Hi Dr. Johnson,
Thank you very much for your help! Not I understand how it works.
This problem has confused me a long time since I started learning julia.
So if I want a `mytype` object to be printed in the pretty-printed lines by
default, I have to define the display method, right?
I guess my definition of the display method is not quite correct, although
it works in REPL.
> import Base.show
> type mytype
> x::Array{Float64,2}
> end
> function show(io::IO, x::mytype)
> show(io, x.x)
> end
> function show(io::IO, m::MIME"text/plain", x::mytype)
> show(io, m, x.x)
> end
> show(STDOUT, MIME("text/plain"), mytype(x))
> function Base.display(x::mytype)
> println("mytype object:")
> show(STDOUT, MIME("text/plain"), x)
> end
> julia> x = rand(5,2)
> julia> mytype(x)
> mytype object:
> 5×2 Array{Float64,2}:
> 0.05127 0.908138
> 0.527729 0.835109
> 0.657212 0.275374
> 0.119597 0.659259
> 0.94996 0.36432
On Wednesday, September 21, 2016 at 2:27:18 PM UTC-5, Steven G. Johnson
wrote:
>
>
>
> On Wednesday, September 21, 2016 at 2:54:15 PM UTC-4, Weicheng Zhu wrote:
>>
>> Hi all,
>>
>> I have a few simple questions to ask.
>>
>> 1) What function is invoked when I type x in the following example?
>>
>
> display(x), which calls show(STDOUT, MIME("text/plain"), x) [or writemime
> in Julia ≤ 0.4]
>
>
> (Under the hood, this eventually calls a function Base.showarray)
>
>
> 2) When I define a type which takes a matrix as a member, how to define
>> the show method to print x as shown above in julia 0.5.
>> julia> type mytype
>> x::Array{Float64,2}
>> end
>> julia> mytype(x)
>> mytype([0.923288 0.0157897; 0.439387 0.50823; … ; 0.605268 0.416877;
>> 0.223898 0.558542])
>
>
> You want to define two show methods: show(io::IO, x::mytype), which calls
> show(io, x.x) and outputs everything on a single line, and show(io::IO,
> m::MIME"text/plain", x::mytype), which calls show(io, m, x.x) and outputs
> multiple pretty-printed lines.
>
>
> (You can also define additional show methods, e.g. for HTML or Markdown
> output, for even nicer display in an environment like IJulia that supports
> other MIME types.)
>
