On 12/17/20 16:47, Tom Lane wrote:
> As far as "treat as" is concerned, we already have a spelling for
> that, it's called a cast.
I find them different; XQuery was the first language I had encountered
that provides both (a cast in XQuery is spelled 'cast as', just as you'd
expect), and the idea of an explicit operation that means "I am only
asserting statically what type this will have at run time; do not ever
perform any conversion or coercion, just give me an error if I'm wrong"
seems to be a distinct and useful one.
Even if there is no available SQL spelling for that, it might still one day
be a useful expression node that could be generated in certain chosen cases.
Regards,
-Chap