otherzip.jl

generate_zip.jl

module Zipperino
import Base: iterate, tail, @nexprs, @ntuple
using Test, Base.Iterators

struct LinearZip{N,T}
    t::T
end

zip(a...) = LinearZip{length(a),typeof(a)}(a)

@generated function iterate(z::LinearZip{N}) where {N}
    quote
        @nexprs $N j -> begin
            y_j = iterate(z.t[j])
            y_j === nothing && return nothing
        end
        values = @ntuple $N j->y_j[1]
        states = @ntuple $N j->y_j[2]
        values, states
    end
end

@generated function iterate(z::LinearZip{N}, states) where {N}
    quote
        @nexprs $N j -> begin
            y_j = iterate(z.t[j], states[j])
            y_j === nothing && return nothing
        end
        values = @ntuple $N j->y_j[1]
        states = @ntuple $N j->y_j[2]
        values, states
    end
end
end