Bug 163330

Summary: can't support the "egrep" pattern such as "word\W"
Product: [Fedora] Fedora Reporter: han pingtian <hanpingtian>
Component: cscopeAssignee: Frank Ch. Eigler <fche>
Status: CLOSED WONTFIX QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 4   
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Hardware: i386   
OS: Linux   
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Last Closed: 2005-07-20 20:45:32 UTC Type: ---
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Description han pingtian 2005-07-15 06:40:13 UTC 
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):
cscope-15.5-12

How reproducible:


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"
  
Actual results:
although the "word\W" exists, but cscope can't find it.

Expected results:
cscope could find the pattern.

Additional info:
Comment 1 Frank Ch. Eigler 2005-07-20 20:45:32 UTC 
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.