Re: Polymorphic functions without a type

Brian Hurt <bhurt(at)janestcapital(dot)com> writes:
> In addition to providing a text function, explicitly assigning a type
> also works, so:
> select equals(null :: int, null);

This must be so if you think about it: the meaning of equality depends
on what type you are talking about, so equals() cannot work in a vacuum.
You have to give the parser some clue what type you want the inputs to
be understood as.

In most real-world cases you're not going to be passing the thing
literal constants, but expressions involving table columns, which will
have well-defined types already. So I don't see this as a major problem
in practice. I'd avoid adding a separate equals(text,text) function,
as that's most likely not going to do much except risk "capturing" cases
you'd rather had not gotten interpreted as text equality.

regards, tom lane