Re: RfD: more powerful "any" types - Mailing list pgsql-hackers

From Tom Lane
Subject Re: RfD: more powerful "any" types
Date
Msg-id 21605.1252685489@sss.pgh.pa.us
Whole thread Raw
In response to Re: RfD: more powerful "any" types  (Merlin Moncure <mmoncure@gmail.com>)
Responses Re: RfD: more powerful "any" types
Re: RfD: more powerful "any" types
List pgsql-hackers
Merlin Moncure <mmoncure@gmail.com> writes:
> If you are going to use printf format codes, which is good and useful
> being something of a standard, I'd call routine printf (not format)
> and actually wrap vsnprintf.  The format codes in printf have a very
> specific meaning: converting native C types to arrays of characters.
> I think that a postgresql implementation should do exactly that:
> attempt to convert the passed in datum to the c type in question if
> possible (erroring if no cast exists) and then pass it down.

I think this is a bit too restrictive.  Aside from the issue of loss of
precision for NUMERIC, do we really want users to have to deal with the
fact that "long" doesn't mean the same thing on every platform?  I don't
want the same SQL to work on some platforms and fail on others because
a particular datatype has a cast to int4 and not to int8, for instance.

We should certainly leverage the C library as much as we can for this,
but exposing users to every single idiosyncrasy of C is not quite the
right thing IMHO.
        regards, tom lane


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