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;
24 use syntax::codemap::{BytePos, Span};
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;
30 use syntax::tokenstream::{Cursor, ThinTokenStream, TokenStream, TokenTree};
31 use syntax::util::ThinVec;
33 use codemap::SpanUtils;
34 use comment::{contains_comment, remove_trailing_white_spaces, FindUncommented};
35 use expr::{rewrite_array, rewrite_call_inner};
36 use rewrite::{Rewrite, RewriteContext};
37 use shape::{Indent, Shape};
38 use utils::{format_visibility, mk_sp};
40 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
42 // FIXME: use the enum from libsyntax?
43 #[derive(Clone, Copy, PartialEq, Eq)]
50 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
51 pub enum MacroPosition {
59 fn opener(&self) -> &'static str {
61 MacroStyle::Parens => "(",
62 MacroStyle::Brackets => "[",
63 MacroStyle::Braces => "{",
74 impl Rewrite for MacroArg {
75 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
77 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
78 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
79 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
84 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
85 macro_rules! parse_macro_arg {
86 ($target:tt, $macro_arg:ident, $parser:ident) => {
87 let mut cloned_parser = (*parser).clone();
88 match cloned_parser.$parser() {
90 if parser.sess.span_diagnostic.has_errors() {
91 parser.sess.span_diagnostic.reset_err_count();
94 *parser = cloned_parser;
95 return Some(MacroArg::$macro_arg((*$target).clone()));
100 parser.sess.span_diagnostic.reset_err_count();
106 parse_macro_arg!(expr, Expr, parse_expr);
107 parse_macro_arg!(ty, Ty, parse_ty);
108 parse_macro_arg!(pat, Pat, parse_pat);
113 pub fn rewrite_macro(
115 extra_ident: Option<ast::Ident>,
116 context: &RewriteContext,
118 position: MacroPosition,
119 ) -> Option<String> {
120 let context = &mut context.clone();
121 context.inside_macro = true;
122 if context.config.use_try_shorthand() {
123 if let Some(expr) = convert_try_mac(mac, context) {
124 context.inside_macro = false;
125 return expr.rewrite(context, shape);
129 let original_style = macro_style(mac, context);
131 let macro_name = match extra_ident {
132 None => format!("{}!", mac.node.path),
134 if ident == symbol::keywords::Invalid.ident() {
135 format!("{}!", mac.node.path)
137 format!("{}! {}", mac.node.path, ident)
142 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
148 let ts: TokenStream = mac.node.stream();
149 if ts.is_empty() && !contains_comment(context.snippet(mac.span)) {
151 MacroStyle::Parens if position == MacroPosition::Item => {
152 Some(format!("{}();", macro_name))
154 MacroStyle::Parens => Some(format!("{}()", macro_name)),
155 MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
156 MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
160 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
161 let mut arg_vec = Vec::new();
162 let mut vec_with_semi = false;
163 let mut trailing_comma = false;
165 if MacroStyle::Braces != style {
167 match parse_macro_arg(&mut parser) {
168 Some(arg) => arg_vec.push(arg),
169 None => return Some(context.snippet(mac.span).to_owned()),
176 // Try to parse `vec![expr; expr]`
177 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
179 if parser.token != Token::Eof {
180 match parse_macro_arg(&mut parser) {
184 if parser.token == Token::Eof && arg_vec.len() == 2 {
185 vec_with_semi = true;
189 None => return Some(context.snippet(mac.span).to_owned()),
193 return Some(context.snippet(mac.span).to_owned());
195 _ => return Some(context.snippet(mac.span).to_owned()),
200 if parser.token == Token::Eof {
201 trailing_comma = true;
208 MacroStyle::Parens => {
209 // Format macro invocation as function call, forcing no trailing
210 // comma because not all macros support them.
