Discussion: Adding OT to Pair Programming Extension

[shadowcodex]

Pair Programming extension is great, but needs a collision algorithm and I think OT (Operational Transformation) is up for the job.

I'm going to start working on adding the functionality to https://github.com/eclipse/flux. But wanted to drop an issue here for discussion and tracking. I'll reference the issue over at the flux repo when I get over there.

eclipse-archived/flux#24

[shadowcodex]

@sunix What other backbones were you thinking of adding besides flux?

@TylerJewell Open source OT implementation I was going to use as a reference: https://github.com/Operational-Transformation/ot.js

[shadowcodex]

I am thinking that we only need to implement the inclusion side of OT.

p = position & c = character to insert & sid = identifier

void T_inc(ins(p1, c1, sid1), ins(p2,c2,sid2)){
  if (p1 < p2) { return ins(p1,c1,sid1);}
  else if (p1 == p2 && sid1 < sid2) { return ins(p1,c1,sid1)}
  else { return ins(p1 + 1, c1, sid1) }
}

we can do the exclusion side too, but doubles everything. But would allow us to support undo and locking.

void T_exc(ins(p1, c1, sid1), ins(p2,c2,sid2)){
  if (p1 < p2) { return ins(p1,c1,sid1);}
  else if (p1 == p2 && sid1 < sid2) { return ins(p1,c1,sid1)}
  else { return ins(p1 - 1, c1, sid1) }
}

[shadowcodex]

@sunix if we create a che only backbone we could use rethinkdb to hold the operations.

We could set this up as a che_sync agent to be included on workspace composer options.

[shadowcodex]

ShareDB is a database integration layer dedicated to Operational Transformation: https://github.com/share/sharedb

[ghost]

@shadowcodex do you want this issue to be opened?

[TylerJewell]

I am ok to leave this issue open as long lived issue to track discussion around pair programming.

[shadowcodex]

@eivantsov and @TylerJewell . I would leave this up for tracking this discussion as well. However I have become overloaded with system conversions and such at work. So I am unable to work on this going forward. I had high hopes for this, but I just don't have the extra time atm.

[rektide]

Perhaps an existing collaborative editing spec or project might work well for Che. Some candidates:

• TogetherJS
• Gobby's Infinote Protocol
• Atom's Teletype (very limited solution atm)
• Mobwrite
• ShareJS
• ot.js

(repasting from #2131 (comment) which is a similar, closed issue)

[rektide]

Oh! redhat-developer/rh-che#438 has a spike experimenting with either Ot.js or teletype (again very limited protocol atm). Yay!

[sunix]

@rektide the protocol is one thing but then how you use it afterwards is another. IMO what you thing is limited in atom in atom/teletype#211 can be solved in Che using the existing piece (teletype-client).

[ghost]

Closing this one. Please follow #8286