Combining functors, broadcasting, and pipes

General Usage
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2

I think the infix syntax is a bit of a distraction here. If you define a new function:

julia> function pipe(x, f)
         x |> f
       end
pipe (generic function with 1 method)

then I hope you’ll agree that:

(3, 4) .|> ms1

should be equivalent to:

pipe.((3, 4), ms1)

When written without the |> infix, I think it becomes more obvious why this doesn’t work: you are broadcasting over both the input (3, 4) and your struct ms1 itself. Julia doesn’t know how to iterate over a MyStruct, so this broadcast fails.

Wrapping ms1 in a 1-element tuple fixes the issue because you are now broadcasting over that tuple, which works just fine. Ref(ms1) would also work, and is a bit more idiomatic in Julia.

You can tell Julia to treat your struct as a scalar in broadcasting operations with:

Base.broadcastable(s::MyStruct) = Ref(s)

at which point all of your examples should now work as intended:

julia> (3,4) .|> ms1
(6, 8)
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