Re: Naming conventions for devices and Epics records

[Kay-Uwe Kasemir <kasemirk@ornl.gov>]

On Nov 17, 2006, at 09:49 , Lecorche Eric wrote:

> Hi,
>
> As we are starting our new Spiral2 project, I am now gathering some  
> pieces of information in order to establish naming conventions both  
> for devices and Epics records and taking into account habits  
> inherited from the existing Ganil installation.
>
> I already got a document from Diamond describing such naming  
> conventions but I would be interested by having others coming from  
> other labs.
>
> Can some labs send me some documents relevant for this topic ?

Hello Eric:

Whatever you do, write your naming standard
like a computer language definition, for example using BNF:

 <name> ::= <system> ":" <device> ":" <signal>
 <system> ::= <system-id> <system-instance> "-" <subsystem-id>  
<subsystem-instance>
 <system-instance> ::= "" | "_" <instance>
 <instance> ::= <integer> | <integer> <a-to-z>
 ...

An additional, verbose, more human readable explanation is nice,
but allow no misconception about the use of upper/lower case, '_' or  
':',
or the structure of instance numbers.

This asserts that you get parsable names, which you'll need
for name-related tools. Actually, try to write a name parser right away,
for example in perl, to
a) check if your naming standard allows parsing
b) have such a tool to check names as soon as the first person tries
   to define the first process variable.

That way, you might avoid ending up with names like  
DTL_Xyz:Gadget105:Value, wondering:
Is this the 105th gadget of the overall drift tube linac, or the 5th  
gadget on DTL #1?
How do I write a regular expression that gives me all the devices on  
DTL #2?

-Kay