214 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..],
217 context.config.width_heuristics().fn_call_width,
219 ).map(|rw| match position {
220 MacroPosition::Item => format!("{};", rw),
224 MacroStyle::Brackets => {
225 let mac_shape = shape.offset_left(macro_name.len())?;
226 // Handle special case: `vec![expr; expr]`
228 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
234 let total_overhead = lbr.len() + rbr.len() + 6;
235 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
236 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
237 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
238 if !lhs.contains('\n') && !rhs.contains('\n')
239 && lhs.len() + rhs.len() + total_overhead <= shape.width
241 Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
244 "{}{}\n{}{};\n{}{}\n{}{}",
247 nested_shape.indent.to_string(context.config),
249 nested_shape.indent.to_string(context.config),
251 shape.indent.to_string(context.config),
256 // If we are rewriting `vec!` macro or other special macros,
257 // then we can rewrite this as an usual array literal.
258 // Otherwise, we must preserve the original existence of trailing comma.
259 if FORCED_BRACKET_MACROS.contains(¯o_name.as_str()) {
260 context.inside_macro = false;
261 trailing_comma = false;
263 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
267 .span_after(mac.span, original_style.opener()),
268 mac.span.hi() - BytePos(1),
270 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..];
271 let rewrite = rewrite_array(arg_vec, sp, context, mac_shape, trailing_comma)?;
273 Some(format!("{}{}", macro_name, rewrite))
276 MacroStyle::Braces => {
277 // Skip macro invocations with braces, for now.
278 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
283 pub fn rewrite_macro_def(
284 context: &RewriteContext,
288 vis: &ast::Visibility,
290 ) -> Option<String> {
291 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
297 let mut parser = MacroParser::new(def.stream().into_trees());
298 let mut parsed_def = match parser.parse() {
300 None => return snippet,
303 // Only attempt to format function-like macros.
304 if parsed_def.branches.len() != 1 || parsed_def.branches[0].args_paren_kind != DelimToken::Paren
306 // FIXME(#1539): implement for non-sugared macros.
310 let branch = parsed_def.branches.remove(0);
311 let args_str = format_macro_args(branch.args)?;
313 // The macro body is the most interesting part. It might end up as various
314 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
315 // parsed as regular Rust code (and note that these can be escaped using
316 // `$$`). We'll try and format like an AST node, but we'll substitute
317 // variables for new names with the same length first.
319 let old_body = context.snippet(branch.body).trim();
320 let (body_str, substs) = replace_names(old_body);
322 // We'll hack the indent below, take this into account when formatting,
323 let mut config = context.config.clone();
324 let new_width = config.max_width() - indent.block_indent(&config).width();
325 config.set().max_width(new_width);
326 config.set().hide_parse_errors(true);
328 // First try to format as items, then as statements.
329 let new_body = match ::format_snippet(&body_str, &config) {
330 Some(new_body) => new_body,
331 None => match ::format_code_block(&body_str, &config) {
332 Some(new_body) => new_body,
333 None => return snippet,
337 // Indent the body since it is in a block.
338 let indent_str = indent.block_indent(&config).to_string(&config);
339 let mut new_body = new_body
345 format!("{}{}", indent_str, l)
351 // Undo our replacement of macro variables.
352 // FIXME: this could be *much* more efficient.
353 for (old, new) in substs.iter() {
354 if old_body.find(new).is_some() {
356 "rewrite_macro_def: bailing matching variable: `{}` in `{}`",
361 new_body = new_body.replace(new, old);
364 let result = format!(
365 "{}macro {}({}) {{\n{}\n{}}}",
366 format_visibility(vis),
370 indent.to_string(&context.config),
376 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
377 // aren't causing problems.
378 // This should also work for escaped `$` variables, where we leave earlier `$`s.
379 fn replace_names(input: &str) -> (String, HashMap<String, String>) {
380 // Each substitution will require five or six extra bytes.
381 let mut result = String::with_capacity(input.len() + 64);
382 let mut substs = HashMap::new();
383 let mut dollar_count = 0;
384 let mut cur_name = String::new();
386 for c in input.chars() {
389 } else if dollar_count == 0 {
391 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
392 // Terminates a name following one or more dollars.
