Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Fri, 08 Jul 2005 13:19:27 -0500

Benjamin Franksen wrote:

Another point: What is the use of the method definition, apart from

generating a C++ member declaration? If there is no other use, we can

avoid it by using a regular top-level procedure, as shown in my

proposal on the wiki. I ask because I find it somewhat ugly to cite a

foreign language (C++) term inside the dbd file. I know, we already do

this for DBF_NO_ACCESS fields, but I never liked that one either (and I

believe it can be avoided, too).

It also documents the methods available for the record support user, and

means we don't have to have your parallel xxxStructSupport.h file which

contains just those declarations. The DBD file contains the *complete*

interface to the structure and its methods, and the record support code

that calls it is easier to understand. If the method is short enough it

could even be defined inline inside the string itself..

It would be possible to replace the line
    method("STATUS constrain(ValType &value)")
with something like
    method(constrain) {
        returns(STATUS)
        argument(value, reference(ValType))
    }

but IMHO that would be pointless - it's less flexible, a lot more effort

to parse and convert, and totally unnecessary since the only direct

interface we're providing to the structure is through C++ code anyway.

One minor detail: We should have a consistent scheme for C/C++ entities

generated from dbd definitions.

Agreed, although we might need reminding about that later once we get to

that level of detail.

Wow. A dedicated DBD/DB extension language. Let me think a while

about /that/ one, before I comment...

Please don't spend time on that, IMHO it's way too ambitious to ever

happen (unless you're also offering to do all the work implementing it

as well...).

- Andrew
--
Podiabombastic: The tendency to shoot oneself in the foot.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System