[cmake-developers] Making your regular expression engine more reliable

[Alan W. Irwin]

I have just discovered a long-standing regular expression bug (see
<https://gitlab.kitware.com/cmake/cmake/issues/16899>) that has been
around since at least 3.0.2.

So your unit tests for regular expressions obviously missed at least
this issue. I have no idea what those unit tests are (or even if they
exist), but one possibility for attempting to wring most of the bugs out
of your regular expression processor is to adapt some other project's
regexp test suite. See
<http://stackoverflow.com/questions/15819919/where-can-i-find-unit-tests-for-regular-expressions-in-multiple-languages>
for a rather large list of such test suites.

Another possibility is simply to forget supporting your own regexp
engine and adopt someone else's very well regarded regexp engine (such
as libprng).  I vaguely recall that has been suggested before, but
since that hasn't happened I presume inertia or NIH syndrome won or
else there was some strong reason why you didn't go that route.

>From my perspective as a strongly interested CMake user (but not a
CMake developer or regexp guru) that wants a completely reliable
regular expression engine for CMake, I don't care which of these two
approaches you use to achieve that goal.  But I hope my starting
this topic here will facilitate reaching that goal.

Alan
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Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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Linux-powered Science
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