Resolves issue #1013

[abetusk]

Added a '--fold' option to the command line. As discussed in the issue, this only affects pretty printing and numbers in a list.

A new process was created along with jv_print_extra_opt to leave the original functions untouched.

There is an unused structure variable in the jv_extra_opt for indentation that could be used later.

Testing is minimal (I tested it on a few examples, some of which appeared in #1013). I wasn't sure how to incorporate these changes in the tests that I saw.

[dtolnay]

Unfortunately I do not expect this to be broadly useful enough to warrant a command line flag.

If you are intending this to be used with bitmap data as in your first example, I think that is better served by this substantially simpler implementation which you could put in a library if you need it commonly:

jq <data.json -r '
    def bmp($w):
        range(0; length/$w) as $row |
        .[$row*$w : ($row+1)*$w] | join("");
    .data | bmp(32)'

If you are intending this to make JSON output with unwieldy arrays more human-readable as in your second example, I think that is better served by JSON folding provided by vim-json and similar for other editors.

Mentioning @nicowilliams in case he has a different opinion.

[nicowilliams]

I like @dtolnay's solution. Does it work for you @abetusk?

[nicowilliams]

@dtolnay's approach isn't easy to apply recursively all the way down without jq-coding a JSON encoder. A jq-coded JSON encoder is actually quite an interesting idea, as would be a jq-coded JSON parser.

[abetusk]

OK, going to close, thanks for taking a look.