We need a way to request direct replies to a note

[arthurfranca]

Currently, if we use the filter { kinds: [1], #e: ['note id'] }, it won't bring only the direct replies to the note, making it hard (impossible?) to lazily (e.g. infinite scroll) build a thread, specially the ones with lots of engagement.

This is because of:

• NIP-08 (Handling Mentions) supporting clients can add extra e tags mentioned in content
• NIP-10 supporting clients can add many e tags (1 root, maybe 1 reply and maybe one or more mentions)

There is no way to fetch just the direct replies (that would be the NIP-10 with the root marker OR the NIP-10 with the reply marker; it depends).

Currently, nostr expects clients to fetch all thread at once (which will probably get limited by relays when the thread is big). It gets really difficult when you use limit on the request filter as it will sort by created_at desc, so it may retrieve latest non-direct replies or mentions. E.g.: { kinds: [1], #e: ['root note id'], limit: 10 } may bring 2 mentions and 8 replies not directed to the root note

So i think we need to add a tag denoting direct reply. Maybe an R tag (just one max per event).

What do you think of adding it so that a client can use the following filter? { kinds: [1], #R: ['note id or long form content address'], limit: 10 }

And this should supersede NIP-10 reply marker.