Experimental Physics and
Industrial Control System

Till Straumann <[email protected]> · Fri, 02 Sep 2011 16:05:42 -0500

On 09/02/2011 03:42 PM, Ned Arnold wrote:

Maybe I misunderstand, but can't you simply replace the variable with
the same variable ... like this?

Cool - I didn't know that \ escaped a $. That's exactly what I
was looking for.

Thanks
-- T.

file dbAsyn_init.template
{
pattern
{P , R, GROUP, NAME, DLY }
{\$(P),\$(R), reg_data, IN0PD , "2" }
{\$(P),\$(R), reg_data, IN1PD , "2" }
{\$(P),\$(R), reg_data, IN2PD , "2" }
{\$(P),\$(R), reg_data, IN3PD , "2" }
{\$(P),\$(R), reg_data, IF_SLEEP , "2" }

"It works for me" ... as they say.

Ned

------------------------------------------------------------------------
*From: *"Andrew Johnson" <[email protected]>
*To: *[email protected]
*Sent: *Friday, September 2, 2011 3:01:45 PM
*Subject: *Re: how can I prevent MSI from expanding just some macros?

Hi Till,

On 2011-09-02 Till Straumann wrote:
 > I process a bunch of templates with MSI but would like the final
 > .db file to still contain macros which are to defined when the
 > .db file is loaded. Of course, this works for macros without
 > a definition but I'd like to prevent MSI from expanding a macro
 > that gives a default value:
 >
 > $(dont_expand=my_default)
 >
 > Is there a way to prevent MSI from expanding this?

The obvious way is to use something other than MSI to do this particular
expansion, but I expect it's possible to do it using MSI somehow.

Maybe instead of spelling them like you do above, you would spell those
macros
like this:

$(dont_expand$(equals)my_default)

When you run MSI it will convert that string to this:

$(dont_expand$(equals,undefined)my_default,undefined)

But that's Ok and still legal. When you're finally ready to expand the
dont_expand variable you also set equals='=' and you'll get this as a
partial
result:

$(dont_expand=my_default,undefined)

which should then properly expand the dont_expand variable and or set it to
my_default if it's not defined.

Not tested, and probably rather brittle...

- Andrew
--
Optimization is the process of taking something that works and
replacing it with something that almost works, but costs less.
-- Roger Needham

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System