Re: psql \df choose functions by their arguments

I wrote:
> I had an idea about that. I've not tested this, but I think it would be
> a trivial matter of adding a coalesce() call to make the query act like
> the type name for a not-present argument is an empty string, rather than
> NULL which is what it gets right now. Then you could do what I think
> you're asking for with

> \df foo integer ""

Actually, what would make more sense is to treat "-" as specifying
a non-existent argument. There are precedents for that in, eg, \c,
and a dash is a little more robust than an empty-string argument.
So that leads me to 0001 attached.

> As for the point about "int" versus "integer" and so on, I wouldn't
> be averse to installing a mapping layer for that, so long as we
> did it to \dT as well.

And for that, I suggest 0002. (We only need mappings for cases that
don't work out-of-the-box, so your list seemed a bit redundant.)

regards, tom lane