_span, delimited) => {
890 if !self.buf.is_empty() {
891 if next_space(&self.last_tok) == SpaceState::Always {
892 self.add_separator();
898 // Parse the stuff inside delimiters.
899 let mut parser = MacroArgParser::new();
900 parser.lo = delimited_span.open.lo();
901 let delimited_arg = parser.parse(delimited.tts.clone())?;
903 let span = delimited_span.entire();
904 if self.is_meta_var {
905 self.add_repeat(delimited_arg, delimited.delim, &mut iter, span)?;
906 self.is_meta_var = false;
908 self.add_delimited(delimited_arg, delimited.delim, span);
913 self.set_last_tok(tok);
916 // We are left with some stuff in the buffer. Since there is nothing
917 // left to separate, add this as `Other`.
918 if !self.buf.is_empty() {
927 context: &RewriteContext,
928 args: &[ParsedMacroArg],
930 ) -> Option<String> {
931 wrap_macro_args_inner(context, args, shape, false)
932 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
935 fn wrap_macro_args_inner(
936 context: &RewriteContext,
937 args: &[ParsedMacroArg],
939 use_multiple_lines: bool,
940 ) -> Option<String> {
941 let mut result = String::with_capacity(128);
942 let mut iter = args.iter().peekable();
943 let indent_str = shape.indent.to_string_with_newline(context.config);
945 while let Some(ref arg) = iter.next() {
946 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
948 if use_multiple_lines
949 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
951 if arg.kind.ends_with_space() {
954 result.push_str(&indent_str);
955 } else if let Some(ref next_arg) = iter.peek() {
956 let space_before_dollar =
957 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
958 let space_before_brace = next_arg.kind.starts_with_brace();
959 if space_before_dollar || space_before_brace {
965 if !use_multiple_lines && result.len() >= shape.width {
972 // This is a bit sketchy. The token rules probably need tweaking, but it works
973 // for some common cases. I hope the basic logic is sufficient. Note that the
974 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
975 // and `(`/`)` have special meaning.
977 // We always try and format on one line.
978 // FIXME: Use multi-line when every thing does not fit on one line.
979 fn format_macro_args(
980 context: &RewriteContext,
981 toks: ThinTokenStream,
983 ) -> Option<String> {
984 if !context.config.format_macro_matchers() {
985 let token_stream: TokenStream = toks.into();
986 let span = span_for_token_stream(token_stream);
987 return Some(match span {
988 Some(span) => context.snippet(span).to_owned(),
989 None => String::new(),
992 let parsed_args = MacroArgParser::new().parse(toks)?;
993 wrap_macro_args(context, &parsed_args, shape)
996 fn span_for_token_stream(token_stream: TokenStream) -> Option<Span> {
997 token_stream.trees().next().map(|tt| tt.span())
1000 // We should insert a space if the next token is a:
1001 #[derive(Copy, Clone, PartialEq)]
1005 Ident, // Or ident/literal-like thing.
1009 fn force_space_before(tok: &Token) -> bool {
1010 debug!("tok: force_space_before {:?}", tok);
1031 | Token::Dollar => true,
1036 fn ident_like(tok: &Token) -> bool {
1038 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
1043 fn next_space(tok: &Token) -> SpaceState {
1044 debug!("next_space: {:?}", tok);
1048 | Token::BinOp(BinOpToken::And)
1057 | Token::Question => SpaceState::Punctuation,
1062 | Token::OpenDelim(_)
1063 | Token::CloseDelim(_)
1064 | Token::Whitespace => SpaceState::Never,
1066 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
1068 _ => SpaceState::Always,
1072 /// Tries to convert a macro use into a short hand try expression. Returns None
1073 /// when the macro is not an instance of try! (or parsing the inner expression
1075 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
1076 if &format!("{}", mac.node.path) == "try" {
1077 let ts: TokenStream = mac.node.tts.clone().into();
1078 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1081 id: ast::NodeId::new(0), // dummy value
1082 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1083 span: mac.span, // incorrect span, but shouldn't matter too much
1084 attrs: ThinVec::new(),
1091 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1092 let snippet = context.snippet(mac.span);
1093 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1094 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1095 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1097 if paren_pos < bracket_pos && paren_pos < brace_pos {
1099 } else if bracket_pos < brace_pos {
1106 /// Indent each line according to the specified `indent`.
