Cue commands that generate json/other files should have the option --compact

[rudifa]

Is your feature request related to a problem? Please describe.
While commands def, export and eval generate indented json files, in some applications the compact (minified) json is desirable, for space and time economy.

Describe the solution you'd like
cue export data.cue --compact should produce a compact data.json file.

Describe alternatives you've considered
I can reformat the indented json file with jq or any similar tool, but getting it on demand from cue would be more efficient.

Additional context
The only mention of compact in CUE issues and in pull requests I could find is in PR #1549, suggested as a possibility by @mpvl and commented on favourably by @rogpeppe and @felixge.

While the desired effect of --compact is obvious for json, for other formats discussed in #1549 probably should be 'minify', i.e. remove anything that conveys no machine readable information.

[myitcv]

Modulo naming, this seems a reasonable feature request.

[jpluscplusm]

Please include the comma-delimited, white-space-removed (comments removed?) single-line form of CUE in the set of output formats being targeted by this Issue's putative option.

[myitcv]

Updated the title to reflect that this request is not specific to JSON, but could/should be applied to all output formats.

[rudifa]

#2492 was more a convergent request than a duplicate of this one.

I limited my request to JSON because it corresponds to the immediate need of my project, but

• it is not an urgent need: it is easy to post process the indented JSON
• it would be more efficient if compacting could be done on demand in the serialization step

Questions, for my CUEducation:

• is "comma-delimited, white-space-removed single-line form of CUE" format currently supported on input to CUE?
• if yes, where is this format specified?
• or would this be a display-only format?

[jpluscplusm]

[snip]

Questions, for my CUEducation:

Unofficial answers from an enCUEsiast, rather than someone who definitively knows what they're taking about:

• is "comma-delimited, white-space-removed single-line form of CUE" format currently supported on input to CUE?

Yes. If you use the rudimentary tr|tr|sed I outlined in the duplicate Issue (after having manually removed any CUE comments), you /should/ find it transforms simple enough CUE texts into acceptable single-line equivalents. As noted, it doesn't handle multi-line strings or comments, and I'm not even sure that comments /can/ be handled in a single-line form.

I'm confident there are also other corner cases it fails to deal with.

• if yes, where is this format specified?

This section of the language guide might be useful: https://cuelang.org/docs/references/spec/#lexical-elements

I didn't use that, however - it was more trial and error :-)

• or would this be a display-only format?

I'm not sure a display-only form of the language exists. Personally, I'm only interested in a form that can be used as input.

[rudifa]

@jpluscplusm Thank you for the guidance, I'll follow it up (not as my first priority).

By 'display-only format' I meant something like this, for use in testing

    assert.Equal(`{·str: "hello world"·num: 42·flt: 3.14·"k8s.io/annotation": "secure-me"·list: ["a", "b", "c", 1, 2, 3]·obj: {·foo: "bar"·L: ["a", "b", "c", 1, 2, 3]·}·}`,
		myfmt.CompactCueVal(cueval), "-")

[yujunz]

Is there anyone already working on this?