Feature request: zero-length start/end properties

[ksa-real]

Allow access of start/end position of byte range-like structures via start / end read-only properties.

The properties are already present internally, so it looks like it won't break anything. Please let me know if I'm wrong.

[wader]

Hi, i think you can already do it if i don't misunderstand what you want to do:

$ fq '.frames[1] | tobytes, tobytesrange, tobits, tobitsrange | {start,stop,size}' doc/file.mp3
{
  "size": 208,
  "start": 0,
  "stop": 208
}
{
  "size": 208,
  "start": 2937,
  "stop": 3145
}
{
  "size": 1664,
  "start": 0,
  "stop": 1664
}
{
  "size": 1664,
  "start": 23496,
  "stop": 25160
}

So binaries has start/stop/size properties but you have to use *range function or slice to get one that is "offsetted". Just tobytes will have a zero start value.

Hope that helps and let me know if it make sense :)

[wader]

Maybe the discussion in #639 is interesting also

[ksa-real]

Yeah, I left a comment there recently. The question is why use an extra step? Why not just .frames[1].start?

[wader]

Ah sorry noticed your comment now. It's possible using _start, there are some reasons these are internal and i'm a bit reluctant to document and expose them more:

• You can do _start etc on all decode value types (number, string, array) but it becomes ambiguous what "start" means for a struct (object), is it a field "start" or the start bit range?
• Should start, stop etc be returned by keys? at the moment all _* fields are hidden from those functions as otherwise some parts of "standard" jq will act strange, ex you probably don't want ../recurse to see them.

So the current "safe" solution is that you have to use a function. But i'm open to change this if we can come up with something that don't mess too much with how one would expect jq to behave. Some new syntax could be interesting, ideally compatible with jq, but would require maintain larger change to gojq etc.

[wader]

Close for now? maybe revisit in the future if some fancier syntax for "special" properties are introduces?

[ksa-real]

Yes, closing. Underscore-prefixed items are great, somehow missed them. I guess they will stay unless something else is introduced.

[wader]

@ksa-real 👍 yeap think they will stay for now