Ivan Kochurkin

Yes, I think it makes sense to get rid of very long lines in generated sources.

Eventually, it's ready for review.

@parrt any chance it will be merged?

Eventually done. Some fails on C# tests, but are unrelated.

I suggest to use JSON or a simple indented tree format ([toStringTree](https://github.com/antlr/antlr4/blob/4.7/runtime/Java/src/org/antlr/v4/runtime/tree/ParseTree.java#L39) method returns similar tree).

JSON is a standard format and there are plenty libraries that support it.

Looks like it should be another error: `rule is left recursive but doesn't conform to a pattern ANTLR can handle` instead of `The following sets of rules are mutually left-recursive...

Maybe not very clear, the best message is `left recursive rules are not allowed to have user-defined argument lists`. But it's an issue for another discussion.

GitHub is not a place for performance and other questions. > Can i get some performance tips ? Try to reduce the number of rules. For example, you can use...

Moreover, I think it's more correctly to raise the error for every looped rule. For example, Kotlin compiler throws [two errors instead of one](https://pl.kotl.in/-9ZJcVGc4) for the sample: ```kt open class...