REPL: make terminating with a trailing colon display output with 1000 row limit

[IanButterworth]

Updated to a single trailing :

---

This is a proposal to make terminating input in the repl with ;; a convenient way to display output without row limit.

Sometimes you just want to see the entire object, printed in the nice formatting that display provides, without truncating to the terminal window height.

When generating this the terminal window was quite short to illustrate the effect.

julia> d = Dict(i => i for i in 1:20)
Dict{Int64, Int64} with 20 entries:
  5  => 5
  16 => 16
  7  => 7
  20 => 20
  12 => 12
  8  => 8
  17 => 17
  1  => 1
  ⋮  => ⋮

julia> 

A single ; still suppresses output.

julia> d;

julia> 

Double ;; allows display to show all rows (requiring the user to scroll up)

julia> d;;
Dict{Int64, Int64} with 20 entries:
  5 => 5
  16 => 16
  7 => 7
  20 => 20
  12 => 12
  8 => 8
  17 => 17
  1 => 1
  19 => 19
  4 => 4
  6 => 6
  13 => 13
  2 => 2
  10 => 10
  11 => 11
  9 => 9
  15 => 15
  18 => 18
  14 => 14
  3 => 3

julia>

[JeffBezanson]

This is a good feature but triage does not like using more semicolons to trigger it.

[Seelengrab]

This could be done as a REPL setting ala #41435, e.g. to enable the pager.

[jariji]

I have showall(x) = show(stdout, "text/plain", x) in my startup.jl for this.

[IanButterworth]

I'll try to not die on the hill of ;;, but my proposal is to make ; in the repl conceptually an output modifier. 0 is default, 1 suppresses, 2 makes verbose, 3 ...

Did triage happen to think of any other trailing etc. chars that could be used?

[IanButterworth]

I've switched it over to if there's a trailing space.

Also, the limit now extends to 1000 rows, for safety if a very large object is displayed accidentally.

[jishnub]

I find this behavior somewhat unintuitive, as I'd expect invisible whitespace characters to not change the output. Can't this setting be more explicit, perhaps something like np.set_printoptions?

[IanButterworth]

Putting this setting under a menu does seem reasonable, I just prefer the ease of doing it very easily, something like this PR does.

If there was an options repl added, it could definitely go in there as a sticky setting too. I just think it should be achievable with some simple instruction on an individual input.

[IanButterworth]

How do people feel about a trailing colon?

julia> x
{default show limited}

julia> x;
{no show}

julia> x:
{show all (1000 row limit)}

[IanButterworth]

Marking this for a hopefully brief re-triage for the idea of using a trailing colon.

[StefanKarpinski]

Should the 1000 value be configurable somehow? Someone will inevitably ask...

[oscardssmith]

triage still doesn't like this with trailing : or the fixed number limit and thinks this should be a macro of some sort.
Possibly, this should be @pretty x (similar to @show but with pretty-printing). The name is highly bikesheddable.