This is something I thought a lot about recently. Basically, I want to have the exact functionality of a concrete type and be able to call all function that takes the type but I also want to be able to dispatch differently if I want. And I don't want to manually have to copy all the methods.
In summary, dispatch on typealias. I see this has been discussed before: https://groups.google.com/forum/#!msg/julia-dev/v8B1tI_NB5E/tk98D0iKopYJ https://github.com/JuliaLang/julia/pull/3292 I realize this is basically subtyping from a concrete type which seems to be a big nono but there would be so much nice things you could do with this. On Tuesday, March 17, 2015 at 11:02:17 AM UTC+1, Mauro wrote: > > > My thinking being that this would help avoid ambiguity with my code, as > I > > sometimes work with other units of time (e.g. seconds) that are also > > floating point numbers. Of course, this introduced a number of problems > in > > my existing code, including > > There is also the Units.jl package, which may be of use? > > > 1. Arithmetic operators not defined for type JDate. My workaround for > > this has thus far been to overload the operators to accept JDate > types. > > 2. My functions not having methods that accept time as a JDate type. > My > > workaround for this has been to change the function to accept > time::FloatingPoint > > instead of time::Float64, but this workaround does not work for > Arrays. > > This is a only partially solved problem, as far as I know. How do I > wrap a datatype without having to re-implement all its methods. > Sometimes this can be done through subtyping, but not always. > > One approach is to use a macro to delegate methods to one of the fields > of the datatype: > > https://github.com/JuliaLang/DataStructures.jl/search?utf8=%E2%9C%93&q=delegate > > https://github.com/JuliaLang/julia/pull/3292 > > For relatively simple number types, as in your case here, it might be > better to manually hook into the "conversion and promotion" framework of > Julia: > http://docs.julialang.org/en/latest/manual/conversion-and-promotion/ >
