32 lines
947 B
Rust
32 lines
947 B
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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macro_rules! higher_order {
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(subst $lhs:tt => $rhs:tt) => ({
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macro_rules! anon { $lhs => $rhs }
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anon!(1_usize, 2_usize, "foo")
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});
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}
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macro_rules! outer {
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($x:expr; $fragment:ident) => {
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macro_rules! inner { ($y:$fragment) => { $x + $y } }
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}
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}
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fn main() {
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let val = higher_order!(subst ($x:expr, $y:expr, $foo:expr) => (($x + $y, $foo)));
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assert_eq!(val, (3, "foo"));
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outer!(2; expr);
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assert_eq!(inner!(3), 5);
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}
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