That's an interesting coincidence - the biggest parser I wrote was also an SQL parser using Antlr. In fact, SQL was only part of it - it was a programming language that supported multiple flavours of embedded SQL (DB2 and Oracle). It worked but I always dreaded when it would have to be changed to support a new feature in a new release of Oracle (or DB/2).

I don't think it's an LR vs LL thing either. I feel that there is no sense of locality with parser generators; it's a bit like quantum mechanics - every rule has a "connection" to every other one. Change one seemingly small part of the Antlr grammar and some "far away" seemingly unrelated parts of the grammar can suddenly blow up as being ambiguous.

Coincidence indeed - I'm currently modifying my giant SQL grammar right now and building an AST off it. And struggling a bit with that, but that's mainly down to me not antlr.

It is strange that we're having such different experiences of it. I don't recognise your quantum view of it either, as a antlr rules, and bison, are very context-specific as they can only be triggered in the context of larger rules, and only when given piece of the target language (SQL here). They get triggered only in those very specific cases. I've never had your struggles with it. I don't understand.