Re: [Fwd: regular expressions, I am puzzled]

[Terrence Enger <tenger@xxxxxxxxxxxxxxxx>]

On Sun, 2009-08-02 at 13:25 -0500, Scott Klement wrote:
> Terry,
>
> Your results are exactly what I would've expected.  You didn't explain 
> what you are trying to accomplish, or why these aren't the results you 
> wanted, or what results you _do_ want, so I'm not sure how to help you 
> further.

I guess I was a bit *too* terse.

In the first case, both a regular expression tester on the web
<http://www.quanetic.com/Regex> and my program agree that regex
"(n)(u)(t*)(i)" and test string "nuttin" have matching substrings
    n
    u
    tt
    i

However, the two testers disagree about submatches for
regex ï"(n)(u)((t*)(i))" and test string "nuttin" ...
    web     mine
    ----    ----
ï    n       n
    u       u
    tti     ttu
    tt      ut
    i       t

It seems to me that my program is reporting the fourth and fifth
submatches one character too far to the left.  Can my expectaion be
wrong?

Thanks,
Terry.

> Terrence Enger wrote:
> > I have not seen this arrive from the list.  I beg your pardon if it
> > appears twice.
> >
> > -------- Forwarded Message --------
> > From: Terrence Enger <tenger@xxxxxxxxxxxxxxxx>
> > Reply-To: tenger@xxxxxxxxxxxxxxxx
> > To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
> > Subject: regular expressions, I am puzzled
> > Date: Thu, 30 Jul 2009 14:35:37 -0400
> >
> > Greetings,
> >
> > There has been a bit of discussion about regular expressions on
> > c400-l, but I am bringing my question here because I do not know
> > that my question has anything to do with the programming
> > language.  On the other hand, the regular expression APIs are
> > documented in SC41-5607-03 "ILE C/C++ Runtime Library Functions",
> > and I transcribed some stuff from QSYSINC/H(REGEX); so ya takes
> > yur chances.  For what it's worth, I am using V5R2, ILE RPG, and
> > extended regular expressions.
> >
> > My regular expression exerciser is giving results which
> > contradict both my preconceptions and the web-based exercisers
> > which I have tried.  First, a test giving the results I expect.
> > Reported from and to numbers are rm_so and rm_eo within the array
> > of regmatch_t returned from regexec().
> >
> >
> > Previous result         0         1         2         3         4         
> >                         0....+....0....+....0....+....0....+....0....+....
> >   Input string . . . :  nuttin                                            
> >   Regular expression :  (n)(u)(t*)(i)                                     
> >   Matches . . . . . .:  Sub#    Details                     Starting      
> >                         ----    ---------------------       --------
> >                            0    from 0 to 5, length 5       nutti         
> >                            1    from 0 to 1, length 1       n             
> >                            2    from 1 to 2, length 1       u             
> >                            3    from 2 to 4, length 2       tt            
> >                            4    from 4 to 5, length 1       i             
> >
> > But when I add an extra set of parentheses, the offsets of
> > subexpressions in that added subexpression sometimes are somewhat
> > reduced.
> >
> >
> > Previous result         0         1         2         3         4         
> >                         0....+....0....+....0....+....0....+....0....+....
> >   Input string . . . :  nuttin                                            
> >   Regular expression :  (n)(u)((t*)(i))                                   
> >   Matches . . . . . .:  Sub#    Details                     Starting      
> >                         ----    ---------------------       --------
> >                            0    from 0 to 5, length 5       nutti         
> >                            1    from 0 to 1, length 1       n             
> >                            2    from 1 to 2, length 1       u             
> >                            3    from 2 to 5, length 3       tti           
> >                            4    from 1 to 3, length 2       ut            
> >                            5    from 3 to 4, length 1       t             
> >
> > Within the section on extended regular expressions in "The Single
> > UNIX (R) Specification, Version 2, Regular Expressions"
> > <http://www.opengroup.org/onlinepubs/007908799/xbd/re.html>, I
> > have looked at each cause of undefined behaviour, and I don't see
> > that any of them applies to what I am doing.
> >
> > Do these results make any sense?  Or, are there any ideas about
> > what I could be doing wrong?  Should anybody care, perchance, I
> > can provide the source for my exerciser program.
> >
> > Thank you, for your attention.
> >
> > Cheers,
> > Terry.
>
> -- 
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