393 let mut new_name = String::new();
394 let mut old_name = String::new();
396 for _ in 0..(dollar_count - 1) {
401 new_name.push_str(&cur_name);
402 old_name.push_str(&cur_name);
404 result.push_str(&new_name);
405 substs.insert(old_name, new_name);
410 cur_name = String::new();
411 } else if c.is_alphanumeric() {
416 // FIXME: duplicate code
417 if !cur_name.is_empty() {
418 let mut new_name = String::new();
419 let mut old_name = String::new();
421 for _ in 0..(dollar_count - 1) {
426 new_name.push_str(&cur_name);
427 old_name.push_str(&cur_name);
429 result.push_str(&new_name);
430 substs.insert(old_name, new_name);
433 debug!("replace_names `{}` {:?}", result, substs);
438 // This is a bit sketchy. The token rules probably need tweaking, but it works
439 // for some common cases. I hope the basic logic is sufficient. Note that the
440 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
441 // and `(`/`)` have special meaning.
443 // We always try and format on one line.
444 fn format_macro_args(toks: ThinTokenStream) -> Option<String> {
445 let mut result = String::with_capacity(128);
446 let mut insert_space = SpaceState::Never;
448 for tok in (toks.into(): TokenStream).trees() {
450 TokenTree::Token(_, t) => {
451 if !result.is_empty() && force_space_before(&t) {
452 insert_space = SpaceState::Always;
454 if force_no_space_before(&t) {
455 insert_space = SpaceState::Never;
457 match (insert_space, ident_like(&t)) {
458 (SpaceState::Always, _)
459 | (SpaceState::Punctuation, false)
460 | (SpaceState::Ident, true) => {
465 result.push_str(&pprust::token_to_string(&t));
466 insert_space = next_space(&t);
468 TokenTree::Delimited(_, d) => {
469 let formatted = format_macro_args(d.tts)?;
471 SpaceState::Always => {
477 DelimToken::Paren => {
478 result.push_str(&format!("({})", formatted));
479 insert_space = SpaceState::Always;
481 DelimToken::Bracket => {
482 result.push_str(&format!("[{}]", formatted));
483 insert_space = SpaceState::Always;
485 DelimToken::Brace => {
486 result.push_str(&format!(" {{ {} }}", formatted));
487 insert_space = SpaceState::Always;
489 DelimToken::NoDelim => {
490 result.push_str(&format!("{}", formatted));
491 insert_space = SpaceState::Always;
501 // We should insert a space if the next token is a:
502 #[derive(Copy, Clone)]
506 Ident, // Or ident/literal-like thing.
510 fn force_space_before(tok: &Token) -> bool {
529 | Token::Dollar => true,
530 Token::BinOp(bot) => bot != BinOpToken::Star,
535 fn force_no_space_before(tok: &Token) -> bool {
537 Token::Semi | Token::Comma | Token::Dot => true,
538 Token::BinOp(bot) => bot == BinOpToken::Star,
542 fn ident_like(tok: &Token) -> bool {
544 Token::Ident(_) | Token::Literal(..) | Token::Lifetime(_) => true,
549 fn next_space(tok: &Token) -> SpaceState {
562 | Token::BinOp(_) => SpaceState::Punctuation,
567 | Token::OpenDelim(_)
568 | Token::CloseDelim(_)
569 | Token::Whitespace => SpaceState::Never,
571 Token::Literal(..) | Token::Ident(_) | Token::Lifetime(_) => SpaceState::Ident,
573 _ => SpaceState::Always,
577 /// Tries to convert a macro use into a short hand try expression. Returns None
578 /// when the macro is not an instance of try! (or parsing the inner expression
580 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
581 if &format!("{}", mac.node.path)[..] == "try" {
582 let ts: TokenStream = mac.node.tts.clone().into();
583 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
586 id: ast::NodeId::new(0), // dummy value
587 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
588 span: mac.span, // incorrect span, but shouldn't matter too much
589 attrs: ThinVec::new(),
596 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
597 let snippet = context.snippet(mac.span);
598 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
599 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
600 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
602 if paren_pos < bracket_pos && paren_pos < brace_pos {
604 } else if bracket_pos < brace_pos {
611 /// Indent each line according to the specified `indent`.
