using constructor to compute new field

New to Julia
2

“:stuck_out_tongue:” is not a valid type definition :smile: .

Joking aside… This works:

julia> immutable Ray{P<:Point, T<:AbstractFloat}
       v1::P
       v2::P
       dx::T
       dy::T
       dz::T
       function Ray(v1::P, v2::P) where {T,P<:Point{T}}
           dx = v2.x - v1.x
           dy = v2.y - v1.y
           dz = v2.z - v1.z
           dx2 = dx * dx
           dy2 = dy * dy
           dz2 = dz * dz
           s = dx2 + dy2 + dz2
           l = sqrt(s)
           dx = dx / l
           dy = dy / l
           dz = dz / l
           new{P, T}(v1, v2, dx, dy, dz)
       end
       end
julia> p1 = Point(1.0, 2.0, 3.3)
Point{Float64}(1.0, 2.0, 3.3)

julia> p2 = Point(4.0, 3.0, 5.5)
Point{Float64}(4.0, 3.0, 5.5)

julia> r = Ray(p1, p2)
Ray{Point{Float64},Float64}(Point{Float64}(1.0, 2.0, 3.3), Point{Float64}(4.0, 3.0, 5.5), 0.7787611974767475, 0.2595870658255825, 0.5710915448162815)

Also, here is a post explaining how to properly quote your codes here at discourse forum