Experimental Physics and
Industrial Control System

[email protected] (Gary Carr) · Mon, 03 Feb 1997 14:58:13 -0700

>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.)

I agree 100%.

>
>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

I think the real problem with trying to choose a scripting language is that
we will have a very hard time getting wide scale agreement on which
scripting language to use. Everyone has their favorite.

I would vote for Perl. There are many advantages to using a scripting
language with the widest possible user base and a large population of
knowledgable programmers. I believe Perl is by far the most popular of all
the languages mentioned. Tcl is probably second and I suspect Python is a
very distant third. I think Perl has established itself as a viable language
with a wide user base (despite a very ugly syntax). Tcl/tk is on its way
(although if it weren't for tk, tcl would be far less popular). Python is a
relatively new language and I don't think we really know at this point
whether it will be a winner or not. All three languages can do the job.  I
know that many people will argue that Python is a far more "elegant"
language, but computer science is littered with "elegant" languages that no
one uses. I'm not arguing that Python will necessarily be one of those
"elegant" loosers, but I am arguing that Python hasn't proved itself in the
market place yet, and I think Perl has.

>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System