Schema language

[iboB]

Language

The decision that we will use a declarative language as a schema definition and generate everything, including C++, from there, as opposed to using C++ as a definition and generate a declarative language string from it, was made in #148

The obvious candidates are JSON and YAML. I really like TOML, but it's relatively obscure, so I'm not putting it forward here. Some thoughts

• JSON
  • very easily accessible from every language
  • somewhat unpleasant to read as the excessive use of quotation marks clutters the visual space (though helpful visualizers exist)
  • even more unpleasant to edit/write manually (though helpful editor exist)
  • we can embrace JSON Schema and try to be fully or partially compatible with it. Even more external tooling will be available if we are
• YAML
  • not every language has good parsers
  • I'd say that reading YAML is easier on the eyes than JSON
  • much more pleasant to manually edit
• Allow both?
  • while this seems like a nice middle ground it will create too much noise and put strain on the tooling
  • Instead we should choose one and if someone really prefers the other, they should be responsible in integrating a JSON↔YAML converter in their toolchain
• WIT? Protobuf? Something else? Good arguments need to be put forward for us to consider this
  • Note that the argument in "Allow both?" still applies here. If someone needs/likes, say protobuf, we can create tooling to generate .proto files from a schema

I'm leaning more towards JSON here, as it's (alas) the de facto standard for declarative data