Is this what you're looking for?
julia> yyy(x::DataType) = true
yyy (generic function with 1 method)
julia> yyy(x) = false
yyy (generic function with 2 methods)
julia> yyy(Int)
true
julia> yyy(5)
false
On Thursday, April 30, 2015 at 11:04:02 AM UTC-4, Tamas Papp wrote:
>
> This is toy problem that came up in the context of something larger,
> reduced to be simple so that I can ask about it more easily.
>
> Suppose I want to implement the function
>
> is_instanceof_datatype(x) = is(typeof(x),DataType)
>
> using dispatch: a default method that is
>
> is_instanceof_datatype(x) = false
>
> and some other method which only gets called when x is an instance of a
> DataType:
>
> is_instanceof_datatype{ ... }(x::T) = true # how to dispatch
>
> but I don't know how to do the latter, hence the ....
>
> The context is that I want to write a method that, for instances of
> DataTypes, returns the slots in a given order, but for other values it
> does something else, and I don't know how to do this.
>
> Best,
>
> Tamas
>
