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;
26 use syntax::codemap::{BytePos, Span};
27 use syntax::parse::new_parser_from_tts;
28 use syntax::parse::parser::Parser;
29 use syntax::parse::token::{BinOpToken, DelimToken, Token};
30 use syntax::print::pprust;
32 use syntax::tokenstream::{Cursor, ThinTokenStream, TokenStream, TokenTree};
33 use syntax::util::ThinVec;
35 use codemap::SpanUtils;
36 use comment::{contains_comment, remove_trailing_white_spaces, FindUncommented};
37 use expr::{rewrite_array, rewrite_call_inner};
38 use lists::{itemize_list, write_list, ListFormatting};
39 use rewrite::{Rewrite, RewriteContext};
40 use shape::{Indent, Shape};
41 use utils::{format_visibility, mk_sp};
43 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
45 // FIXME: use the enum from libsyntax?
46 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
53 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
54 pub enum MacroPosition {
62 fn opener(&self) -> &'static str {
64 MacroStyle::Parens => "(",
65 MacroStyle::Brackets => "[",
66 MacroStyle::Braces => "{",
78 impl Rewrite for MacroArg {
79 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
81 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
82 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
83 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
88 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
89 macro_rules! parse_macro_arg {
90 ($macro_arg: ident, $parser: ident) => {
91 let mut cloned_parser = (*parser).clone();
92 match cloned_parser.$parser() {
94 if parser.sess.span_diagnostic.has_errors() {
95 parser.sess.span_diagnostic.reset_err_count();
98 *parser = cloned_parser;
99 return Some(MacroArg::$macro_arg((*x).clone()));
104 parser.sess.span_diagnostic.reset_err_count();
110 parse_macro_arg!(Expr, parse_expr);
111 parse_macro_arg!(Ty, parse_ty);
112 parse_macro_arg!(Pat, parse_pat);
117 pub fn rewrite_macro(
119 extra_ident: Option<ast::Ident>,
120 context: &RewriteContext,
122 position: MacroPosition,
123 ) -> Option<String> {
124 let context = &mut context.clone();
125 context.inside_macro = true;
126 if context.config.use_try_shorthand() {
127 if let Some(expr) = convert_try_mac(mac, context) {
128 context.inside_macro = false;
129 return expr.rewrite(context, shape);
133 let original_style = macro_style(mac, context);
135 let macro_name = match extra_ident {
136 None => format!("{}!", mac.node.path),
138 if ident == symbol::keywords::Invalid.ident() {
139 format!("{}!", mac.node.path)
141 format!("{}! {}", mac.node.path, ident)
146 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
152 let ts: TokenStream = mac.node.stream();
153 if ts.is_empty() && !contains_comment(context.snippet(mac.span)) {
155 MacroStyle::Parens if position == MacroPosition::Item => {
156 Some(format!("{}();", macro_name))
158 MacroStyle::Parens => Some(format!("{}()", macro_name)),
159 MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
160 MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
164 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
165 let mut arg_vec = Vec::new();
166 let mut vec_with_semi = false;
167 let mut trailing_comma = false;
169 if MacroStyle::Braces != style {
171 match parse_macro_arg(&mut parser) {
172 Some(arg) => arg_vec.push(arg),
173 None => return Some(context.snippet(mac.span).to_owned()),
180 // Try to parse `vec![expr; expr]`
181 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
183 if parser.token != Token::Eof {
184 match parse_macro_arg(&mut parser) {
188 if parser.token == Token::Eof && arg_vec.len() == 2 {
189 vec_with_semi = true;
193 None => return Some(context.snippet(mac.span).to_owned()),
197 return Some(context.snippet(mac.span).to_owned());
199 _ => return Some(context.snippet(mac.span).to_owned()),
204 if parser.token == Token::Eof {
205 trailing_comma = true;
212 MacroStyle::Parens => {
213 // Format macro invocation as function call, forcing no trailing
214 // comma because not all macros support them.
