Soo, in summary (and I do apologize for spamming this thread; I don't
usually drink coffee, and when I do it's remarkable):
1) Mauro and Avik seem to be right about the common use case Any[1, 2, 3,
4] lowering to getindex -- my apologies for hastily suggesting otherwise
2) I suspect I was wrong to say that concatenation in general doesn't go
through a function. It probably does, just not always through getindex
(sometimes vcat, typed_vcat, vect, etc).
On Wednesday, June 17, 2015 at 10:15:00 AM UTC-4, David Gold wrote:
>
> However, it does look like this use pattern does resolve to 'getindex',
>
> *julia> **dump(:( Int[1, 2, 3, 4] ))*
>
> Expr
>
> head: Symbol ref
>
> args: Array(Any,(5,))
>
> 1: Symbol Int
>
> 2: Int64 1
>
> 3: Int64 2
>
> 4: Int64 3
>
> 5: Int64 4
>
> typ: Any
>
>
> *julia> **getindex(Int, 1, 2, 3, 4)*
>
> *4-element Array{Int64,1}:*
>
> * 1*
>
> * 2*
>
> * 3*
>
> * 4*
>
>
> So now I am not so sure about my claim that most concatenation doesn't go
> through function calls. However, I don't think that the rest of the
> concatenating heads (:vect, :vcat, :typed_vcat, etc.) lower to getindex:
>
>
> *julia> **@which([1, 2, 3, 4])*
>
> *vect{T}(X::T...) at abstractarray.jl:13*
>
>
> *julia> **@which([1; 2; 3; 4])*
>
> *vcat{T<:Number}(X::T<:Number...) at abstractarray.jl:643*
>
>
> they seem instead to call the type 'vect', 'vcat', etc. itself on the
> array arguments.
>
