FYI: other package and speed

[PallHaraldsson]

Good to know about that fastest option you mention (and ArgMacros you do not, but might want to).

Speed is not everything, but yours is slowest, at least at starting, not sure when you add useful work:

julia> @time using DocOpt
  0.012110 seconds (14.44 k allocations: 836.352 KiB)

julia> @time using ArgParse
  0.043875 seconds (43.98 k allocations: 3.469 MiB)

julia> @time using ArgMacros
  0.046656 seconds (37.61 k allocations: 3.137 MiB)


julia> @time using ArgParse2
  0.172533 seconds (87.85 k allocations: 5.838 MiB)

julia> @time using ArgParse2
  0.000889 seconds (255 allocations: 13.984 KiB)

julia> @time using ArgParse2
  0.000292 seconds (120 allocations: 8.156 KiB)

As you can see the second using has more allocations (and not as fast) as the third, a hint to invalidation (unlike e.g. for ArgMacros), that I understand slow down startup (first using), and SnoopCompile.jl can help.

I'm not too concerned in your case, it's just that with (other) packages slow, I'm looking into such issues, and don't want people do avoid Julia for scripting.