fieldnames extension of Parameter Struct

[stevengogogo]

Dear Developers,

I'm wondering that whether Base. fieldnames (or something similar) can be used to list all the fieldnames of the stuct of Parameter.jl.

The following is the command that I tried to get all the field names from the Base function

julia> using Parameters

julia> @with_kw struct foo
           a 
       end
foo

julia> f = foo(1)
foo
  a: Int64 1

julia> fieldnames(f)
ERROR: MethodError: no method matching fieldnames(::foo)
Closest candidates are:
  fieldnames(::Core.TypeofBottom) at reflection.jl:175
  fieldnames(::Type{var"#s9"} where var"#s9"<:Tuple) at reflection.jl:177
  fieldnames(::DataType) at reflection.jl:172
  ...
Stacktrace:
 [1] top-level scope at REPL[4]:1

julia> 

Probably using extension to make parameter.jl fit to Base.fieldnames is an option.

Something like

function Base.fieldnames(foo::StructofParameters)
    # To Do
end

[stevengogogo]

I found this works

julia> using Parameters

julia> @with_kw struct foo
                  a 
              end
foo

julia> fieldnames(foo)
(:a,)