Crate typenum

This crate provides type-level numbers evaluated at compile time.

The traits defined or used in this crate are used in a typical manner. They can be divided into two categories: marker traits and type operators.

Many of the marker traits have functions defined, but they all do essentially the same thing: convert a type into its runtime counterpart, and are really just there for debugging. For example,

assert_eq!(N4::to_i32(), -4);

Type operators* are traits that behave as functions at the type level. These are the meat of this library. Where possible, traits defined in the stdlib have been used, but their attached functions have not been implemented.

For example, the Add trait is implemented for both unsigned and signed integers, but the add function is not. As there are never any objects of the types defined here, it wouldn't make sense to implement it. What is important is its associated type Output, which is where the addition happens.

use std::ops::Add;
use typenum::consts::{P3, P4};
use typenum::int::Integer;

type X = <P3 as Add<P4>>::Output;
assert_eq!(<X as Integer>::to_i32(), 7);

Documented in each module is the full list of type operators implemented.

Modules

bit	Type-level bits. These are rather simple and are used as the building blocks of the other number types in this crate.
consts	This module defines aliases for many constants. It is generated by typenum's build script.
int	Type-level signed integers.
uint	Type-level unsigned integers.

Enums

Equal
Greater
Less

Traits

Cmp	A type operator for comparing Self and Rhs. It provides a similar functionality to the function std::cmp::Ord::cmp but for types.
NonZero	A marker trait to designate that a type is not zero. All number types in this crate implement NonZero except B0, U0, and Z0.
Ord	A Marker trait for the types Greater, Equal, and Less.
Pow	A type operator that provides exponentiation by repeated squaring.
Same	A type operator that ensures that Rhs is the same as Self, it is mainly useful for writing macros that can take arbitrary binary or unary operators.

Type Definitions

Add1	Alias to make it easy to add 1: Add1<A> = <A as Add<B1>>::Output
And	Alias for the associated type of BitAnd: And<A, B> = <A as BitAnd<B>>::Output
Compare	Alias for the associated type of Cmp: Compare<A, B> = <A as Cmp<B>>::Output
Cube	Alias to make it easy to square. Cube<A> = <Square<A> as Mul<A>>::Output
Diff	Alias for the associated type of Sub: Diff<A, B> = <A as Sub<B>>::Output
Exp	Alias for the associated type of Pow: Exp<A, B> = <A as Pow<B>>::Output
Mod	Alias for the associated type of Rem: Mod<A, B> = <A as Rem<B>>::Output
Negate	Alias for the associated type of Neg: Negate<A> = <A as Neg>::Output
Or	Alias for the associated type of BitOr: Or<A, B> = <A as BitOr<B>>::Output
Prod	Alias for the associated type of Mul: Prod<A, B> = <A as Mul<B>>::Output
Quot	Alias for the associated type of Div: Quot<A, B> = <A as Div<B>>::Output
Shleft	Alias for the associated type of Shl: Shleft<A, B> = <A as Shl<B>>::Output
Shright	Alias for the associated type of Shr: Shright<A, B> = <A as Shr<B>>::Output
Square	Alias to make it easy to square. Square<A> = <A as Mul<A>>::Output
Sub1	Alias to make it easy to subtract 1: Sub1<A> = <A as Sub<B1>>::Output
Sum	Alias for the associated type of Add: Sum<A, B> = <A as Add<B>>::Output
Xor	Alias for the associated type of BitXor: Xor<A, B> = <A as BitXor<B>>::Output