I heard a rumour that Julia’s multiple dispatch is “fake news”, in reality it’s overloading because you compile the function before it is run and all you are doing in Julia is just a series of compile and run actions. Is this true? Thanks in advance.

I apologize ahead of time for resurrecting an old thread here, but I think a brief summary of this discussion might be helpful for posterity. There is a lot of confusion in this thread over semantics and definitions, which likely makes it rather time consuming and difficult to read for newcomers and…

I would also nominate this answer by @StefanKarpinski which touched on a lot of the same points that I raised in my summary.

Best if @dataSurfer would do this.

It may be a good idea to add the answer to the FAQ of Julia’s manual, given that Julia cites multiple dispatch as a main feature. I was also confused by this for a long time.

I marked yours as the answer because I think it’s a better overview of the whole discussion and it refers to mine so people can find it that way if they want more detail.

[image] bgroenks: However, this is still not enough. In order to accomplish similar behavior with static overloading, we would need concrete overloads for each special type, e.g: ols(x::AbstractVector{T}, y::AbstractVector{T}) where {T} = ... ols(x::AbstractMatrix{T}, y::AbstractVector{T}) wher…

I did not say that it was not possible to achieve this in other ways in C++. I said it was prohibitively difficult to do it with overloading alone. Of course one could certainly use generic programming (in C++, templates) to accomplish something similar, although this comes with a whole range of iss…

I am just curious. How would you call that something similar? Is it overloading or not? Is it multiple dispatch or not? And why?

[image] Liso: How would you call that something similar ? Is it overloading or not? Is it multiple dispatch or not? clearly you could achieve static overloading with static overloading alone, it’s the late binding that is hard to achieve: [image] bgroenks: with static overloading As…

No, templates and generic types are not multiple dispatch. However, they can be seen as a static type solution to one of the problems I described, namely the redundancy of defining functions for multiple types. As @jling pointed out, C++ templates are pretty much literally just syntactic sugar for …

Saying just syntactic sugar is … questionable. You could similarly say that higher level programmer language is just syntactic sugar for assembler or machine code. You say that “true” dispatch need to be polymorphic. But … : [image] StefanKarpinski: However, that disagrees with what people i…

Claim (false): Julia isn't multiple dispatch but overloading

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Claim (false): Julia isn't multiple dispatch but overloading

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