use std::cmp::PartialEq;
use std::num::{Zero, One};
use std::ops::{Add, Sub, Mul, Div, Rem};


/// A trait that defines what is required to be considered
/// a number.
pub trait Number : Zero + One + Add<Output=Self> + Sub<Output=Self> +
                   Mul<Output=Self> + Div<Output=Self> + Rem<Output=Self> +
                   PartialEq + Copy + Clone
{
   type StrRadixError;

   /// Create a number from a given string and base radix.
   fn from_str_radix(src: &str, radix: u32) ->
      Result<Self, Self::StrRadixError>;
}


// Create some macros to ease typing and reading.
/// A macro to make implementing the trait easier for all the
/// base integer types in rust.
macro_rules! int_trait_impl
{
   ($traitName: ident for $($varType: ty)*) =>
      ($(
         impl Number for $varType
         {
            type StrRadixError = ::std::num::ParseIntError;

            fn from_str_radix(src: &str, radix: u32) ->
               Result<Self, ::std::num::ParseIntError>
            {
               <$varType>::from_str_radix(src, radix)
            }
         }
      )*)
}

/// A macro to make implementing the trait easier for all the
/// base float types in rust.
macro_rules! float_trait_impl
{
   ($traitName: ident for $($varType: ty)*) =>
   ($(
      impl $traitName for $varType
      {
         type StrRadixError = ::std::num::ParseFloatError;

         fn from_str_radix(src: &str, radix: u32) ->
            Result<Self, ::std::num::ParseFloatError>
         {
            <$varType>::from_str_radix(src, radix)
         }
      }
   )*)
}


// Implement the trait for the types that are Numbers.
int_trait_impl!(Number for u8 u16 u32 u64 usize);
int_trait_impl!(Number for i8 i16 i32 i64 isize);
float_trait_impl!(Number for f32 f64);