diff options
Diffstat (limited to 'src/libstd')
| -rw-r--r-- | src/libstd/cmp.rs | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/src/libstd/cmp.rs b/src/libstd/cmp.rs index 2c4bb46b23b..77d4e945aae 100644 --- a/src/libstd/cmp.rs +++ b/src/libstd/cmp.rs @@ -157,19 +157,20 @@ pub fn lexical_ordering(o1: Ordering, o2: Ordering) -> Ordering { /** * Trait for values that can be compared for a sort-order. * -* Eventually this may be simplified to only require -* an `le` method, with the others generated from -* default implementations. However it should remain -* possible to implement the others separately, for -* compatibility with floating-point NaN semantics +* Ord only requires implementation of the `lt` method, +* with the others generated from default implementations. +* +* However it remains possible to implement the others separately, +* for compatibility with floating-point NaN semantics * (cf. IEEE 754-2008 section 5.11). */ +#[allow(default_methods)] // NOTE: Remove when allowed in stage0 #[lang="ord"] pub trait Ord { fn lt(&self, other: &Self) -> bool; - fn le(&self, other: &Self) -> bool; - fn ge(&self, other: &Self) -> bool; - fn gt(&self, other: &Self) -> bool; + fn le(&self, other: &Self) -> bool { !other.lt(self) } + fn gt(&self, other: &Self) -> bool { other.lt(self) } + fn ge(&self, other: &Self) -> bool { !self.lt(other) } } /// The equivalence relation. Two values may be equivalent even if they are |