1134 fn indent_macro_snippet(
1135 context: &RewriteContext,
1138 ) -> Option<String> {
1139 let mut lines = LineClasses::new(macro_str);
1140 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1141 let mut trimmed_lines = Vec::with_capacity(16);
1143 let mut veto_trim = false;
1144 let min_prefix_space_width = lines
1145 .filter_map(|(kind, line)| {
1146 let mut trimmed = true;
1147 let prefix_space_width = if is_empty_line(&line) {
1150 Some(get_prefix_space_width(context, &line))
1153 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1154 veto_trim = kind.is_string() && !line.ends_with('\\');
1158 line.trim().to_owned()
1160 trimmed_lines.push((trimmed, line, prefix_space_width));
1162 // when computing the minimum, do not consider lines within a string
1164 FullCodeCharKind::InString | FullCodeCharKind::EndString => None,
1165 _ => prefix_space_width,
1171 first_line + "\n" + &trimmed_lines
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() + original_indent_width
1178 .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 = 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(new_body, config.max_width(), shape)?;
1339 // Indent the body since it is in a block.
1340 let indent_str = body_indent.to_string(&config);
1341 let mut new_body = LineClasses::new(new_body.trim_right())
1343 (String::new(), true),
1344 |(mut s, need_indent), (kind, ref l)| {
1345 if !l.is_empty() && need_indent {
1348 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1353 // Undo our replacement of macro variables.
1354 // FIXME: this could be *much* more efficient.
1355 for (old, new) in &substs {
1356 if old_body.find(new).is_some() {
1357 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1360 new_body = new_body.replace(new, old);
1364 result += new_body.trim();
1365 } else if !new_body.is_empty() {
1367 result += &new_body;
1368 result += &shape.indent.to_string(&config);
1377 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1379 /// # Expected syntax
1383 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1384 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1386 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1389 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1390 let mut result = String::with_capacity(1024);
1391 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1392 let nested_shape = shape
1393 .block_indent(context.config.tab_spaces())
1394 .with_max_width(context.config);
1396 result.push_str("lazy_static! {");
1397 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1399 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1400 match parser.$method($($arg,)*) {
1402 if parser.sess.span_diagnostic.has_errors() {
1403 parser.sess.span_diagnostic.reset_err_count();
1411 parser.sess.span_diagnostic.reset_err_count();
1417 while parser.token != Token::Eof {
1418 // Parse a `lazy_static!` item.
1419 let vis = ::utils::format_visibility(context, &parse_or!(parse_visibility, false));
1420 parser.eat_keyword(symbol::keywords::Static);
1421 parser.eat_keyword(symbol::keywords::Ref);
1422 let id = parse_or!(parse_ident);
1423 parser.eat(&Token::Colon);
1424 let ty = parse_or!(parse_ty);
1425 parser.eat(&Token::Eq);
1426 let expr = parse_or!(parse_expr);
1427 parser.eat(&Token::Semi);
1429 // Rewrite as a static item.
1430 let mut stmt = String::with_capacity(128);
1431 stmt.push_str(&format!(
1432 "{}static ref {}: {} =",
1435 ty.rewrite(context, nested_shape)?
1437 result.push_str(&::expr::rewrite_assign_rhs(
1441 nested_shape.sub_width(1)?,
1444 if parser.token != Token::Eof {
1445 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1449 result.push_str(&shape.indent.to_string_with_newline(context.config));
1455 fn rewrite_macro_with_items(
1456 context: &RewriteContext,
1461 position: MacroPosition,
1463 ) -> Option<String> {
1464 let (opener, closer) = match style {
1465 DelimToken::Paren => ("(", ")"),
1466 DelimToken::Bracket => ("[", "]"),
1467 DelimToken::Brace => (" {", "}"),
1470 let trailing_semicolon = match style {
1471 DelimToken::Paren | DelimToken::Bracket if position == MacroPosition::Item => ";",
1475 let mut visitor = FmtVisitor::from_context(context);
1476 visitor.block_indent = shape.indent.block_indent(context.config);
1477 visitor.last_pos = context.snippet_provider.span_after(span, opener.trim());
1479 let item = match item {
1480 MacroArg::Item(item) => item,
1483 visitor.visit_item(&item);
1486 let mut result = String::with_capacity(256);
1487 result.push_str(¯o_name);
1488 result.push_str(opener);
1489 result.push_str(&visitor.block_indent.to_string_with_newline(context.config));
1490 result.push_str(visitor.buffer.trim());
1491 result.push_str(&shape.indent.to_string_with_newline(context.config));
1492 result.push_str(closer);
1493 result.push_str(trailing_semicolon);
1494 return Some(result);