218 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..],
221 context.config.width_heuristics().fn_call_width,
223 ).map(|rw| match position {
224 MacroPosition::Item => format!("{};", rw),
228 MacroStyle::Brackets => {
229 let mac_shape = shape.offset_left(macro_name.len())?;
230 // Handle special case: `vec![expr; expr]`
232 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
238 let total_overhead = lbr.len() + rbr.len() + 6;
239 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
240 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
241 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
242 if !lhs.contains('\n') && !rhs.contains('\n')
243 && lhs.len() + rhs.len() + total_overhead <= shape.width
245 Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
248 "{}{}\n{}{};\n{}{}\n{}{}",
251 nested_shape.indent.to_string(context.config),
253 nested_shape.indent.to_string(context.config),
255 shape.indent.to_string(context.config),
260 // If we are rewriting `vec!` macro or other special macros,
261 // then we can rewrite this as an usual array literal.
262 // Otherwise, we must preserve the original existence of trailing comma.
263 if FORCED_BRACKET_MACROS.contains(¯o_name.as_str()) {
264 context.inside_macro = false;
265 trailing_comma = false;
267 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
271 .span_after(mac.span, original_style.opener()),
272 mac.span.hi() - BytePos(1),
274 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..];
275 let rewrite = rewrite_array(arg_vec, sp, context, mac_shape, trailing_comma)?;
277 Some(format!("{}{}", macro_name, rewrite))
280 MacroStyle::Braces => {
281 // Skip macro invocations with braces, for now.
282 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
287 pub fn rewrite_macro_def(
288 context: &RewriteContext,
293 vis: &ast::Visibility,
295 ) -> Option<String> {
296 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
297 if snippet.as_ref().map_or(true, |s| s.ends_with(";")) {
301 let mut parser = MacroParser::new(def.stream().into_trees());
302 let parsed_def = match parser.parse() {
304 None => return snippet,
307 let mut result = if def.legacy {
308 String::from("macro_rules!")
310 format!("{}macro", format_visibility(vis))
314 result += &ident.name.as_str();
316 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
318 let arm_shape = if multi_branch_style {
320 .block_indent(context.config.tab_spaces())
321 .with_max_width(context.config)
326 let branch_items = itemize_list(
328 parsed_def.branches.iter(),
331 |branch| branch.span.lo(),
332 |branch| branch.span.hi(),
333 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
334 context.codemap.span_after(span, "{"),
337 ).collect::<Vec<_>>();
339 let fmt = ListFormatting {
340 tactic: DefinitiveListTactic::Vertical,
341 separator: if def.legacy { ";" } else { "" },
342 trailing_separator: SeparatorTactic::Always,
343 separator_place: SeparatorPlace::Back,
345 ends_with_newline: true,
346 preserve_newline: true,
347 config: context.config,
350 if multi_branch_style {
352 result += &arm_shape.indent.to_string(context.config);
355 result += write_list(&branch_items, &fmt)?.as_str();
357 if multi_branch_style {
359 result += &indent.to_string(context.config);
366 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
367 // aren't causing problems.
368 // This should also work for escaped `$` variables, where we leave earlier `$`s.
369 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
370 // Each substitution will require five or six extra bytes.
371 let mut result = String::with_capacity(input.len() + 64);
372 let mut substs = HashMap::new();
373 let mut dollar_count = 0;
374 let mut cur_name = String::new();
376 for c in input.chars() {
379 } else if dollar_count == 0 {
381 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
382 // Terminates a name following one or more dollars.
383 let mut new_name = String::new();
384 let mut old_name = String::new();
386 for _ in 0..(dollar_count - 1) {
391 new_name.push_str(&cur_name);
392 old_name.push_str(&cur_name);
394 result.push_str(&new_name);
395 substs.insert(old_name, new_name);
400 cur_name = String::new();
401 } else if c == '(' && cur_name.is_empty() {
402 // FIXME: Support macro def with repeat.
404 } else if c.is_alphanumeric() {
409 // FIXME: duplicate code
410 if !cur_name.is_empty() {
411 let mut new_name = String::new();
412 let mut old_name = String::new();
414 for _ in 0..(dollar_count - 1) {
419 new_name.push_str(&cur_name);
420 old_name.push_str(&cur_name);
422 result.push_str(&new_name);
423 substs.insert(old_name, new_name);
426 debug!("replace_names `{}` {:?}", result, substs);
428 Some((result, substs))
431 // This is a bit sketchy. The token rules probably need tweaking, but it works
432 // for some common cases. I hope the basic logic is sufficient. Note that the
433 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
434 // and `(`/`)` have special meaning.
436 // We always try and format on one line.
437 // FIXME: Use multi-line when every thing does not fit on one line.
