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//! An implementation of [this RFC](https://github.com/rust-lang/rfcs/pull/2180). //! //! Provides a single `trait` which allows the construction of an `Option` based on a bool value. //! ``` //! extern crate imply_option; //! //! use imply_option::*; //! //! fn main() { //! let pass = true; //! //! assert_eq!(pass.then(1), Some(1)); //! assert_eq!(pass.then_do(|| 1), Some(1)); //! //! let fail = false; //! //! assert_eq!(fail.then(1), None); //! } //! ``` #![no_std] /// Allows construction of an `Option<T>` based on a `bool`. pub trait ImplyOption<T: Sized>: Sized + PartialEq<bool> { /// If `self == true` returns `Some(value)`. #[inline] fn then(self, value: T) -> Option<T> { self.then_do(move || value) } /// If `self == true` returns `Some(value)` where `value` is lazily constructed. fn then_do(self, value: impl FnOnce() -> T) -> Option<T> { if self == true { Some(value()) } else { None } } } impl<T: Sized + PartialEq<bool>, I: Sized> ImplyOption<I> for T {}