Experimental Physics and
Industrial Control System

Luedeke Andreas <[email protected]> · Thu, 03 Jun 2004 16:44:45 +0200

Mark Rivers wrote:
Bernhard Kuner wrote:
[...]
something like this:
file test.template {
pattern{ NAME, HOPR="9", LOPR="1", MDEL="0.1"}

I really like this suggestion.
One problem with template files now is that it is real hassle if one
wants to add an additional subsitution parameter. Suppose test.template
above does not currently support the MDEL parameter, but I want to add
it. At present, if I add it, then I have to find every substitution
file that references test.template and update it to add MDEL.
With Bernhard's suggestion, this would not be necessary. I could define
a default value for that new parameter, which would be the same as the
previous default value for that field in test.template, or if it was not
defined there, then the default value in the record. Existing
substitution files will work as they always did, but new ones can now
use the MDEL parameter.
Mark Rivers

If you specify default values in the "pattern" line, then you still have
to change all substitution files that use your extended template. Although
it becomes easier, because you just need to change the "pattern" lines.
To keep an extended template backward compatible, you would need to
specify the default values in the template file.
Two possibilities to specify default values would be:
a) where you use a substitution variable: "$(MDEL=0.1)"
b) in a comment line with a new keyword: #default{MDEL="0.1"}
+ example.subs:
file test.template {
 {NAME=X, MDEL=1}
 {NAME=Y}
}
+ test.template of type a):
record(ai,"$(NAME)") {
 field(MDEL,"$(MDEL=0.1)")
}
+ test.template of type b):
#default{MDEL="0.1"}
record(ai,"$(NAME)") {
 field(MDEL,"$(MDEL)")
}
+ dbLoadTemplate example.subs (in both cases)
record(ai,"X") {
 field(MDEL,"1")
}
record(ai,"Y") {
 field(MDEL,"0.1")
}

Andreas
--
Dr. Andreas Luedeke, SLS Operations Manager, Tel:+41-56-3104002
mailto:[email protected], http://people.web.psi.ch/luedeke

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System