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 infinity zero): 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.
• Whether it's commutative (some people want midpoint(a, b) == midpoint(b, a), but others want a non-commutative definition)
  • The (unsigned) FCP proposed that it be commutative and that was accepted.