Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  <20192020  Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  <20192020 
<== Date ==> <== Thread ==>

Subject: Re: pyepics autosave
From: Mark Rivers via Tech-talk <tech-talk@aps.anl.gov>
To: Sandeep Kumar Malu - UKRI STFC <sandeep-kumar.malu@stfc.ac.uk>, "Matt Newville" <newville@cars.uchicago.edu>
Cc: "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Date: Fri, 6 Sep 2019 12:58:40 +0000
Hi Matt,


> Is there a published regex expression for valid PV names?


The Applications Developer's Guide (https://epics.anl.gov/base/R3-15/6-docs/AppDevGuide.pdf) says this:


**********************

6.3.2 Unquoted Strings

In the summary section, some values are shown as quoted strings and some unquoted. The actual rule is that any string consisting of only the following characters does not need to be quoted unless it contains one of the above keywords:

a-z A-Z 0-9 _ + - : . [ ] < > ;

These are all legal characters for process variable names, although . is not allowed in a record name since it separates the record from the field name in a PV name. Thus in many cases quotes are not needed around record or field names in database files. Any string containing a macro does need to be quoted though.

**********************


So it lists characters that are allowed in PV names, although it is in the section on unquoted strings.


I am quite sure that NSLS-II is using { and } in PV names which are not on the above list. It works but there was at least one case where it caused problems.


Mark



________________________________
From: tech-talk-bounces@aps.anl.gov <tech-talk-bounces@aps.anl.gov> on behalf of Matt Newville via Tech-talk <tech-talk@aps.anl.gov>
Sent: Friday, September 6, 2019 7:45 AM
To: Sandeep Kumar Malu - UKRI STFC
Cc: tech-talk@aps.anl.gov
Subject: Re: pyepics autosave

Hi Sandeep,

On Fri, Sep 6, 2019 at 4:46 AM Sandeep Kumar Malu - UKRI STFC via Tech-talk <tech-talk@aps.anl.gov<mailto:tech-talk@aps.anl.gov>> wrote:
Hi,

I am trying to save some of the PVs following the link
https://cars9.uchicago.edu/software/python/pyepics3/autosave.html

However when I try to save PVs which has hyphen ("-") e.g .  Z-CAM:WARNING thows an exception "Expected end of line, found '-' ". But all other PVs autosave works fine. Any way to fix it?


Oh, yes, I see that this module is making bad assumptions about what a PV name can be.  This is at
https://github.com/pyepics/pyepics/blob/master/epics/autosave/save_restore.py#L184

which currently reads:
    pv_name = Word(alphanums+":._$()")

That would definitely need a '-' added.    For now, you could just add that to the `epics/autosave/save_restore.py` file on your system to see if that fixes the problem.

I believe this should also allow '{' and '}', but I'm not sure if there are other characters that should be allowed.

Is there a published regex expression for valid PV names?

--Matt



Replies:
Re: pyepics autosave Johnson, Andrew N. via Tech-talk
References:
pyepics autosave Sandeep Kumar Malu - UKRI STFC via Tech-talk
Re: pyepics autosave Matt Newville via Tech-talk

Navigate by Date:
Prev: Re: pyepics autosave Matt Newville via Tech-talk
Next: RE: pyepics autosave Sandeep Kumar Malu - UKRI STFC via Tech-talk
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  <20192020 
Navigate by Thread:
Prev: Re: pyepics autosave Matt Newville via Tech-talk
Next: Re: pyepics autosave Johnson, Andrew N. via Tech-talk
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  <20192020 
ANJ, 06 Sep 2019 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·