| From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, Gregory Stark <stark(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org, Brendan Jurd <direvus(at)gmail(dot)com> |
| Subject: | Re: Variadic parameters vs parameter defaults |
| Date: | 2008-12-18 09:48:53 |
| Message-ID: | 494A1C85.6050108@gmx.net |
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| Lists: | pgsql-hackers |
Tom Lane wrote:
> Yeah, I don't like putting extra restrictions on the polymorphic case
> either. Also, see my nearby note about how letting fewer defaults win
> over more defaults might be unsafe. Consider
>
> foo (f1 int)
> foo (f1 int, f2 variadic int[])
>
> If the system allows f2 to be defaulted to zero elements, then these two
> functions would have to be considered ambiguous under the stricter rule.
> This would make it *impossible* for the user to override the default
> zero-argument behavior, even with the trick of using an additional
> function.
Hmm, that use case might best be addressed by allowing the variadic
argument to be omitted (or defaulted) if all previous arguments are
omittable.
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