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 syntax::codemap::{mk_sp, BytePos};
24 use syntax::parse::token::Token;
25 use syntax::parse::tts_to_parser;
27 use syntax::util::ThinVec;
30 use codemap::SpanUtils;
31 use rewrite::{Rewrite, RewriteContext};
32 use expr::{rewrite_call, rewrite_array};
33 use comment::{FindUncommented, contains_comment};
35 const FORCED_BRACKET_MACROS: &'static [&'static str] = &["vec!"];
37 // FIXME: use the enum from libsyntax?
38 #[derive(Clone, Copy, PartialEq, Eq)]
45 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
46 pub enum MacroPosition {
53 fn opener(&self) -> &'static str {
55 MacroStyle::Parens => "(",
56 MacroStyle::Brackets => "[",
57 MacroStyle::Braces => "{",
62 pub fn rewrite_macro(mac: &ast::Mac,
63 extra_ident: Option<ast::Ident>,
64 context: &RewriteContext,
66 position: MacroPosition)
68 if context.config.use_try_shorthand {
69 if let Some(expr) = convert_try_mac(mac, context) {
70 return expr.rewrite(context, shape);
74 let original_style = macro_style(mac, context);
76 let macro_name = match extra_ident {
77 None => format!("{}!", mac.node.path),
79 if ident == symbol::keywords::Invalid.ident() {
80 format!("{}!", mac.node.path)
82 format!("{}! {}", mac.node.path, ident)
87 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
93 if mac.node.tts.is_empty() && !contains_comment(&context.snippet(mac.span)) {
95 MacroStyle::Parens if position == MacroPosition::Item => {
96 Some(format!("{}();", macro_name))
98 MacroStyle::Parens => Some(format!("{}()", macro_name)),
99 MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
100 MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
104 let mut parser = tts_to_parser(context.parse_session, mac.node.tts.clone());
105 let mut expr_vec = Vec::new();
107 if MacroStyle::Braces != style {
109 let expr = match parser.parse_expr() {
112 if context.parse_session.span_diagnostic.has_errors() {
134 if parser.token == Token::Eof {
135 // vec! is a special case of bracket macro which should be formated as an array.
136 if macro_name == "vec!" {
146 MacroStyle::Parens => {
147 // Format macro invocation as function call, forcing no trailing
148 // comma because not all macros support them.
149 rewrite_call(context, ¯o_name, &expr_vec, mac.span, shape, true)
150 .map(|rw| match position {
151 MacroPosition::Item => format!("{};", rw),
155 MacroStyle::Brackets => {
156 // Format macro invocation as array literal.
157 let extra_offset = macro_name.len();
158 let shape = try_opt!(shape.shrink_left(extra_offset));
159 let rewrite = try_opt!(rewrite_array(expr_vec.iter().map(|x| &**x),
162 .span_after(mac.span,
165 mac.span.hi - BytePos(1)),
169 Some(format!("{}{}", macro_name, rewrite))
171 MacroStyle::Braces => {
172 // Skip macro invocations with braces, for now.
178 /// Tries to convert a macro use into a short hand try expression. Returns None
179 /// when the macro is not an instance of try! (or parsing the inner expression
181 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
182 if &format!("{}", mac.node.path)[..] == "try" {
183 let mut parser = tts_to_parser(context.parse_session, mac.node.tts.clone());
186 id: ast::NodeId::new(0), // dummy value
187 node: ast::ExprKind::Try(try_opt!(parser.parse_expr().ok())),
188 span: mac.span, // incorrect span, but shouldn't matter too much
189 attrs: ThinVec::new(),
196 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
197 let snippet = context.snippet(mac.span);
198 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
199 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
200 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
202 if paren_pos < bracket_pos && paren_pos < brace_pos {
204 } else if bracket_pos < brace_pos {