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::BytePos;
24 use syntax::parse::token::Token;
25 use syntax::parse::new_parser_from_tts;
26 use syntax::tokenstream::TokenStream;
28 use syntax::util::ThinVec;
31 use codemap::SpanUtils;
32 use rewrite::{Rewrite, RewriteContext};
33 use expr::{rewrite_call, rewrite_array};
34 use comment::{FindUncommented, contains_comment};
37 const FORCED_BRACKET_MACROS: &'static [&'static str] = &["vec!"];
39 // FIXME: use the enum from libsyntax?
40 #[derive(Clone, Copy, PartialEq, Eq)]
47 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
48 pub enum MacroPosition {
55 fn opener(&self) -> &'static str {
57 MacroStyle::Parens => "(",
58 MacroStyle::Brackets => "[",
59 MacroStyle::Braces => "{",
66 extra_ident: Option<ast::Ident>,
67 context: &RewriteContext,
69 position: MacroPosition,
71 let mut context = &mut context.clone();
72 context.inside_macro = true;
73 if context.config.use_try_shorthand() {
74 if let Some(expr) = convert_try_mac(mac, context) {
75 return expr.rewrite(context, shape);
79 let original_style = macro_style(mac, context);
81 let macro_name = match extra_ident {
82 None => format!("{}!", mac.node.path),
84 if ident == symbol::keywords::Invalid.ident() {
85 format!("{}!", mac.node.path)
87 format!("{}! {}", mac.node.path, ident)
92 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
98 let ts: TokenStream = mac.node.tts.clone().into();
99 if ts.is_empty() && !contains_comment(&context.snippet(mac.span)) {
101 MacroStyle::Parens if position == MacroPosition::Item => {
102 Some(format!("{}();", macro_name))
104 MacroStyle::Parens => Some(format!("{}()", macro_name)),
105 MacroStyle::Brackets => Some(format!("{}[]", macro_name)),
106 MacroStyle::Braces => Some(format!("{}{{}}", macro_name)),
110 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
111 let mut expr_vec = Vec::new();
112 let mut vec_with_semi = false;
114 if MacroStyle::Braces != style {
116 let expr = match parser.parse_expr() {
119 if context.parse_session.span_diagnostic.has_errors() {
120 return Some(context.snippet(mac.span));
127 return Some(context.snippet(mac.span));
137 // Try to parse `vec![expr; expr]`
138 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
140 if parser.token != Token::Eof {
141 match parser.parse_expr() {
143 if context.parse_session.span_diagnostic.has_errors() {
148 if parser.token == Token::Eof && expr_vec.len() == 2 {
149 vec_with_semi = true;
153 Err(mut e) => e.cancel(),
164 if parser.token == Token::Eof {
165 // vec! is a special case of bracket macro which should be formated as an array.
166 if macro_name == "vec!" {
176 MacroStyle::Parens => {
177 // Format macro invocation as function call, forcing no trailing
178 // comma because not all macros support them.
179 rewrite_call(context, ¯o_name, &expr_vec, mac.span, shape).map(
180 |rw| match position {
181 MacroPosition::Item => format!("{};", rw),
186 MacroStyle::Brackets => {
187 let mac_shape = try_opt!(shape.shrink_left(macro_name.len()));
188 // Handle special case: `vec![expr; expr]`
190 let (lbr, rbr) = if context.config.spaces_within_square_brackets() {
196 let total_overhead = lbr.len() + rbr.len() + 6;
197 let lhs = try_opt!(expr_vec[0].rewrite(context, mac_shape));
198 let rhs = try_opt!(expr_vec[1].rewrite(context, mac_shape));
199 if !lhs.contains('\n') && !rhs.contains('\n') &&
200 lhs.len() + rhs.len() + total_overhead <= shape.width
202 Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
204 let nested_indent = shape.indent.block_indent(context.config);
206 "{}{}\n{}{};\n{}{}\n{}{}",
209 nested_indent.to_string(context.config),
211 nested_indent.to_string(context.config),
213 shape.indent.to_string(context.config),
218 // Format macro invocation as array literal.
219 let rewrite = try_opt!(rewrite_array(
220 expr_vec.iter().map(|x| &**x),
222 context.codemap.span_after(
224 original_style.opener(),
226 mac.span.hi - BytePos(1),
232 Some(format!("{}{}", macro_name, rewrite))
235 MacroStyle::Braces => {
236 // Skip macro invocations with braces, for now.
242 /// Tries to convert a macro use into a short hand try expression. Returns None
243 /// when the macro is not an instance of try! (or parsing the inner expression
245 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
246 if &format!("{}", mac.node.path)[..] == "try" {
247 let ts: TokenStream = mac.node.tts.clone().into();
248 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
251 id: ast::NodeId::new(0), // dummy value
252 node: ast::ExprKind::Try(try_opt!(parser.parse_expr().ok())),
253 span: mac.span, // incorrect span, but shouldn't matter too much
254 attrs: ThinVec::new(),
261 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> MacroStyle {
262 let snippet = context.snippet(mac.span);
263 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
264 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
265 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
267 if paren_pos < bracket_pos && paren_pos < brace_pos {
269 } else if bracket_pos < brace_pos {