OK, I've gotten by this by doing:
*B{AbstractA}()*
... but it would be neat if I could just infer that type in the inner
constructor.
On Friday, January 1, 2016 at 5:06:33 PM UTC-5, Christopher Alexander wrote:
>
> Thanks! I'm having a bit of trouble with that setup when the type is
> parameterized, as below:
>
>
>
>
> *abstract AbstractAtype A <: AbstractA endtype B{T <: AbstractA} a::T
> B() = new()end*
>
> I am getting this error:
>
> *ERROR: MethodError: `convert` has no method matching
> convert(::Type{B{T<:AbstractA}})*
>
> *This may have arisen from a call to the constructor B{T<:AbstractA}(...),*
>
> *since type constructors fall back to convert methods.*
>
> Closest candidates are:
>
> convert{T}(::Type{T}, *::T*)
>
> call{T}(::Type{T}, *::Any*)
>
> in call at essentials.jl:57
>
> Is that the proper way to set that up?
>
> Thanks!!
>
> Chris
>
> On Friday, January 1, 2016 at 4:45:12 PM UTC-5, Tim Holy wrote:
>>
>> If you make `ts` the last parameter, using an inner constructor you can
>> leave
>> that field undefined when you initially create the object, then fill it
>> in later.
>> You may need to sprinkle some `isdefined(b, :ts)` in various places in
>> your
>> code.
>>
>> Happy New Year!
>> --Tim
>>
>> On Friday, January 01, 2016 11:01:02 AM Christopher Alexander wrote:
>> > I'm actually having a slight problem with this implementation.
>> Basically,
>> > in using the parametric approach above, when I initially create an
>> instance
>> > of the Bond type with the NullTermStructure and then set its term
>> structure
>> > with the new TermStructure instance that I create (creating the
>> circular
>> > reference), I get a convert error. I'm assuming this is because the
>> > initial instantiation of the Bond wants a TermStructure of type
>> > NullTermStructure, so then when I try to re-set it with
>> PiecewiseYieldCurve,
>> > it complains. Is there any way to avoid setting it with the
>> > NullTermStructure in the first place?
>> >
>> > Thanks!
>> >
>> > Chris
>> >
>> > On Friday, January 1, 2016 at 1:24:21 PM UTC-5, Christopher Alexander
>> wrote:
>> > > Thanks Tim, this is very helpful! Happy New Year!
>> > >
>> > > - Chris
>> > >
>> > > On Thursday, December 31, 2015 at 6:33:29 PM UTC-5, Tim Holy wrote:
>> > >> See
>> > >>
>> http://docs.julialang.org/en/stable/manual/faq/#how-do-abstract-or-ambigu
>> > >> ous-fields-in-types-interact-with-the-compiler and the section
>> > >> afterwards. You'd be better off with
>> > >>
>> > >> type Bond{T<:TermStructure}
>> > >>
>> > >> rate::Float64
>> > >> ts::T
>> > >> mat_dat::Date
>> > >>
>> > >> end
>> > >>
>> > >> --Tim
>> > >>
>> > >> On Thursday, December 31, 2015 02:42:11 PM Christopher Alexander
>> wrote:
>> > >> > Hello all,
>> > >> >
>> > >> > I have a question about the usage of circular references in types.
>> In
>> > >>
>> > >> a
>> > >>
>> > >> > project I am working on, I am running into several situations
>> where
>> > >>
>> > >> this
>> > >>
>> > >> > type of design appears to be the best issue. For example, let's
>> say I
>> > >>
>> > >> have
>> > >>
>> > >> > this (this is a massive simplification but illustrates my point):
>> > >> >
>> > >> > abstract TermStructure
>> > >> >
>> > >> >
>> > >> > type Bond
>> > >> > rate::Float64
>> > >> > ts::TermStructure
>> > >> > mat_date::Date
>> > >> > end
>> > >> >
>> > >> >
>> > >> > function Bond(rate::Float64, mat_date::Date)
>> > >> >
>> > >> > ts = NullTermStructure()
>> > >> > return Bond(rate, ts, mat_date)
>> > >> >
>> > >> > end
>> > >> >
>> > >> >
>> > >> > type NullTermStructure <: TermStructure end
>> > >> >
>> > >> >
>> > >> > type PiecewiseYieldCurve <: TermStructure
>> > >> > settlement::Date
>> > >> > bonds::Vector{Bond}
>> > >> > end
>> > >> >
>> > >> >
>> > >> > function PiecewiseYieldCurve(settlement::Date, sched::Schedule,
>> rate::
>> > >> > Float64)
>> > >> >
>> > >> > bonds = Vector{Bond}(length(sched))
>> > >> > for (i, d) in enumerate(sched)
>> > >> >
>> > >> > new_bond = Bond(rate, d)
>> > >> > bonds[i] = new_bond
>> > >> >
>> > >> > end
>> > >> >
>> > >> > pyc = PiecewiseYieldCurve(settlement, bonds)
>> > >> > for b in bonds
>> > >> >
>> > >> > b.ts = pyc
>> > >> >
>> > >> > end
>> > >> >
>> > >> > return pyc
>> > >> >
>> > >> > end
>> > >> >
>> > >> >
>> > >> > Firstly, I guess, is this the best implementation? There are
>> > >>
>> > >> situations
>> > >>
>> > >> > where I need the bonds of the PiecewiseYieldCurve to be aware of
>> the
>> > >> > TermStructure to which they are connected. Secondly, do I take a
>> > >> > performance hit from this? The PiecewiseYieldCurve instance will
>> have
>> > >> > parts of it updated as I run some of my pricer methods (not
>> shown).
>> > >> >
>> > >> > Thanks!
>> > >> >
>> > >> > Chris
>>
>>
