Re: About the function current_user

Great. So if it's in the PG_KEYWORD list,  we should not use current_*()?  

------------------ Original ------------------
From: "John Naylor" <john(dot)naylor(at)enterprisedb(dot)com&gt;;
Date:&nbsp;Mon, Mar 20, 2023 04:49 PM
To:&nbsp;"Daniel Gustafsson"<daniel(at)yesql(dot)se&gt;;
Cc:&nbsp;"Pavel Stehule"<pavel(dot)stehule(at)gmail(dot)com&gt;;"Xiong He"<iihero(at)qq(dot)com&gt;;"pgsql-bugs"<pgsql-bugs(at)lists(dot)postgresql(dot)org&gt;;
Subject:&nbsp;Re: About the function current_user

On Mon, Mar 20, 2023 at 3:16 PM Daniel Gustafsson <daniel(at)yesql(dot)se&gt; wrote:

&gt; The syntax of current_user and current_role are mandated by the SQL
&gt; specification, we have this note in the documentation:
&gt;
&gt; &nbsp; &nbsp; &nbsp; &nbsp; "current_catalog, current_role, current_schema, current_user,
&gt; &nbsp; &nbsp; &nbsp; &nbsp; session_user, and user have special syntactic status in SQL: they must
&gt; &nbsp; &nbsp; &nbsp; &nbsp; be called without trailing parentheses.&nbsp; In PostgreSQL, parentheses can
&gt; &nbsp; &nbsp; &nbsp; &nbsp; optionally be used with current_schema, but not with the others."

To further illuminate why the last one is special: It's not a fully-reserved keyword:

$ grep current_ src/include/parser/kwlist.h
PG_KEYWORD("current_catalog", CURRENT_CATALOG, RESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("current_date", CURRENT_DATE, RESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("current_role", CURRENT_ROLE, RESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("current_schema", CURRENT_SCHEMA, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
PG_KEYWORD("current_time", CURRENT_TIME, RESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("current_timestamp", CURRENT_TIMESTAMP, RESERVED_KEYWORD, BARE_LABEL)
PG_KEYWORD("current_user", CURRENT_USER, RESERVED_KEYWORD, BARE_LABEL)

--
John Naylor
EDB: http://www.enterprisedb.com