636 fn indent_macro_snippet(
637 context: &RewriteContext,
640 ) -> Option<String> {
641 let mut lines = macro_str.lines();
642 let first_line = lines.next().map(|s| s.trim_right())?;
643 let mut trimmed_lines = Vec::with_capacity(16);
645 let min_prefix_space_width = lines
647 let prefix_space_width = if is_empty_line(line) {
650 Some(get_prefix_space_width(context, line))
652 trimmed_lines.push((line.trim(), prefix_space_width));
658 String::from(first_line) + "\n"
661 .map(|&(line, prefix_space_width)| match prefix_space_width {
662 Some(original_indent_width) => {
663 let new_indent_width = indent.width()
664 + original_indent_width
665 .checked_sub(min_prefix_space_width)
667 let new_indent = Indent::from_width(context.config, new_indent_width);
668 format!("{}{}", new_indent.to_string(context.config), line.trim())
670 None => String::new(),
677 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
682 '\t' => width += context.config.tab_spaces(),
689 fn is_empty_line(s: &str) -> bool {
690 s.is_empty() || s.chars().all(char::is_whitespace)
693 // A very simple parser that just parses a macros 2.0 definition into its branches.
694 // Currently we do not attempt to parse any further than that.
701 // (`(` ... `)` `=>` `{` ... `}`)*
702 fn parse(&mut self) -> Option<Macro> {
703 let mut branches = vec![];
704 while self.toks.look_ahead(1).is_some() {
705 branches.push(self.parse_branch()?);
708 Some(Macro { branches })
711 // `(` ... `)` `=>` `{` ... `}`
712 fn parse_branch(&mut self) -> Option<MacroBranch> {
713 let (args_paren_kind, args) = match self.toks.next()? {
714 TokenTree::Token(..) => return None,
715 TokenTree::Delimited(_, ref d) => (d.delim, d.tts.clone().into()),
717 match self.toks.next()? {
718 TokenTree::Token(_, Token::FatArrow) => {}
721 let body = match self.toks.next()? {
722 TokenTree::Token(..) => return None,
723 TokenTree::Delimited(sp, _) => {
724 let data = sp.data();
725 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt)
736 // A parsed macros 2.0 macro definition.
738 branches: Vec<MacroBranch>,
741 // FIXME: it would be more efficient to use references to the token streams
742 // rather than clone them, if we can make the borrowing work out.
744 args: ThinTokenStream,
745 args_paren_kind: DelimToken,
752 use syntax::parse::{parse_stream_from_source_str, ParseSess};
753 use syntax::codemap::{FileName, FilePathMapping};
755 fn format_macro_args_str(s: &str) -> String {
756 let input = parse_stream_from_source_str(
757 FileName::Custom("stdin".to_owned()),
759 &ParseSess::new(FilePathMapping::empty()),
762 format_macro_args(input.into()).unwrap()
766 fn test_format_macro_args() {
767 assert_eq!(format_macro_args_str(""), "".to_owned());
768 assert_eq!(format_macro_args_str("$ x : ident"), "$x: ident".to_owned());
770 format_macro_args_str("$ m1 : ident , $ m2 : ident , $ x : ident"),
771 "$m1: ident, $m2: ident, $x: ident".to_owned()
774 format_macro_args_str("$($beginning:ident),*;$middle:ident;$($end:ident),*"),
775 "$($beginning: ident),*; $middle: ident; $($end: ident),*".to_owned()
778 format_macro_args_str(
779 "$ name : ident ( $ ( $ dol : tt $ var : ident ) * ) $ ( $ body : tt ) *"
781 "$name: ident($($dol: tt $var: ident)*) $($body: tt)*".to_owned()