argmin/argmax not defined for Tuples and maybe others

[anowacki]

Although argmin/argmax on v0.7+ are defined on anything you can iterate (via findmin/findmax), that's not the case within Compat at the moment. Currently, they are defined for:

1. AbstractArray
2. AbstractVector
3. Associative

Therefore, you can't currently write compatible code if you want to use Tuples:

julia> VERSION
v"0.6.3"

julia> using Compat

julia> argmin((1, 2, 3.0))
ERROR: MethodError: no method matching argmin(::Tuple{Int64,Int64,Int64})
Closest candidates are:
  argmin(::AbstractArray{T,1} where T) at /Users/nowacki/.julia/v0.6/Compat/src/Compat.jl:1401
  argmin(::AbstractArray) at /Users/nowacki/.julia/v0.6/Compat/src/Compat.jl:1400
  argmin(::Associative) at /Users/nowacki/.julia/v0.6/Compat/src/Compat.jl:1402

Works fine with indmin/indmax, of course:

julia> indmin((1, 2, 3.0))
1

[anowacki]

Potential remedy at #622. It's possible there may be types for which this should not be defined, but for argmin/argmax in Base in v0.7+ Any is accepted, so I think it should be okay.

[martinholters]

This is only fixed for the Tuple part, not for the "and maybe others", because there is not necessarily a generally valid way to implement this in 0.6. But we can re-open this issue or open another one if the need for a specific "other" one arises.