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// Copyright 2016 Philipp Matthias Schaefer <philipp.matthias.schaefer@posteo.de> // // 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. //! Execute a block after computing a result. //! //! This crate provides the macro `prog1`, an implementation of the homonymous //! Common Lisp macro. //! //! It allows to compute a result, before executing a block that changes values //! previously used to compute the result. //! //! # Examples //! //! ``` //! #[macro_use] //! extern crate prog1; //! //! fn main() { //! let mut a = 0; //! //! assert_eq!(prog1!(a; { a += 1 }), 0); //! assert_eq!(a, 1); //! } //! ``` /// Executes $after after computing the result $result. /// /// For more information see the crate level documentation. #[macro_export] macro_rules! prog1 { ( $result:expr; $after:block) => {{ let result = $result; $after result }} }