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#![no_std]
#![deny(
missing_docs,
missing_debug_implementations,
missing_copy_implementations,
trivial_casts,
trivial_numeric_casts,
unsafe_code,
unstable_features,
unused_import_braces,
unused_qualifications
)]
//! Tailcall is a library that adds safe, zero-cost [tail recursion] to stable Rust.
//! Eventually, it will be superseded by the [`become` keyword].
//!
//! # Usage
//!
//! To guarantee that recursive calls a function will reuse the same stack frame,
//! annotate it with the [`tailcall`] attribute.
//!
//! ```
//! use tailcall::tailcall;
//!
//! fn factorial(input: u64) -> u64 {
//! #[tailcall]
//! fn factorial_inner(accumulator: u64, input: u64) -> u64 {
//! if input > 0 {
//! factorial_inner(accumulator * input, input - 1)
//! } else {
//! accumulator
//! }
//! }
//!
//! factorial_inner(1, input)
//! }
//! ```
//!
//! Recursive calls which are not in tail form will result in a compile-time error.
//!
//! ```compile_fail
//! use tailcall::tailcall;
//!
//! #[tailcall]
//! fn factorial(input: u64) -> u64 {
//! if input > 0 {
//! input * factorial(input - 1)
//! } else {
//! 1
//! }
//! }
//! ```
//!
//! [tail recursion]: https://en.wikipedia.org/wiki/Tail_call
//! [`become` keyword]: https://internals.rust-lang.org/t/pre-rfc-explicit-proper-tail-calls/3797/16
//! [`tailcall`]: attr.tailcall.html
pub use tailcall_impl::tailcall;
pub mod trampoline;