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// file: types.rs
//
// Copyright 2015-2017 The RsGenetic Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! This module provides implementations of the `Fitness` trait for
//! some primitive types, such as `i32`, `i64` etcetera.
//! This is because Rust does not allow programmers to implement
//! a foreign trait for a foreign type, which would stop you as a library user
//! from using primitive types as fitness values.
//!
//! Implemented types:
//!
//! * `i8`
//! * `i16`
//! * `i32`
//! * `i64`
//! * `u8`
//! * `u16`
//! * `u32`
//! * `u64`
//! * `usize`

use pheno::Fitness;

macro_rules! implement_fitness_int {
    ( $($t:ty),* ) => {
        $(
            impl Fitness for $t {
                fn zero() -> $t {
                    0
                }
    
                fn abs_diff(&self, other: &$t) -> $t {
                    if self > other {
                        self - other
                    } else {
                        other - self
                    }
                }
            }
        )*
    }
}

implement_fitness_int!(i8, i16, i32, i64, u8, u16, u32, u64, usize);