Define macro @display

[chrisidefix]

If you want to get a readable output of large arrays in Julia it's very convenient to use the display() function. You could use show(), but you won't be able to make much sense of a 1000 x 1000 element matrix that way. There is a macro @show, but there is none for the display() function.

It would make sense in my opinion to add a macro that could look something like this:

macro display(val)
    display(val);println()
end

[ihnorton]

See #14052 for upcoming changes to clarify the i/o situation.

There is a macro @show, but there is none for the display() function

AFAICT, julia> r and julia> display(r) are identical on 0.4 and 0.5, so a macro would be redundant...

[chrisidefix]

that may be true when you use the julia console, but if you just execute julia code writing r doesn't output display(r)

[matthieugomez]

Exactly. I think this issue should be reopened. See this discourse issue

[knuesel]

I hit this while trying to show mid-cell values in a Jupyter notebook. Using @show produces one-line outputs, which are hard to read.

Since the fix from #22253 has been reverted in #25849 , shouldn't this issue be reopened?

[mtfishman]

I think that this would be a good issue to address, since we are trying to work through issues of how to print large objects in either compact or non-compact ways (ITensor/ITensors.jl#770, ITensor/ITensors.jl#772) and I find that the macro @show is very useful for debugging, but not useful if it defaults to the compact version of show.

It sounds like #22244 stalled because the name @display wasn't considered to be quite right since the macro doesn't make sense when displaying to non-text outputs. What if @show accepted an optional mime argument, like @show [1, 2, 3] mime="text/plain"? I guess that may be breaking since it is allowed as current syntax. Or just had a different name, like @show_verbose, @show_text, etc?