Multi-value query syntax discussion

[OxygenCobalt]

Continuation from #4743.

Current proposed query syntax:

• foo | [...foo...] = Match any instance of foo
• [foo...] = Match foo at the beginning
• [...foo] = Match foo at the end
• [foo,bar,baz] = Match exactly foo,bar,baz
• [...foo,bar,baz...] = Match foo,bar,baz in that order, but in any position
• [...foo,bar,baz] = Match foo,bar,baz in that order, but at the end
• [foo,bar,baz...] = Match foo,bar,baz in that order, but at the beginning

In-flux query syntax:

• foo,bar,baz = Match any instance of foo, bar, or baz, regardless of order

@jmbannon

[jmbannon]

A few out-loud thoughts:

• For most multi-tag read queries, I suspect people will not care about order
• For most multi-tag write queries, I suspect that these will be the most commonly used ops:
  • Explicitly set all values
  • Append one or many multi values
• Syntax should not collide with characters in artist's names, and be bash friendly

[sampsyo]

Right. Part of my suggestion there is that artists:foo behave differently when we know artists is a "list-valued" field, and that it would be equivalent to artists:{foo}. (We can do this because we know, when parsing the query, the types of all the fields.)

[jmbannon]

Ah okay, so basically implement the 'elementary operators' like artists:foo first, which only cares about a single element in the list (and knows how to query it properly via regex). Then, expand that by supporting the multi syntax, which really decomposes it into something like:

artists:{foo,:bar,=baz} = artists:foo artists::bar artists:=baz

[sampsyo]

That honestly sounds like a very good plan to me!

[jmbannon]

Sounds good to me as well! Will give better support to the single (artists:foo) query and simplify the contains_any (artists:{foo}) query implementation. The artists:[ordered,list] query will probably need its own special decomposition, as well as appending element(s) to the list.

While you're here @sampsyo , given @OxygenCobalt 's testimonial of everything working in the PR, mind giving it another pass and/or merge? 😉

[sampsyo]

I am hoping to get to it very soon!