Hi devs, I want to add some new bitwise operators to Babel parser, specifically the left shift "<<" and the right shift ">>".
To do this, I add `"< BITWISE_RIGHT_SHIFT: \">>\" >"` to binaryOperatorsTokens in babel/src/main/codegen/config.fmpp and a new SqlBinaryOperator to core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java, similar to what was done in CALCITE-4980[1]. But I have noticed this change causes an error when using SQL like `select cast(a as map<varchar multiset, map<int, int>>)`. This is because the SQL contains `>>` string, I want to know how to avoid this awkward error. Thanks. [1] https://issues.apache.org/jira/browse/CALCITE-4980 Best, hongyu guo
