Tim Hart <tjhart@mac.com> writes:
> On Feb 17, 2008, at 10:41 PM, Chris wrote:
> It's a string manipulation function:
> http://www.postgresql.org/docs/8.3/interactive/functions-string.html
> If the issue were simply that it were a function name, than I would
> have expected that attempting to create an enum type of 'abs' to also
> result in a quoted type.
The reason "position" is special is that the SQL spec calls out weird
specialized syntax for it:
<string position expression> ::=
POSITION <left paren> <string value expression>
IN <string value expression> <right paren>
There's no way to handle this random use of IN rather than comma,
except by having a specialized grammar production, which requires
POSITION to be a keyword.
In contrast, "abs" isn't a keyword at all in Postgres' eyes --- it's
just a function that happens to appear in the system catalogs.
regards, tom lane