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.
23 use std::collections::hash_map::{HashMap, Entry};
26 use syntax::parse::token::{Eof, Comma, Token};
27 use syntax::parse::{ParseSess, tts_to_parser};
28 use syntax::codemap::{mk_sp, BytePos};
29 use syntax::parse::token;
30 use syntax::util::interner::StrInterner;
33 use rewrite::RewriteContext;
34 use expr::{rewrite_call, rewrite_array};
35 use comment::FindUncommented;
36 use utils::{wrap_str, span_after};
38 static FORCED_BRACKET_MACROS: &'static [&'static str] = &["vec!"];
40 // We need to pass `TokenTree`s to our expression parsing thread, but they are
41 // not `Send`. We wrap them in a `Send` container to force our will.
42 // FIXME: this is a pretty terrible hack. Any other solution would be preferred.
43 struct ForceSend<T>(pub T);
44 unsafe impl<T> Send for ForceSend<T> {}
46 // FIXME: use the enum from libsyntax?
47 #[derive(Clone, Copy)]
55 fn opener(&self) -> &'static str {
57 MacroStyle::Parens => "(",
58 MacroStyle::Brackets => "[",
59 MacroStyle::Braces => "{",
64 pub fn rewrite_macro(mac: &ast::Mac,
65 context: &RewriteContext,
69 let original_style = macro_style(mac, context);
70 let macro_name = format!("{}!", mac.node.path);
71 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
77 if let MacroStyle::Braces = style {
79 } else if mac.node.tts.is_empty() {
80 return if let MacroStyle::Parens = style {
81 Some(format!("{}()", macro_name))
83 Some(format!("{}[]", macro_name))
87 let wrapped_tt_vec = ForceSend(mac.node.tts.clone());
88 let my_interner = ForceSend(clone_interner());
90 // Wrap expression parsing logic in a thread since the libsyntax parser
91 // panics on failure, which we do not want to propagate.
92 // The expression vector is wrapped in an Option inside a Result.
93 let expr_vec_result = thread::spawn(move || {
94 let parse_session = ParseSess::new();
95 let mut parser = tts_to_parser(&parse_session, wrapped_tt_vec.0, vec![]);
96 let mut expr_vec = vec![];
97 token::get_ident_interner().reset(my_interner.0);
100 expr_vec.push(parser.parse_expr());
105 _ => panic!("Macro not list-like, skiping..."),
108 let _ = parser.bump();
110 if parser.token == Token::Eof {
115 Some(ForceSend((expr_vec, clone_interner())))
117 let (expr_vec, interner) = try_opt!(try_opt!(expr_vec_result.join().ok())).0;
118 token::get_ident_interner().reset(interner);
121 MacroStyle::Parens => {
122 // Format macro invocation as function call.
123 rewrite_call(context, ¯o_name, &expr_vec, mac.span, width, offset)
125 MacroStyle::Brackets => {
126 // Format macro invocation as array literal.
127 let extra_offset = macro_name.len();
128 let rewrite = try_opt!(rewrite_array(expr_vec.iter().map(|x| &**x),
129 mk_sp(span_after(mac.span,
130 original_style.opener(),
132 mac.span.hi - BytePos(1)),
134 try_opt!(width.checked_sub(extra_offset)),
135 offset + extra_offset));
137 Some(format!("{}{}", macro_name, rewrite))
139 MacroStyle::Braces => {
140 // Skip macro invocations with braces, for now.
141 wrap_str(context.snippet(mac.span),
142 context.config.max_width,
149 fn clone_interner() -> StrInterner {
150 let old = token::get_ident_interner();
151 let new = StrInterner::new();
152 let mut map = HashMap::new();
153 for name in (0..old.len()).map(|i| i as u32).map(ast::Name) {
154 match map.entry(old.get(name)) {
155 Entry::Occupied(e) => {
156 new.gensym_copy(*e.get());
158 Entry::Vacant(e) => {
159 e.insert(new.intern(&old.get(name)));
166 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
167 let snippet = context.snippet(mac.span);
168 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
169 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
170 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
172 if paren_pos < bracket_pos && paren_pos < brace_pos {
174 } else if bracket_pos < brace_pos {