I think an even better definition would be
julia> type SelfRef
objs::Array{SelfRef,1}
function SelfRef()
x = new()
x.objs = SelfRef[]
return x
end
end
julia> x=SelfRef()
SelfRef([])
julia> push!(x.objs,SelfRef())
1-element Array{SelfRef,1}:
SelfRef([])
julia> x
SelfRef([SelfRef([])])
That way the first element of objs doesn't loop back around to itself.
On Wednesday, June 18, 2014 2:08:15 PM UTC-7, Stefan Karpinski wrote:
>
> Right, this definition is better:
>
> julia> type SelfRef
> objs::Array{SelfRef,1}
> function SelfRef()
> x = new()
> x.objs = [x]
> return x
> end
> end
>
> julia> x = SelfRef()
> SelfRef([SelfRef(#= circular reference =#)])
>
>
> We don't enforce that constructors actually return the appropriate type.
>
>
> On Wed, Jun 18, 2014 at 4:58 PM, Luke Stagner <[email protected]
> <javascript:>> wrote:
>
>> Thanks Stefan, although I feel like
>> julia> x = SelfRef()
>> 1-element Array{SelfRef,1}:
>> SelfRef([SelfRef(#= circular reference =#)])
>>
>> Should not return an array of type SelfRef. It should return just an
>> instance of itself
>> As it stands, to get the behavior I want I need to call it like
>> julia> x=SelfRef()[1]
>> SelfRef([SelfRef(#= circular reference =#)])
>>
>> julia> x.objs
>> 1-element Array{SelfRef,1}:
>> SelfRef([SelfRef(#= circular reference =#)])
>>
>> julia> push!(x.objs,SelfRef()[1])
>> 2-element Array{SelfRef,1}:
>> SelfRef([SelfRef(#= circular reference =#),SelfRef([SelfRef(#= circular
>> reference =#)])])
>> SelfRef([SelfRef(#= circular reference =#)])
>>
>>
>> On Wednesday, June 18, 2014 12:24:34 PM UTC-7, Stefan Karpinski wrote:
>>
>>> This works:
>>>
>>> julia> type SelfRef
>>> objs::Array{SelfRef,1}
>>> function SelfRef()
>>> x = new()
>>> x.objs = [x]
>>> end
>>> end
>>>
>>> julia> x = SelfRef()
>>> 1-element Array{SelfRef,1}:
>>> SelfRef([SelfRef(#= circular reference =#)])
>>>
>>>
>>> A couple of points:
>>>
>>> The type Array{SelfRef,0} is a zero-dimensional array of SelfRef
>>> objects, not a zero-length one-dimensional array of SelfRef objects. The
>>> type of a one-dimensional array of SelfRef objects is Array{SelfRef,1} –
>>> aka Vector{SelfRef}.
>>>
>>> The first argument to the Array constructor is always a type, whereas x
>>> is an instance of type SelfRef. Writing [x] gives a vector of type SelfRef
>>> containing just x.
>>>
>>>
>>>
>>> On Wed, Jun 18, 2014 at 4:32 AM, Luke Stagner <[email protected]>
>>> wrote:
>>>
>>>> Hello all,
>>>>
>>>> I know it is possible to have a self-referential type like the following
>>>>
>>>> type SelfRef
>>>> obj::SelfRef
>>>> SelfRef() = (x=new(); x.obj=x)
>>>> end
>>>>
>>>> what I want to do is have obj be an array of type SelfRef so I can make
>>>> a tree-like structure. I tried the following
>>>>
>>>> type SelfRef
>>>> obj::Array{SelfRef,0}
>>>> SelfRef() = (x=new(); x.obj=Array(x,0))
>>>> end
>>>>
>>>> but that throws the following error (on nightly)
>>>> julia> a=SelfRef()
>>>> ERROR: no method Array{T,N}(SelfRef)
>>>> in SelfRef at none:3
>>>>
>>>> Is there anyway I can make this work?
>>>>
>>>
>>>
>