438 fn format_macro_args(toks: ThinTokenStream, shape: Shape) -> Option<String> {
439 let mut result = String::with_capacity(128);
440 let mut insert_space = SpaceState::Never;
442 for tok in (toks.into(): TokenStream).trees() {
444 TokenTree::Token(_, t) => {
445 if !result.is_empty() && force_space_before(&t) {
446 insert_space = SpaceState::Always;
448 if force_no_space_before(&t) {
449 insert_space = SpaceState::Never;
451 match (insert_space, ident_like(&t)) {
452 (SpaceState::Always, _)
453 | (SpaceState::Punctuation, false)
454 | (SpaceState::Ident, true) => {
459 result.push_str(&pprust::token_to_string(&t));
460 insert_space = next_space(&t);
462 TokenTree::Delimited(_, d) => {
463 if let SpaceState::Always = insert_space {
466 let formatted = format_macro_args(d.tts, shape)?;
468 DelimToken::Paren => {
469 result.push_str(&format!("({})", formatted));
470 insert_space = SpaceState::Always;
472 DelimToken::Bracket => {
473 result.push_str(&format!("[{}]", formatted));
474 insert_space = SpaceState::Always;
476 DelimToken::Brace => {
477 result.push_str(&format!(" {{ {} }}", formatted));
478 insert_space = SpaceState::Always;
480 DelimToken::NoDelim => {
481 result.push_str(&format!("{}", formatted));
482 insert_space = SpaceState::Always;
489 if result.len() <= shape.width {
496 // We should insert a space if the next token is a:
497 #[derive(Copy, Clone)]
501 Ident, // Or ident/literal-like thing.
505 fn force_space_before(tok: &Token) -> bool {
524 | Token::Dollar => true,
525 Token::BinOp(bot) => bot != BinOpToken::Star,
530 fn force_no_space_before(tok: &Token) -> bool {
532 Token::Semi | Token::Comma | Token::Dot => true,
533 Token::BinOp(bot) => bot == BinOpToken::Star,
537 fn ident_like(tok: &Token) -> bool {
539 Token::Ident(_) | Token::Literal(..) | Token::Lifetime(_) => true,
544 fn next_space(tok: &Token) -> SpaceState {
557 | Token::BinOp(_) => SpaceState::Punctuation,
562 | Token::OpenDelim(_)
563 | Token::CloseDelim(_)
564 | Token::Whitespace => SpaceState::Never,
566 Token::Literal(..) | Token::Ident(_) | Token::Lifetime(_) => SpaceState::Ident,
568 _ => SpaceState::Always,
572 /// Tries to convert a macro use into a short hand try expression. Returns None
573 /// when the macro is not an instance of try! (or parsing the inner expression
575 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
576 if &format!("{}", mac.node.path)[..] == "try" {
577 let ts: TokenStream = mac.node.tts.clone().into();
578 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
581 id: ast::NodeId::new(0), // dummy value
582 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
583 span: mac.span, // incorrect span, but shouldn't matter too much
584 attrs: ThinVec::new(),
591 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
592 let snippet = context.snippet(mac.span);
593 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
594 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
595 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
597 if paren_pos < bracket_pos && paren_pos < brace_pos {
599 } else if bracket_pos < brace_pos {
606 /// Indent each line according to the specified `indent`.
631 fn indent_macro_snippet(
632 context: &RewriteContext,
635 ) -> Option<String> {
636 let mut lines = macro_str.lines();
637 let first_line = lines.next().map(|s| s.trim_right())?;
638 let mut trimmed_lines = Vec::with_capacity(16);
640 let min_prefix_space_width = lines
642 let prefix_space_width = if is_empty_line(line) {
645 Some(get_prefix_space_width(context, line))
647 trimmed_lines.push((line.trim(), prefix_space_width));
653 String::from(first_line) + "\n"
656 .map(|&(line, prefix_space_width)| match prefix_space_width {
657 Some(original_indent_width) => {
658 let new_indent_width = indent.width()
659 + original_indent_width
660 .checked_sub(min_prefix_space_width)
662 let new_indent = Indent::from_width(context.config, new_indent_width);
663 format!("{}{}", new_indent.to_string(context.config), line.trim())
665 None => String::new(),
672 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
677 '\t' => width += context.config.tab_spaces(),
684 fn is_empty_line(s: &str) -> bool {
685 s.is_empty() || s.chars().all(char::is_whitespace)
688 // A very simple parser that just parses a macros 2.0 definition into its branches.
