HA! Here is a pure regexp that will verify that string for you...
This oughtta make some people sick...
$str = '02 s1n1 s1n2 3 s2n1 s2n2 s2n3 1 s3n1 4 s4n1 s4n2 s4n3 s4n4';
if($str =~ /^((\d+)\s+(??{ my $re = 's\d+n\d+\s*'x$+; qr($re); }))+$/) {
print "MATCH\n";
}
seemed to work with my limited testing...
On Fri, Oct 11, 2002 at 03:40:31PM -0400, Anthony R. J. Ball wrote:
>
>
> I am coming into this late... but I would use \G
>
> $str = '02 s1n1 s1n2 3 s2n1 s2n2 s2n3 1 s3n1 4 s4n1 s4n2 s4n3 s4n4';
>
> while($str =~ /\G\s*(\d+)/g) {
> my $cnt = $1;
> my @d;
>
> my $re = '\s*(s\dn\d)' x $cnt;
>
> if($str =~ /\G$re/g) {
> @d = ($1,$2,$3,$4,$5,$6,$7,$8,$9);
> print "Got $cnt: @d\n";
> } else {
>
> print "ERROR\n";
> }
>
> }
>
> of course... its a little kludgy... but assigning the regexp
> to an array unfortunately puts the g modifier in a list
> context, which blows screws up the whole thing...
>
> Other code would have to be implemented to check for bad trailing data...
>
> there is also, of course...
>
> $str =~ s/\s*(\d+)((?:\s+s\d+n\d+)*)/check($1,$2)/ge;
>
> sub check {
> my($cnt, $data) = @_;
> my @d = split /\s+/, $data;
> shift @d; #leading space
> if($cnt == @d) {
> print "Got $cnt: @d\n";
> } else {
> print "Error, expected $cnt, got ",scalar(@d),"\n";
> }
> }
>
>
> This is probably easier to deal with...
>
>
>
>
> On Fri, Oct 11, 2002 at 02:20:13PM -0400, Ranga Nathan wrote:
> > Thanks guys that was quick response;
> > In the context of Any2XML, which forces me to use a regex for top-down
> > parsing, I need to use regex. Even if the regex is slow, that is fine.
> > If it is impossible to do this in regex, of course, I would resort to
> > split().
> >
> > Can this be done using regex? Why does \1 not work? These are my
> > questions.
> >
> > Thanks again...
> >
> > ---Closing information gaps-----
> > Ranga Nathan, Reliance Technology
> > >>SEVIS solution now! http://goreliance.com
> > >>Live demo at http://any2xml.com/docs/timesheet_demo.shtml<<
> > >>Get free COBOLExplorer at http://goreliance.com/download-products <<
> >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED]] On Behalf Of Mark Aisenberg
> > > Sent: Friday, October 11, 2002 2:15 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: RE: [Boston.pm] Calling regex gurus ..A regex question..
> > >
> > >
> > > Your '\1' question aside:
> > > Your solution requires you to know the number of patterns in
> > > the string. For long strings, a regex could be slow. Why not
> > > just 'split' on whitespace into an array and then use array
> > > indices to easily extract the items you want?
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> > > On Behalf Of Ranga Nathan
> > > Sent: Friday, October 11, 2002 1:42 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: [Boston.pm] Calling regex gurus ..A regex question..
> > >
> > >
> > > I need to parse a string that has multiple occurrences of a
> > > pattern that is determined by an embeded count. For example:
> > >
> > > 02 s1n1 s1n2 3 s2n1 s2n2 s2n3 1 s3n1 4 s4n1 s4n2 s4n3 s4n4
> > >
> > > 02 is the count and I need to extract s1n1 and s2n2
> > >
> > > 3 is the count and I need to extract s2n1, s2n2 and s2n3
> > >
> > > And so on.
> > >
> > > So I tried to do:
> > > $var =
> > > /(.*?)\s+((?:.*?\s+){\1})(.*?)\s+((?:.*?\s+){\3})(.*?)\s+((?:.
> > > *?\s+){\5}
> > > )/;
> > >
> > > And was expecting "02" "s1n1 s1n2 " "3" "s2n1 s2n2 s2n3 " "1"
> > > "s3n1 " "4" "s4n1 s4n2 s4n3 s4n4 " as matches.
> > >
> > > This does not work.
> > > The \1, \2 etc are not evaluated as 'iterators'. I tried the
> > > experimental ?{} too.
> > >
> > >
> > >
> > > ---Closing information gaps-----
> > > Ranga Nathan, Reliance Technology
> > > >>SEVIS solution now! http://goreliance.com
> > > >>Live demo at http://any2xml.com/docs/timesheet_demo.shtml<<
> > > >>Get free COBOLExplorer at http://goreliance.com/download-products <<
> > >
> > > _______________________________________________
> > > Boston-pm mailing list
> > > [EMAIL PROTECTED] http://mail.pm.org/mailman/listinfo/boston-pm
> > >
> > >
> > >
> > > _______________________________________________
> > > Boston-pm mailing list
> > > [EMAIL PROTECTED] http://mail.pm.org/mailman/listinfo/boston-pm
> > >
> >
> > _______________________________________________
> > Boston-pm mailing list
> > [EMAIL PROTECTED]
> > http://mail.pm.org/mailman/listinfo/boston-pm
>
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