Restore Num trait

This restores the trait that was lost in 216e85fadf. It will eventually be broken up into a more fine-grained trait hierarchy in the future once a design can be agreed upon.

src/libcore/core.rc

@@ -99,7 +99,7 @@ pub use vec::{OwnedVector, OwnedCopyableVector};
 pub use iter::{BaseIter, ExtendedIter, EqIter, CopyableIter};
 pub use iter::{CopyableOrderedIter, CopyableNonstrictIter, Times};
 
-pub use num::NumCast;
+pub use num::{Num, NumCast};
 pub use ptr::Ptr;
 pub use to_str::ToStr;
 pub use clone::Clone;

src/libcore/num/num.rs

@@ -16,6 +16,28 @@ use kinds::Copy;
 
 pub mod strconv;
 
+pub trait Num: Eq + Zero + One
+             + Neg<Self>
+             + Add<Self,Self>
+             + Sub<Self,Self>
+             + Mul<Self,Self>
+             + Div<Self,Self>
+             + Modulo<Self,Self> {}
+
+impl Num for u8 {}
+impl Num for u16 {}
+impl Num for u32 {}
+impl Num for u64 {}
+impl Num for uint {}
+impl Num for i8 {}
+impl Num for i16 {}
+impl Num for i32 {}
+impl Num for i64 {}
+impl Num for int {}
+impl Num for f32 {}
+impl Num for f64 {}
+impl Num for float {}
+
 pub trait IntConvertible {
     fn to_int(&self) -> int;
     fn from_int(n: int) -> Self;

src/libcore/prelude.rs

@@ -34,7 +34,7 @@ pub use hash::Hash;
 pub use iter::{BaseIter, ReverseIter, MutableIter, ExtendedIter, EqIter};
 pub use iter::{CopyableIter, CopyableOrderedIter, CopyableNonstrictIter};
 pub use iter::Times;
-pub use num::NumCast;
+pub use num::{Num, NumCast};
 pub use path::GenericPath;
 pub use path::Path;
 pub use path::PosixPath;

src/test/run-pass/trait-inheritance-num.rs

@@ -16,7 +16,7 @@ use core::cmp::{Eq, Ord};
 use core::num::NumCast::from;
 use std::cmp::FuzzyEq;
 
-pub trait NumExt: NumCast + Eq + Ord {}
+pub trait NumExt: Num + NumCast + Eq + Ord {}
 
 pub trait FloatExt: NumExt + FuzzyEq<Self> {}
 

src/test/run-pass/trait-inheritance-num1.rs

@@ -11,7 +11,7 @@
 use core::cmp::Ord;
 use core::num::NumCast::from;
 
-pub trait NumExt: NumCast + Ord { }
+pub trait NumExt: Num + NumCast + Ord { }
 
 fn greater_than_one<T:NumExt>(n: &T) -> bool {
     *n > from(1)

src/test/run-pass/trait-inheritance-num2.rs

@@ -38,7 +38,7 @@ impl TypeExt for f64 {}
 impl TypeExt for float {}
 
 
-pub trait NumExt: TypeExt + Eq + Ord + NumCast {}
+pub trait NumExt: TypeExt + Eq + Ord + Num + NumCast {}
 
 impl NumExt for u8 {}
 impl NumExt for u16 {}

src/test/run-pass/trait-inheritance-num3.rs

@@ -11,7 +11,7 @@
 use core::cmp::{Eq, Ord};
 use core::num::NumCast::from;
 
-pub trait NumExt: Eq + Ord + NumCast {}
+pub trait NumExt: Eq + Ord + Num + NumCast {}
 
 impl NumExt for f32 {}
 

src/test/run-pass/trait-inheritance-num5.rs

@@ -11,7 +11,7 @@
 use core::cmp::{Eq, Ord};
 use core::num::NumCast::from;
 
-pub trait NumExt: Eq + NumCast {}
+pub trait NumExt: Eq + Num + NumCast {}
 
 impl NumExt for f32 {}
 impl NumExt for int {}