You can check Images.jl, which defines a type Image <: AbstractArray but prints
like this:
julia> img = testimage("mandrill")
RGB Image with:
data: 3x512x512 Array{Uint8,3}
properties:
colorspace: RGB
colordim: 1
spatialorder: x y
limits: (0x00,0xff)
On Tuesday, July 29, 2014 11:17:15 AM Michael Grant wrote:
> I've answered my own question here: the key, for now, is to overload
> writemime. However, it doesn't seem that should be necessary, so I've
> commented on an existing GitHub issue
> <https://github.com/JuliaLang/julia/issues/6117#issuecomment-50502411>
> about it.
>
> The #undef issue is *not my problem. *I am not interested in printing the
> values *at all.*
>
> On Tuesday, July 29, 2014 11:08:06 AM UTC-5, Michael Grant wrote:
> > I have defined a subclass of AbstractArray for which I do *not* want to
> > use the default AbstractArray printing machinery in show.jl . My
> > assumption, apparently incorrect, is that I simply needed to overload
> > show.
> > Unfortunately, my overloaded version is never used.
> >
> > Here is some sample code. Note two things:
> > - The code contained within a named module, and Base.Array is not
> > imported, so there is not a name conflict here.
> > - The function eleltype is indeed defined, and returns T. The actual
> > eltype of this array is Scalar{T}. But the data is not stored as a
> > contiguous memory buffer containing Scalar{T} objects; it has been
> > compressed in a certain way.
> >
> > show(io::IO,x::Array) = print( io, "CVX $(eleltype(x)) $(ndims(x))D Array
> > ..." )
> > show{T,N}(io::IO,::Type{Array{T,N}}) = print( io, "CVX $(T) $(N)D Array" )
> > show(io::IO,::Type{Array}) = print( io, "CVX Array" )
> >
> > The last two lines work as expected, suggesting I'm indeed exporting if I
> > type CVX.Array or CVX.Array{Float64,2} into the REPL, my custom show
> > commands are called. But if I attempt to instantiate an instance, and show
> > that, it still calls the show.jl code; my overloaded version is ignored.
> > Here's what I get:
> >
> > 2x2 Array{Float64,2}:
> > #undef #undef
> > #undef #undef
> >
> > And here is the output of an explicit call to show(A)
> >
> > CVX Float64 2D Array ...
> >
> > I tried modifying that first line as follows
> >
> > show{T,N}(io::IO,x::Array{T,N}) = print( io, "CVX $(T) $(N)D Array ..." )
> >
> > but that didn't make a difference. I tried different combinations of
> > import/export show as well. As you probably know I do have to import it,
> > but I don't have to export (at least, I don't think so), since I'm
> > overloading. I also tried overloading print as well.
> >
> > Any hints? Thanks in advance for the help. I'm using Julia 0.3rc1 on the
> > Mac...
