Unify counts of different types

[hansihe]

Currently several different types require a count (buffer, pstring, array).

In protodef the counts of these vary slightly from type to type. In one you can only specify a prefix (pstring), and in the others you can specify either a fixed number, prefix type, or field reference. In these two different properties are used (count, countType).

I propose merging all these into a single property, count. I belive this would both require less mental overhead (less different types of count), and reduce the complexity of the implementation (I don't know how node-protodef does it, but in elixir-protodef I unify them in the first preprocess step to avoid this complexity in the later stages of the compiler).

Here are some examples of how I would imagine it looking like:

• count: ["fixed", 12]
• count: ["field", "../action"]
• count: ["prefix", "varint"]

I am obviously open to input on this syntax.

[rom1504]

Yeah something like that would definitely make sense. Related ProtoDef-io/node-protodef#35

[hansihe]

Ah, didn't see that. That's very closely related. Are there any plans to get it implemented?

[rom1504]

ProtoDef-io/node-protodef#35 talks of a general "selector" concept that might also apply to compareTo.
This might be interesting here.

The main difficulty I see is that countType implies adding the count type before the array/buffer, where other counts don't imply that.
That might not be a problem though, hard to say without implementing it.

[hansihe]

The syntax I suggested very strongly implies the type being prefixed to the type.

[roblabla]

I like hansihe's syntax better than mine. The idea is that any field that expects a "field" can either get a "fixed", "field path" or (if unremoved) "type". I don't think it'd be hard to implement countType that way, the code should more or less stay the same.

[hansihe]

Since everyone seems to agree that this is a good idea, should we come up with some kind of plan for making the change and updating the protocols that use it? Are there any other changes we should do at the same time?

[rom1504]

Yes, things that need to be done:

• update ProtoDef doc and tests
• update node-protodef and elixir-protodef
• update all .json

I believe the first step is actually updating one minecraft .json to make sure it makes sense. Then making a little script to do the transformation of the rest of them.