On 2020-Mar-11, Tom Lane wrote: > BTW, I did not like the syntax too much. "NO DEPENDS ON EXTENSION" > doesn't seem like good English. "NOT DEPENDS ON EXTENSION" is hardly > any better. The real problem with both is that an ALTER action should > be, well, an action. A grammar stickler would say that it should be > "ALTER thing DROP DEPENDENCY ON EXTENSION ext", but perhaps we could > get away with "ALTER thing DROP DEPENDS ON EXTENSION ext" to avoid > adding a new keyword. By that logic the original command should have > been "ALTER thing ADD DEPENDS ON EXTENSION ext", but I suppose it's > too late for that.
The problem with DROP DEPENDS is alter_table_cmd, which already defines "DROP opt_column ColId", so there's a reduce/reduce conflict for the ALTER INDEX and ALTER MATERIALIZED VIEW forms because "depends" could be a column name. (It works fine for ALTER FUNCTION/ROUTINE/PROCEDURE/TRIGGER because there's no command that tries to define a conflicting DROP form for these.) It works if I change DEPENDS to be type_func_name_keyword (currently unreserved_keyword), but I bet we won't like that. (DEPENDENCY is not a keyword of any kind, so DROP DEPENDENCY require us making it one of high reservedness, which I suspect we don't like either). It would also work to use a different keyword in the DROP position; maybe REMOVE. But that's not a keyword currently. How about ALTER .. REVOKE DEPENDS or DELETE DEPENDS? Bison is okay with either of those forms. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
