Tracking Issue for num_midpoint · Issue #110840 · rust-lang/rust (original) (raw)
Feature gate: #[feature(num_midpoint)], #[feature(num_midpoint_signed)] and #![feature(const_num_midpoint)]
This is a tracking issue for the midpoint function to {u,i}{8,16,32,64,128,size}, NonZeroU{8,16,32,64,size} and f{32,64}.
The midpoint function calculates the middle point of lhs and rhs.
Public API
impl {u,i}{8,16,32,64,128,size} { pub const fn midpoint(self, rhs: Self) -> Self; }
impl NonZeroU{8,16,32,64,size} { pub const fn midpoint(self, rhs: Self) -> Self; }
impl f{32,64} { pub const fn midpoint(self, rhs: Self) -> Self; }
Steps / History
- Implementation: Add midpoint function for all integers and floating numbers #92048
- Final comment period (FCP)1
- For unsigned and floats variants Stabilize unsigned and float variants of num_midpoint feature #131784 (comment)
- For signed variants Stabilize num_midpoint_signed feature #134340
- Stabilization PR
- For unsigned and floats variants Stabilize unsigned and float variants of num_midpoint feature #131784
- For signed variants Stabilize num_midpoint_signed feature #134340
Unresolved Questions
- Rounding of negative signed integer (current behavior is round towards
negative infinityzero): Add midpoint function for all integers and floating numbers #92048 (comment)- As of Round negative signed integer towards zero in iN::midpoint #132191 we round towards zero, as to be consistent with the obvious impl
(a + b) / 2.
- As of Round negative signed integer towards zero in iN::midpoint #132191 we round towards zero, as to be consistent with the obvious impl
Whether it's commutative (some people wantmidpoint(a, b) == midpoint(b, a), but others want a non-commutative definition)- The (unsigned) FCP proposed that it be commutative and that was accepted.