current_timestamp -> current_timestamp() breaking postgres

[wathiede]

Example

CREATE TABLE t (
  created_at TIMESTAMP DEFAULT current_timestamp NOT NULL
);

generates

CREATE TABLE t (
	created_at TIMESTAMP
	           DEFAULT current_timestamp()
	           NOT NULL
);

Note the () after current_timestamp, this is invalid syntax for postgres. I'm guessing you're normalizing to the built in function names as documented on https://www.cockroachlabs.com/docs/stable/functions-and-operators.html#special-syntax-forms

I know you're focused on cockroach syntax, but this formatting nit keeps your otherwise super useful utility from being useful for postgres too.

Have you considered a dialect option, or something else that would allow sqlfmt to work for non-cockroach dialects? I understand the maintenance burden on you that sort of option could entail, but this tool is the best sql formatter I've come across, so I thought I'd ask.

[maddyblue]

This kind of thing I think is not too difficult based on our current code. We could have the 0-argument function wrappers like this set an extra flag that would prevent them from printing the parens.

[pauldraper]

Workaround is to use the PostgreSQL-specific equivalent functions now() or current_timestamp(6).

The no-parens current_timestamp function is SQL standard though, so it would be good to support it.