I've filed two PRs to evaluate the impact of the replacement. $ to _: https://github.com/apache/calcite/pull/1659 203.3sec, 5510 completed, 3 failed, 91 skipped, Gradle Test Run :core:test
$ to #: https://github.com/apache/calcite/pull/1660 196.7sec, 5510 completed, 53 failed, 91 skipped, Gradle Test Run :core:test There are test failures, however, both of them are almost ready. Both $ and _ are valid "Java identifier start" characters, so variable name like _3 is valid. If we use # instead of $, then code generator needs to be updated as well as it sometimes uses Java variables like $3, and #3 would become invalid. Any thoughts? Vladimir