On Thursday, July 14, 2016 at 10:14:38 PM UTC+2, Tim Holy wrote:
>
> *Until we get "diagonal dispatch,"* I think the only way to do this is to
> expand
> the number of arguments in the function:
>
Triangular dispatch, right? Diagonal dispatch is exactly what we have :)
> myfunc(vec::Vector) = _myfunc(eltype(vec), vec) # internal function
> _myfunc{D<:Dict{ASCIIString}}(::Type{D}, vec) = 1
> _myfunc{D}(::Type{D}, vec) = 2
>
> julia> myfunc([Dict("a"=>1), Dict("b"=>1.0)])
> 1
>
> julia> myfunc([Dict(1=>:hello), Dict(2=>:world)])
> 2
>
> Best,
> --Tim
>
> On Thursday, July 14, 2016 1:05:20 PM CDT Yichao Yu wrote:
> > On Thu, Jul 14, 2016 at 12:41 PM, David Barton <[email protected]
> <javascript:>> wrote:
> > > Hi,
> > >
> > > I'm trying to write a function that accepts a vector of values that
> are of
> > > the same (overall) type but with different parameterisations. As a
> simple
> > > example, consider the vector = [Dict("a"=>1), Dict("b"=>1.0)]. I can
> > > easily
> > > use a function along the lines of
> > >
> > > function myfunc(vec::Vector{Dict})
> > >
> > > # do something
> > >
> > > end
> > >
> > > but I'd like to be able to restrict the parameterisation slightly so
> that
> > > the first parameter of the Dict type is an ASCIIString (not my actual
> use
> > > case but follows exactly the same pattern). I've tried doing something
> > > like
> > >
> > > function myfunc{T}(vec::Vector{Dict{ASCIIString, T}})
> > >
> > > # do something
> > >
> > > end
> > >
> > > but this seems to enforce the condition that all the Dicts in the
> vector
> > > have the same parametric type T (so my example of
> myfunc([Dict("a"=>1),
> > > Dict("b"=>1.0)]) fails). Is there any way of expressing this
> constraint?
> > > Or
> >
> > The issue is the type of `[Dict("a"=>1), Dict("b"=>1.0)]` It has type
> > `Vector{Dict{String}}` which cannot be matched by the signature you
> > provide. I'm not sure if there's currently a clean way to be able to
> > match this type in additional to the more strict types.
> >
> > > will I just have to use the first form of myfunc with some extra
> checking
> > > in the function body?
> > >
> > > Thanks
> > > David
>
>
>
