Tried this but no luck. julia> (+!)(x, y) = 0 ERROR: syntax: invalid function name "+(!)" around REPL[35]:1 or julia> function +!(x, y) = 0 end ERROR: syntax: expected "end" in definition of function "+" The idea is to apply it to two custom types and add them in situ. Thanks

I could live with the ugly but the problem is that I would also want -!, *!, /!, ^! ...

That’s easy, you can just overload Base.:-(::A, ::Not), Base.:*(::A, ::Not), etc. Just keep in mind that this only really works if you actually own the type on the right.

Yes, this is to be applied to my own types. Thanks, will try it.

[image] joa-quim: I could live with the ugly but the problem is that I would also want -!, *!, /!, ^! ... If you are trying to define in-place versions of elementary operations like +, presumably because you are working with large data structures and want to avoid heap allocations, then reali…

Well, this something I would like to offer the users of my package. Broadcasting is nice but so would be !functions but I’m not being able to implement it because I can’t see how to access the elements of A & B in above example. I’ll look at the broadcasting too.

BTW, I’m curious about the += operator. Where is it defined?

It’s not a generic operator. a += b is lowered to a = a + b, there’s no way to overload that. If you use the broadcasting machinery like @stevengj suggested, you could intercept a .= ... and therefore also a .+= ... though, through Base.materialize! .

The broadcast machinery looks quite complex, and to start with the type in question does not have an axes as mentioned necessary julia> G1 = mat2grid([0.0 1; 2 3]); julia> axes(G1) ERROR: MethodError: no method matching size(::GMT.GMTgrid)

Perhaps I’m missing something, but your type looks to me like a special matrix type, so is there a reason why you wouldn’t want to define size on it and implement the AbstractArray interface for it?

No, nothing against, only ignorance. But again implementing that interface is not obvious. The Squares example in the docs is too simplistic. Would I have to declare only the type as <: AbstractArray or do I have to do it also for the array members? But I want some of them to remain Float64 only. (…

Is it possible to define a ``+!`` function?

General Usage

stevengj Split this topic September 16, 2020, 8:39pm 21

4 posts were merged into an existing topic: Less than approx equals? <≈

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Is it possible to define a ``+!`` function?

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