Hi all, Recently, the flink community aims to add some OpenGIS functions (see FLINK-9219 <https://issues.apache.org/jira/browse/FLINK-9219>) provided in CALCITE-1968 <https://issues.apache.org/jira/browse/CALCITE-1968>. For some reasons, we plan to implement some Flink Geom types (as illustrated in this comment <https://issues.apache.org/jira/browse/FLINK-9219?focusedCommentId=16483965&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16483965>), but the private constructor in `o.a.c.r.GeoFunctions` makes that impossible.
We are confused about the protected method `bind()`, as well as other private modifiers in `o.a.c.r.GeoFunctions`. I wonder if someone could help to give some explanations about that. Do we in the right direction? Besides, maybe there should be a new Geom operand type in `o.a.c.q.t.OperandTypes`? Thanks, Xingcan
