rdf from-jelly: limiting frames in output

[Ostrzyciel]

Add parameters like

--from-frame=10

--take-frames=3

--until-frame=4

to only output a subset of the input stream.

Not sure how to best realize this. Maybe with a single parameter that takes a python-style indexer?

Something like:

--take-frames=:10
--take-frames=2:
--take-frames=2:10
--take-frames=5

I'd support only this subset of indexing patterns to avoid massive headaches.

[Ostrzyciel]

@bswck Pythonist-Syntactist's input welcome

[johnslavik]

Acutally I'd prefer Rust range/slice syntax here

1..=10 → <1, 10>
1..10 → <1, 10)

--take-frames=..10
--take-frames=2..
--take-frames=2..10
--take-frames=5

[Ostrzyciel]

Did you mean: C# syntax?

😆

OK, fine by me.

[Ostrzyciel]

Note: the arg parsing part of this was done in #66

The work to implement this should be minimal.