functional call named notation clashes with SQL feature

[Peter Eisentraut <peter_e(at)gmx(dot)net>]

It turns out that the SQL standard uses the function call notation

foo(this AS that)

for something else:

<routine invocation> ::= <routine name> <SQL argument list>

<routine name> ::= [ <schema name> <period> ] <qualified identifier>

<SQL argument list> ::= <left paren> [ <SQL argument> [ { <comma> <SQL
argument> }... ] ] <right paren>

<SQL argument> ::= <value expression>
| <generalized expression>
| <target specification>

<generalized expression> ::= <value expression> AS <path-resolved
user-defined type name>

In systems that have inheritance of composite types, this is used to
specify which type the value is supposed to be interpreted as (for
example, to treat the value as a supertype).

Seems kind of bad to overload this with something completely different.
What should we do?