use crate::{Empty, Semigroup};
pub trait Monoid: Empty + Semigroup {}
macro_rules! monoid_numeric_impl {
($($t:ty)*) => ($(
impl Monoid for $t {}
)*)
}
monoid_numeric_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
impl<T: Clone> Monoid for Vec<T> {}
impl Monoid for String {}
#[cfg(test)]
mod laws {
use crate::{Empty, Semigroup};
#[quickcheck]
fn monoid_left_identity(n: i32) {
assert_eq!(i32::empty().combine(n), n)
}
#[quickcheck]
fn monoid_right_identity(n: i32) {
assert_eq!(n.combine(i32::empty()), n)
}
}