Re: AW: type conversion discussion - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: AW: type conversion discussion
Date
Msg-id Pine.LNX.4.21.0005190413370.349-100000@localhost.localdomain
Whole thread Raw
In response to Re: AW: type conversion discussion  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: AW: type conversion discussion  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane writes:

> (The SQL guys probably did not foresee people implementing NUMERIC
> with wider range than FLOAT ;-) ... but the fact that we did so
> doesn't give us license to ignore that aspect of the spec ...)

I think that must have been it, why else would they (implicitly) rank
floats above numerics. If we submit to that notion, then I agree with the
promotion tree you suggested.

The problem remains that upward casting will not be guaranteed to work all
the time, which is something that needs to be addressed; in potentially
unpretty ways, because not every casting decision is necessarily a linear
ladder-climb, it might be affected by other casting decisions going on in
parallel. (The workaround here could be to convert numerics that are wider
than floats to `infinity' :-)


-- 
Peter Eisentraut                  Sernanders väg 10:115
peter_e@gmx.net                   75262 Uppsala
http://yi.org/peter-e/            Sweden



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