If I understand correctly, you want to pass an instance of Foo into fun2,
which would then effectively call "fun1(Foo, Foo())". I don't quite
understand the use case... can you give an example of when the second
"fun1" definition would be called?
On Friday, May 1, 2015 at 9:24:59 AM UTC-4, Tamas Papp wrote:
>
> Not really --- I wanted to dispatch on something being an _instance_ of
> a type that is a DataType. Having reread the manual, I don't think that
> is possible directly, but works with one level of indirection:
>
> fun1(T::DataType,x) = "do something with $x"
> fun1(T, x) = "this is not a datatype"
> fun2{T}(x::T) = fun1(T,x)
> type Foo end
> fun2(Foo())
>
> That said, I realized that DataType is not what I need.
>
> Best,
>
> Tamas
>
> On Thu, Apr 30 2015, Tom Breloff <[email protected] <javascript:>> wrote:
>
> > 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
> >>
>
