Luca Cappelletti

Added support for [`ALTER OPERATOR CLASS`](https://www.postgresql.org/docs/17//sql-alteropclass.html) syntax.

Remove Whitespace Tokens from Parser

3

This PR implements a significant architectural refactoring by moving whitespace filtering from the parser to the tokenizer. Instead of emitting whitespace tokens (spaces, tabs, newlines, comments) and filtering them throughout...

Eliminating whitespace from the parser logic

8

Hi, At this time, whitespace tokens are stored in the parser, and are then filtered out in several distinct points in the parser logic, such as: * https://github.com/apache/datafusion-sqlparser-rs/blob/67684c84d4c2589356c411ea4917dcf1defcd77c/src/parser/mod.rs#L4032-L4049 * https://github.com/apache/datafusion-sqlparser-rs/blob/67684c84d4c2589356c411ea4917dcf1defcd77c/src/parser/mod.rs#L4055-L4069...

Hi, I noticed that while there exist a more generic `Drop` variant, there also exist separate `DropFunction`, `DropDomain`, `DropSecret` etc.. and I believe that these variants could and should be...

Seemingly pointless test

1

While implementing the support for [`INHERITS`](https://www.postgresql.org/docs/current/ddl-inherit.html), I happened to find [this test](https://github.com/jmhain/sqlparser-rs/blob/7723ea56c5119c7d1a15233c18eb2aaf48b60dc0/tests/sqlparser_postgres.rs#L505-L515) which contains in its name the word `inherit` and I suppose may reference the [CREATE ROLE INHERIT](https://www.postgresql.org/docs/current/sql-createrole.html), but...