Re: [HACKERS] How PG parser search (build-in) function?

On Thu, 13 Jan 2000, Tom Lane wrote:

> Karel Zak - Zakkr <zakkr(at)zf(dot)jcu(dot)cz> writes:
> > I have a question... How PG parser select (build-in) function?
> > Check parser function's arguments datetypes only or check returns value
> > datetype too (for function searching in system cache ..etc)?
>
> The argument types have to be different. In general, the parser
> doesn't *know* what the return type of the function is; it has to
> discover that by looking up the function. So you can't have two
> functions of the same name unless they differ in number and/or type
> of arguments.

Well, we must use the numeric version of to_number() only and parser
must cast from numeric itself (but IMHO it is not effective convert in
to_number() string to numeric and in parser convert numeric to other
datetype. But if it not possible.. :-(

Thank!

Karel