JSON builder

[lemire]

Some users would like simdjson to help build JSON files.

See discussion at #2086

cc @jkeiser

[jkeiser]

#1327 is related and probably duplicate.

[jkeiser]

The fastest way to get this done is definitely to create a new API for it. However, users often want the ability to edit, so a DOM builder is probably OK as well (though it would be more complicated).

As for On Demand, there are possibilities for speed: since On Demand already knows the JSON text for each existing token, it can preserve that text and insert/delete values by slicing and dicing the existing text and adding new text chunks via something like a rope. (Without a rope, one is likely going to spend a lot of time copying in the insert/delete case.)

[lemire]

I think that @xelatihy's issue is only for On Demand.

[xelatihy]

For many needs, and ours certainly, OnDemand is a preference and editing is not. Meaning that creating/serializing JSON in a "streaming" fashion is fine. Editing requires a significant more complex API and, I am assuming, implementation.

[nmaludy]

+1 Would like to see this as well.

[AsterDY]

+1 Would like to see this as well.

• 10000x. No-Builder-Support will definitely limit your libs' applicability and practicability

[paulocoutinhox]

+1 Please!

[wangjieest]

+1 Please!

[FranciscoThiesen]

@lemire I will start working on this!

[FranciscoThiesen]

@lemire even though this is likely to be a multi-person effort, can you assign it to me?

[lemire]

@FranciscoThiesen I just did.

Note that I recommend starting small. Do not try to solve the problem at once. Just implement something. There will be plenty of feedback.

[Steveantor]

Any progress updates 👏? @FranciscoThiesen