Re: any, anyelement, and anyarray

Thomas Hallgren <thomas@tada.se> writes:
> I've been trying to use "any" with no luck. How do I declare a function 
> that takes an "any" as a parameter?

ANY is a reserved word, so to use it as a type name you need quotes:

regression=# create function foo("any") returns int as '' language sql;
ERROR:  SQL functions cannot have arguments of type "any"

(This may be another reason why we went for "anyelement" ...)

> I realize that it would be trickier to return an "any" since the 
> expected return type must somehow be derived from the context where the 
> function was called.

You really can't use "any" as a function result type; it's not sensible
because there's no way to infer an actual type.  There are functions for
which an "any" argument type is sensible, eg count(*), but I don't see
a use for this pseudotype as a result type.

> Wouldn't it be a good idea to let the SQL parser recognize the
> anyelement[] construct as a synonym for anyarray?

[ shrug... ]  Can't get excited about it.  It'd complicate and confuse
the documentation, as well as the code, for zero functional improvement.
I also have a gut feeling that this is really wrong anyhow.  anyarray
isn't an array, it's a placeholder.
        regards, tom lane