Red Hat Bugzilla – Bug 163330
can't support the "egrep" pattern such as "word\W"
Last modified: 2007-11-30 17:11:10 EST
Description of problem:
The cscope has a option "Find this egrep pattern:".But when input the "word\W"
and search, it says "Could not find the egrep pattern: word\W". But the egrep
application can find the "word\W".
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1.build the cross refences file cscope.out
2.invoke the cscope
3.use the "Find this egrep pattern:" to find a pattern such as "word\W"
although the "word\W" exists, but cscope can't find it.
cscope could find the pattern.
It turns out there are many versions of egrep. cscope contains its own little
egrep implementation, probably pulled out of an older SystemV UNIX, which
predates some modern constructs. Operators like [:alnum:] or \w were not
supported in this version. I expect that cscope screen's reference to "egrep"
was meant more to indicate that a wider class of regexps are supported than
plain grep: alternation, repetition, and so on.
I hope this explains (my guess at) the reasons for the problem. Extending
cscope's egrep engine is probably not practical. I can't think of a different
term to put on the user interface that doesn't suffer from this ambiguity. I
think we'll have to live with this problem.