Dear julia users/developers,
I am working on some toolbox for working with tensors (on a more rigorous
level, defined as elements of tensor products of vector spaces; see
https://github.com/Jutho/TensorToolbox.jl ), where the first few lines of a
new type hierarchy start as follows:
abstract AbstractTensor{S<:IndexSpace,T,N}
Base.eltype{S,T}(::AbstractTensor{S,T}) = T
Base.eltype{S,T,N}(::Type{AbstractTensor{S,T,N}}) = T
Base.eltype{TT<:AbstractTensor}(::Type{TT}) = eltype(super(TT))
spacetype{S}(::AbstractTensor{S})=S
spacetype{S,T,N}(::Type{AbstractTensor{S,T,N}})=S
spacetype{TT<:AbstractTensor}(::Type{TT})=spacetype(super(TT))
similar to some of the first lines in abstractarray.jl. The only difference
is that there is an extra parameter. In the method table (methods(eltype)
or methods(spacetype)) the order of the methods on line 3 and 4 (for
eltype) and of line 6 and 7 (for spacetype) is reversed. As a consequence,
@which eltype(AbstractTensor{ComplexSpace,Float64,3})
is caught by line 4 instead of line 3, and returns Any, whereas clearly
this should be Float64. Is there anything I do not understand of how this
works for AbstractArray and that I am doing differently, or should I file
an issue? Is there a way to force the order in which methods are added to
the method table?
Thanks,
Jutho
