Subject Re: [Firebird-Architect] Design of new built-in functions
Author Miroslav Penchev
On Sat, 06 May 2006 12:43:54 +0300, Dmitry Yemanov
<dimitr@...> wrote:

> All,
> Let's have a discussion on how we map new engine functions to BLR codes.
> ...
> Proposal (2) designs SDFs at the EVL layer. The engine looks up the
> hardcoded list of SDFs before querying RDB$FUNCTIONS and, if the
> function is
> SDF, it just call local functions. By "local" I mean that all SDFs are
> implemented as static functions inside EVL, the same way as engine
> functions
> are handled now. Of course, everything is passed via descriptors and
> returned via an impure area. The advantages of this approach is that is
> keeps the current layering and avoids calling the almost useless FUN
> code.
> The disadvantage is that SDFs override UDFs, so users cannot implement
> their
> own version of the built-in functions.

I am for that one. And also does not think the possibility of overriding
built-in functions as Plus. It opens the doors for everyone to make
'funny' things with Firebird server.

Miroslav Penchev