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//! This crate provides a generic pointer-like [`Lazy<T, Eval>`](struct.Lazy.html) struct for lazily initialized values.
//! It can be used for expensive-to-calculate values to ensure that the evaluation logic runs
//! only once and only if needed.
//! 
//! For example:
//! ```
//! use sloth::Lazy;
//! 
//! fn get_expensive_string() -> String {
//!     // do something expensive here to obtain the result,
//!     // such as read and process file contents
//!     String::from("some expensive string we got from a file or something")
//! }
//! 
//! fn get_expensive_number() -> i32 {
//!     // do something expensive here to calculate the result,
//!     // such as build a supercomputer and wait 7.5 million years
//!     42
//! }
//! 
//! let lazy_string = Lazy::new(get_expensive_string);
//! let lazy_number = Lazy::new(get_expensive_number);
//! 
//! //...
//! let must_use_string = true;
//! //...
//! 
//! if must_use_string {
//!     println!("Expensive string is: {}", *lazy_string);
//!     println!("It has length: {}", lazy_string.len());
//!
//!     // get_expensive_string() has been called only once,
//!     // get_expensive_number() has not been called
//! } else {
//!     println!("Expensive number is: {}", *lazy_number);
//!     println!("Its square is {}", lazy_number.pow(2));
//! 
//!     // get_expensive_string() has not been called,
//!     // get_expensive_number() has been called only once
//! }
//! 
//! ```
//! 
//! The evaluated value of a mutable [`Lazy`](struct.Lazy.html) can be modified:
//! ```
//! use sloth::Lazy;
//! 
//! let mut lazy_vec = Lazy::new(|| vec![2, -5, 6, 0]);
//! 
//! lazy_vec.retain(|n| *n > 0);
//! 
//! assert_eq!(*lazy_vec, vec![2, 6]);
//! ```
//! 
//! [`Lazy`](struct.Lazy.html) can be consumed and turned into its value via [`unwrap()`](struct.Lazy.html#method.unwrap):
//! ```
//! use sloth::Lazy;
//! 
//! let lazy_value = Lazy::new(|| "moo");
//! 
//! let output = String::from("a cow goes ") + lazy_value.unwrap();
//! ```

//
// Modules
//

mod lazy;

// Unit tests
#[cfg(test)]
#[allow(deprecated)]
mod tests;

//
// Exports
//

pub use lazy::Lazy;