| From: | David Johnston <polobo(at)yahoo(dot)com> |
|---|---|
| To: | pasman pasmański <pasman(dot)p(at)gmail(dot)com> |
| Cc: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: New feature: accumulative functions. |
| Date: | 2011-09-25 13:36:35 |
| Message-ID: | CAAB7D45-B119-488B-8A6C-E97C3B1E9101@yahoo.com |
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| Lists: | pgsql-general |
On Sep 25, 2011, at 9:19, pasman pasmański <pasman(dot)p(at)gmail(dot)com> wrote:
> Hi.
>
> I propose to add "accumulative" flag to a function definition. This
> flag would be set for function f(x) which is accumulative and
> immutable.
>
> This flag allows to use an index on x for clauses containing f(x):
>
> where f(x) = const
> where f(x) > const
>
> and so on.
>
>
We can term it a Schrodinger function :)
I don't understand how it can have mutable state (accumulator) and still be called immutable.
Can explain further and give an example (or better yet, real life) use-case?
David J.
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