| // Copyright 2012 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // This test has some extra semis in it that the pretty-printer won't |
| // reproduce so we don't want to automatically reformat it |
| |
| // no-reformat |
| |
| |
| /* |
| * |
| * When you write a block-expression thing followed by |
| * a lone unary operator, you can get a surprising parse: |
| * |
| * if (...) { ... } |
| * -num; |
| * |
| * for example, or: |
| * |
| * if (...) { ... } |
| * *box; |
| * |
| * These will parse as subtraction and multiplication binops. |
| * To get them to parse "the way you want" you need to brace |
| * the leading unops: |
| |
| * if (...) { ... } |
| * {-num}; |
| * |
| * or alternatively, semi-separate them: |
| * |
| * if (...) { ... }; |
| * -num; |
| * |
| * This seems a little wonky, but the alternative is to lower |
| * precedence of such block-like exprs to the point where |
| * you have to parenthesize them to get them to occur in the |
| * RHS of a binop. For example, you'd have to write: |
| * |
| * 12 + (if (foo) { 13 } else { 14 }); |
| * |
| * rather than: |
| * |
| * 12 + if (foo) { 13 } else { 14 }; |
| * |
| * Since we want to maintain the ability to write the latter, |
| * we leave the parens-burden on the trailing unop case. |
| * |
| */ |
| |
| pub fn main() { |
| |
| let num = 12; |
| |
| assert_eq!(if (true) { 12 } else { 12 } - num, 0); |
| assert_eq!(12 - if (true) { 12 } else { 12 }, 0); |
| if (true) { 12; } {-num}; |
| if (true) { 12; }; {-num}; |
| if (true) { 12; };;; -num; |
| } |