From 4d7d101a76deea69e9078d9ed6bb93ecca70e52a Mon Sep 17 00:00:00 2001 From: Daniel Micay Date: Mon, 24 Feb 2014 08:11:00 -0500 Subject: create a sensible comparison trait hierarchy * `Ord` inherits from `Eq` * `TotalOrd` inherits from `TotalEq` * `TotalOrd` inherits from `Ord` * `TotalEq` inherits from `Eq` This is a partial implementation of #12517. --- src/libstd/cmp.rs | 14 ++++++++------ src/libstd/iter.rs | 16 +++++++++++----- src/libstd/option.rs | 2 +- src/libstd/vec.rs | 4 ++-- src/libstd/vec_ng.rs | 15 +++++++++++---- 5 files changed, 33 insertions(+), 18 deletions(-) (limited to 'src/libstd') diff --git a/src/libstd/cmp.rs b/src/libstd/cmp.rs index 291f1dd04d3..6975c9da3f0 100644 --- a/src/libstd/cmp.rs +++ b/src/libstd/cmp.rs @@ -42,8 +42,12 @@ pub trait Eq { } /// Trait for equality comparisons where `a == b` and `a != b` are strict inverses. -pub trait TotalEq { - fn equals(&self, other: &Self) -> bool; +pub trait TotalEq: Eq { + /// This method must return the same value as `eq`. It exists to prevent + /// deriving `TotalEq` from fields not implementing the `TotalEq` trait. + fn equals(&self, other: &Self) -> bool { + self.eq(other) + } } macro_rules! totaleq_impl( @@ -76,7 +80,7 @@ totaleq_impl!(char) pub enum Ordering { Less = -1, Equal = 0, Greater = 1 } /// Trait for types that form a total order -pub trait TotalOrd: TotalEq { +pub trait TotalOrd: TotalEq + Ord { fn cmp(&self, other: &Self) -> Ordering; } @@ -161,7 +165,7 @@ pub fn lexical_ordering(o1: Ordering, o2: Ordering) -> Ordering { * (cf. IEEE 754-2008 section 5.11). */ #[lang="ord"] -pub trait Ord { +pub trait Ord: Eq { fn lt(&self, other: &Self) -> bool; #[inline] fn le(&self, other: &Self) -> bool { !other.lt(self) } @@ -169,8 +173,6 @@ pub trait Ord { fn gt(&self, other: &Self) -> bool { other.lt(self) } #[inline] fn ge(&self, other: &Self) -> bool { !self.lt(other) } - - // FIXME (#12068): Add min/max/clamp default methods } /// The equivalence relation. Two values may be equivalent even if they are diff --git a/src/libstd/iter.rs b/src/libstd/iter.rs index a01a4bf3d62..6bf3cdf52ab 100644 --- a/src/libstd/iter.rs +++ b/src/libstd/iter.rs @@ -2033,7 +2033,7 @@ pub fn range_inclusive + Ord + Clone + One + ToPrimitive>(start: A, RangeInclusive{range: range(start, stop), done: false} } -impl + Eq + Ord + Clone + ToPrimitive> Iterator for RangeInclusive { +impl + Ord + Clone + ToPrimitive> Iterator for RangeInclusive { #[inline] fn next(&mut self) -> Option { match self.range.next() { @@ -2244,7 +2244,7 @@ pub mod order { } /// Return `a` < `b` lexicographically (Using partial order, `Ord`) - pub fn lt>(mut a: T, mut b: T) -> bool { + pub fn lt>(mut a: T, mut b: T) -> bool { loop { match (a.next(), b.next()) { (None, None) => return false, @@ -2256,7 +2256,7 @@ pub mod order { } /// Return `a` <= `b` lexicographically (Using partial order, `Ord`) - pub fn le>(mut a: T, mut b: T) -> bool { + pub fn le>(mut a: T, mut b: T) -> bool { loop { match (a.next(), b.next()) { (None, None) => return true, @@ -2268,7 +2268,7 @@ pub mod order { } /// Return `a` > `b` lexicographically (Using partial order, `Ord`) - pub fn gt>(mut a: T, mut b: T) -> bool { + pub fn gt>(mut a: T, mut b: T) -> bool { loop { match (a.next(), b.next()) { (None, None) => return false, @@ -2280,7 +2280,7 @@ pub mod order { } /// Return `a` >= `b` lexicographically (Using partial order, `Ord`) - pub fn ge>(mut a: T, mut b: T) -> bool { + pub fn ge>(mut a: T, mut b: T) -> bool { loop { match (a.next(), b.next()) { (None, None) => return true, @@ -2978,6 +2978,12 @@ mod tests { } } + impl Eq for Foo { + fn eq(&self, _: &Foo) -> bool { + true + } + } + impl Ord for Foo { fn lt(&self, _: &Foo) -> bool { false diff --git a/src/libstd/option.rs b/src/libstd/option.rs index 633d6e92c70..7997c5747b4 100644 --- a/src/libstd/option.rs +++ b/src/libstd/option.rs @@ -40,7 +40,7 @@ use any::Any; use clone::Clone; use clone::DeepClone; -use cmp::{Eq, TotalEq, TotalOrd}; +use cmp::{Eq, TotalOrd}; use default::Default; use iter::{Iterator, DoubleEndedIterator, FromIterator, ExactSize}; use kinds::Send; diff --git a/src/libstd/vec.rs b/src/libstd/vec.rs index 59136c99ec9..69bf5f5d0fc 100644 --- a/src/libstd/vec.rs +++ b/src/libstd/vec.rs @@ -682,7 +682,7 @@ pub mod traits { fn cmp(&self, other: &~[T]) -> Ordering { self.as_slice().cmp(&other.as_slice()) } } - impl<'a, T: Eq + Ord> Ord for &'a [T] { + impl<'a, T: Ord> Ord for &'a [T] { fn lt(&self, other: & &'a [T]) -> bool { order::lt(self.iter(), other.iter()) } @@ -700,7 +700,7 @@ pub mod traits { } } - impl Ord for ~[T] { + impl Ord for ~[T] { #[inline] fn lt(&self, other: &~[T]) -> bool { self.as_slice() < other.as_slice() } #[inline] diff --git a/src/libstd/vec_ng.rs b/src/libstd/vec_ng.rs index 0a5a7c2da47..ae918bfa98b 100644 --- a/src/libstd/vec_ng.rs +++ b/src/libstd/vec_ng.rs @@ -13,7 +13,7 @@ use cast::{forget, transmute}; use clone::Clone; -use cmp::{Eq, Ordering, TotalEq, TotalOrd}; +use cmp::{Ord, Eq, Ordering, TotalEq, TotalOrd}; use container::Container; use default::Default; use fmt; @@ -136,21 +136,28 @@ impl Extendable for Vec { } } -impl Eq for Vec { +impl Eq for Vec { #[inline] fn eq(&self, other: &Vec) -> bool { self.as_slice() == other.as_slice() } } -impl TotalEq for Vec { +impl Ord for Vec { + #[inline] + fn lt(&self, other: &Vec) -> bool { + self.as_slice() < other.as_slice() + } +} + +impl TotalEq for Vec { #[inline] fn equals(&self, other: &Vec) -> bool { self.as_slice().equals(&other.as_slice()) } } -impl TotalOrd for Vec { +impl TotalOrd for Vec { #[inline] fn cmp(&self, other: &Vec) -> Ordering { self.as_slice().cmp(&other.as_slice()) -- cgit 1.4.1-3-g733a5