# VariadicMonoids
This small crate provides (experimental) support for creating variadic functions from monoids.
More simply, given a `fn f(T,T) -> T`, this crate allows you to produce a variadic function `f'` such that
```rust
f'(a: T,b: T, c: T,....) == f(a,f(b,f(c,...f(z,identity)..)))
```
Where Identity is an identity operation on f. (Specifically, only `f(a, identity) == a` must actually hold).
How to Use:
```rust
use variadic_monoids::*;
// You must create a name for your monoid with a struct. This allows you to
// create multiple monoids per type (and they can be for external too)
struct AddMonoid;
impl Monoid<AddMonoid> for i32 {
fn identity() -> Self { 0 }
fn operator(a: Self, b: Self) -> Self { a + b }
}
// Call the (constant function) gen_function to retrieve your function
// With type parameters as the implemented Type, and Name of your monoid.
const sum: VariFunc<i32, AddMonoid> = gen_function::<i32, AddMonoid>();
fn main() {
println!("{}", sum(1,2,3,4));
}
```
In your ```Cargo.toml```
[dependencies]
...
variadic_monoids="0.1.1"