To get custom printing of a user-defined type, you only have to overload
the show method:
julia> type Pt
x::Int
y::Int
end
julia> Pt(1,2)
Pt(1,2)
julia> Base.show(io::IO, p::Pt) = print(io, "Pt: x=$(p.x), y=$(p.y)")
show (generic function with 86 methods)
julia> Pt(1,2)
Pt: x=1, y=2
julia> [Pt(1,2), Pt(3,4), Pt(5,6)]
3-element Array{Pt,1}:
Pt: x=1, y=2
Pt: x=3, y=4
Pt: x=5, y=6
julia> println(Pt(1,2))
Pt: x=1, y=2
julia> display(Pt(1,2))
Pt: x=1, y=2
On Monday, April 20, 2015 at 3:41:27 PM UTC-4, Matt Bauman wrote:
>
> You can take a look at xdump (
> https://github.com/JuliaLang/julia/blob/f7322fe8eb14dc06b65c05e8b8f3d1dbd89b684e/base/show.jl#L739-L759)
>
> as a starting point. Most of builtin types (like Dict) have custom display
> code to only show the user-relevant parts in a sensible manner. They do
> this by specializing the display, show, and/or print methods.
>
> On Monday, April 20, 2015 at 3:16:28 PM UTC-4, Kuba Roth wrote:
>>
>> I'm not sure if this was brought before. Basically I've got lot's of
>> fields in my custom type and would like to tweak the println function to
>> include also the field name before printing each value. This tweak will
>> tremendously help me with debugging my output.
>>
>> For instance this simplified example gives the following output:
>>
>> type myType
>> myName::Int
>> myValue::String
>> end
>>
>> Dict(7=>myType(5,"CCC"),3=>myType(3,"BBB"),1=>myType(1,"AAA"))
>>
>> And this line is the (non-existing custom prinln) output I'd like to get:
>>
>> Dict(7=>myType(myName:5,myValue:"CCC"),3=>myType(myName:3,myValue:"BBB"),1=>myType(myName:1,myValue:"AAA"))
>>
>>
>>
>>
>> Before start looking in the details I'd like to find out if anybody had
>> similar idea before? Perhaps this is not a new thing and something similar
>> already exists in the form of a library?
>>
>> The other question I have is how to make the custom print function
>> generic enough?
>> I'd like to mimic the behavior of println this way so it has to work with
>> any data type. At the moment it is not clear how println determines which
>> fields of a type to output.
>>
>> For instance for the Dict type which has these fields
>> :slots
>> :keys
>> :vals
>> :ndel
>> :count
>>
>> How can we tell only keys and values are 'printable'?
>>
>> Thank you
>>
>
