I found this approach in Rotations.jl. Why code it this way? Note that AngleAxis is a concrete type, so AA can only be one type. @inline function (::Type{AA})(q::QuatRotation) where AA <: AngleAxis w = real(q.q) x, y, z = imag_part(q.q) s2 = x * x + y * y + z * z sin_t2 = sqrt(s2) …

No the signatures look the same AFAICT. These aren’t really callable structs. It is a strange way to write a constructor, but I can’t seem to find a difference. This can be used to do certain “Abstract” constructors but AngleAxis is a struct so I’m not sure the purpose.

Are these type functors the same as Outer Constructors?

General Usage

Oscar_Smith February 22, 2024, 6:53pm 2

No. These are callable structs (see Function factories or callable structs?)

Topic		Replies	Views
Parametric Outer Constructor General Usage	3	1055	February 16, 2019
Type() vs type() -- Are constructor methods or conversion functions more idiomatic? General Usage constructors , multiple-dispatch	4	417	January 20, 2023
Difference between two forms of inner constructors General Usage	10	1594	July 13, 2017
Can this be done with an outer constructor? New to Julia	2	444	May 22, 2020
Defining an outer constructor leads to infinite recursion New to Julia question	15	245	November 2, 2024

Are these type functors the same as Outer Constructors?

Related topics