689 // Currently we do not attempt to parse any further than that.
696 // (`(` ... `)` `=>` `{` ... `}`)*
697 fn parse(&mut self) -> Option<Macro> {
698 let mut branches = vec![];
699 while self.toks.look_ahead(1).is_some() {
700 branches.push(self.parse_branch()?);
703 Some(Macro { branches })
706 // `(` ... `)` `=>` `{` ... `}`
707 fn parse_branch(&mut self) -> Option<MacroBranch> {
708 let tok = self.toks.next()?;
709 let (lo, args_paren_kind) = match tok {
710 TokenTree::Token(..) => return None,
711 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
713 let args = tok.joint().into();
714 match self.toks.next()? {
715 TokenTree::Token(_, Token::FatArrow) => {}
718 let (mut hi, body) = match self.toks.next()? {
719 TokenTree::Token(..) => return None,
720 TokenTree::Delimited(sp, _) => {
721 let data = sp.data();
724 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
728 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
741 // A parsed macros 2.0 macro definition.
743 branches: Vec<MacroBranch>,
746 // FIXME: it would be more efficient to use references to the token streams
747 // rather than clone them, if we can make the borrowing work out.
750 args_paren_kind: DelimToken,
751 args: ThinTokenStream,
758 context: &RewriteContext,
760 multi_branch_style: bool,
761 ) -> Option<String> {
762 // Only attempt to format function-like macros.
763 if self.args_paren_kind != DelimToken::Paren {
764 // FIXME(#1539): implement for non-sugared macros.
769 let mut result = format_macro_args(self.args.clone(), shape.sub_width(5)?)?;
771 if multi_branch_style {
775 // The macro body is the most interesting part. It might end up as various
776 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
777 // parsed as regular Rust code (and note that these can be escaped using
778 // `$$`). We'll try and format like an AST node, but we'll substitute
779 // variables for new names with the same length first.
781 let old_body = context.snippet(self.body).trim();
782 let (body_str, substs) = replace_names(old_body)?;
784 let mut config = context.config.clone();
785 config.set().hide_parse_errors(true);
789 let has_block_body = old_body.starts_with('{');
791 let body_indent = if has_block_body {
794 // We'll hack the indent below, take this into account when formatting,
795 let body_indent = shape.indent.block_indent(&config);
796 let new_width = config.max_width() - body_indent.width();
797 config.set().max_width(new_width);
801 // First try to format as items, then as statements.
802 let new_body = match ::format_snippet(&body_str, &config) {
803 Some(new_body) => new_body,
804 None => match ::format_code_block(&body_str, &config) {
805 Some(new_body) => new_body,
810 // Indent the body since it is in a block.
811 let indent_str = body_indent.to_string(&config);
812 let mut new_body = new_body
815 .fold(String::new(), |mut s, l| {
822 // Undo our replacement of macro variables.
823 // FIXME: this could be *much* more efficient.
824 for (old, new) in &substs {
825 if old_body.find(new).is_some() {
826 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
829 new_body = new_body.replace(new, old);
833 result += new_body.trim();
834 } else if !new_body.is_empty() {
837 result += &shape.indent.to_string(&config);
849 use syntax::parse::{parse_stream_from_source_str, ParseSess};
850 use syntax::codemap::{FileName, FilePathMapping};
852 fn format_macro_args_str(s: &str) -> String {
853 let input = parse_stream_from_source_str(
854 FileName::Custom("stdin".to_owned()),
856 &ParseSess::new(FilePathMapping::empty()),
861 indent: Indent::empty(),
864 format_macro_args(input.into(), shape).unwrap()
868 fn test_format_macro_args() {
869 assert_eq!(format_macro_args_str(""), "".to_owned());
870 assert_eq!(format_macro_args_str("$ x : ident"), "$x: ident".to_owned());
872 format_macro_args_str("$ m1 : ident , $ m2 : ident , $ x : ident"),
873 "$m1: ident, $m2: ident, $x: ident".to_owned()
876 format_macro_args_str("$($beginning:ident),*;$middle:ident;$($end:ident),*"),
877 "$($beginning: ident),*; $middle: ident; $($end: ident),*".to_owned()
880 format_macro_args_str(
881 "$ name : ident ( $ ( $ dol : tt $ var : ident ) * ) $ ( $ body : tt ) *"
883 "$name: ident($($dol: tt $var: ident)*) $($body: tt)*".to_owned()