Using end variable in ranges passed to functions other than getindex?

General Usage
7

I took this too far :smile:: https://github.com/JobJob/EndyIndexes.jl

pkg> add https://github.com/JobJob/EndyIndexes.jl.git

using EndyIndexes

const start_ = StartBasedIdx()
const end_ = EndBasedIdx()

arr = [1:10;]
for idx in (end_-2:end_, start_+1:end_-2)
    @show arr[idx]
end
a = [1,2,3,4,5]
deleteat!(a, end_-1:end_)

Output

arr[idx] = [8, 9, 10]
arr[idx] = [2, 3, 4, 5, 6, 7, 8]
3-element Array{Int64,1}:
 1
 2
 3

Thanks to the fantastic work that went into custom AbstractArray indexing this was surprisingly easy to implement.

Also just re the comment above, in Julia >=0.7, in multi-dimensional index expressions end now lowers to lastindex(a, dim), in single index expressions just to lastindex(a)

jjulia> f1(a) = a[2, end-1:3, 1]
f1 (generic function with 1 method)

julia> f2(a) = a[end]
f2 (generic function with 1 method)

julia> @code_lowered f1(rand(3,3,3))
CodeInfo(
1 1 ─ %1 = (Base.lastindex)(a, 2)                                                                                                                                │
  │   %2 = %1 - 1                                                                                                                                                │
  │   %3 = %2:3                                                                                                                                                  │
  │   %4 = (Base.getindex)(a, 2, %3, 1)                                                                                                                          │
  └──      return %4                                                                                                                                             │
)

julia> @code_lowered f2(rand(3,3,3))
CodeInfo(
1 1 ─ %1 = (Base.lastindex)(a)                                                                                                                                   │
  │   %2 = (Base.getindex)(a, %1)                                                                                                                                │
  └──      return %2                                                                                                                                             │
)