deprecate whos to varinfo returning a markdown table. fixes #12131.

[JeffBezanson]

julia> varinfo()
name                 size summary
–––––––––––––– –––––––––– –––––––
Base                      Module 
Core                      Module 
DelimitedFiles 90.200 KiB Module 
Main                      Module 

Classy, I say.

[StefanKarpinski]

And you didn't want Markdown parsing and formating in the base language 😛.

[JeffBezanson]

And I don't want varinfo in Base either...

[dpsanders]

Maybe this could be called variables or similar? The info seems redundant.

Also, maybe it should return a dictionary instead of just printing things out? In general returning seems more useful than printing.

[dpsanders]

I guess instead of a dict it would be a VariableInfo type.

EDIT: That prints out nicely as the above Markdown table!

[dpsanders]

(Sorry, didn't look carefully enough: It does return the Markdown table. But maybe an indexable object is more useful.)

[JeffBezanson]

I think for any serious use one should use names and other reflection functions, which make it pretty easy to get all the info you want.

[nalimilan]

I must say I feel uneasy about this design too. Returning a Markdown object really sounds like conflating contents and display. AFAIK that's the only place where we do that. Why not return a simple struct, with a custom method to print it as a Markdown table? This is what we do e.g. for StatsBase.summarystats.

(It would also make sense to have a generic type to hold lightweight tables like this, but time is a bit short to add this to 0.7.)

[StefanKarpinski]

I agree that returning a markdown object here is a bit weird. An option is that we can just document that as an interactive function whose return value is not particularly useful as data, this may change in the future. Then we can add a lightweight table type whenever we want to and return it here.

On the whole, we're not going to freeze the behavior of interactive functionality because we really want to improve the interactive experience and as long as things that used to do something useful still do a similarly useful thing, people won't be too bothered. They don't really care about identical output for varinfo for example, but they would be quite rightly annoyed if we changed the name to something completely different and examples in books and on the internet stopped working.

[JeffBezanson]

Yes, please remember what this function is really for. It's not for programmatically getting information about variables; it's terrible for that and always has been since before this it didn't even return anything. The only point of it is to provide this display, and returning a markdown table is a way to do that that works in multiple environments like ijulia. Since the purpose of this is display, it makes sense to return a display-oriented object.