Experimental Physics and
Industrial Control System

[email protected] (Tim Mooney) · Mon, 3 Feb 1997 12:43:20 -0600

re...

> If we're going to add a scripting language as an important part of EPICS, I'd
> like to see at least some passing thought given to other possible uses of
> such a language.  For instance, at the user interface, scripts might be
> invoked from within a DM screen (and scripts written by others than EPICS
> gurus).

I'm real glad to hear someone else say this.  We could take a lot of
trivial calculations out of the database if our display managers had
even a *little* smarts.  We should be able to define a widget whose
value is the result of a script.  In fact, we should allow any widget
to have its value determined in this way, and also let the end user
write scripts.  (Yeah, I know: "performance, performance, performance",
but unscripted widgets can still be fast, and it's truly stupid to have
to put calculations in the database, where they affect *real-time*
performance, just because the display manager can't do simple
arithmetic.)

If we *are* going to add a scripting language as an important part of
EPICS, it should be something we might one day run on the IOC as
well, to supplement existing run-time-programmable calculations
performed by the calc & wait records.

> Perl is a possibility here, but I think TCL is probably a better choice.
> However, I'd like to propose Python as an even better choice.

In my opinion, neither Perl not tcl are appropriate languages for this
purpose because their syntaxes are just too weird and too strewn with
subtle gotchas for casual use.  What I've seen of Python looks very
good (except for that stupid business of using indentation alone to do
what C does with curly braces.)

By the way, I've also looked at Rexx and at ScriptEase
(http://www.nombas.com), trying to find a good embedded language for
end users.  ScriptEase--a 'C' (subset) interpreter--looks good as an
embedded language, and it's available for a variety of platforms, but
it's not free.

Tim Mooney

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System