Implement optimized versions of Json-related functions

[pchiusano]

Following #5634 instructions, implement optimized versions of these functions:

https://share.unison-lang.org/@unison/json/code/releases/1.3.0/latest/terms/core/Json/toText

https://share.unison-lang.org/@unison/json/code/releases/1.3.0/latest/terms/core/Json/tryUnconsText

[ChrisPenner]

I think you could implement this by using bsToTokens (here) to get your tokens, then use toEitherValue to parse what you can, if successful you'll get a Right of the Value with the leftover ByteString 👍

[pchiusano]

Looks good but I think you want to use textToTokens

[ceedubs]

There are a couple of long-standing bugs in the JSON parsing implementation. How will this relate to those? Are those going to be fixed first? Will this emulate the current behavior? I think that it would be confusing for the two implementations to provide different results.

• https://share.unison-lang.org/@unison/json-core/tickets/1
• https://share.unison-lang.org/@unison/json-core/tickets/2

[pchiusano]

That second ticket is fixed as of latest release of JSON library - by default, trailing characters aren't allowed, but there are versions of functions that allow trailing characters if you want. The library is also designed so that everything is defined in terms of the version that allows trailing characters, so all the logic for what to do about trailing characters is in pure Unison.

Aside: I'm not maintaining json-core anymore and made it private. It was getting pretty annoying to have things split up like that, kind of like http being split up into ultra granular packages. Just get the types and functions from @unison/json from now on and please report issues there as well. :)

I can fix the first ticket and then we can have the optimization apply to the latest version but @dolio can still get started on this and switch the hash over anytime. In general, it might be difficult to guarantee that the two implementations are identical in every case, but I'm fine with that--if anyone notices places where they differ in a way they actually care about, we'll at that time pick one or the other behavior based on what we think makes the most sense.

[pchiusano]

Contribution for the fixes on number parsing