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[PATCH split()] split()'s unused captures should be undef, not ''
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From:
Jeff 'japhy/Marillion' Pinyan
Date:
July 27, 2001 11:00
Subject:
[PATCH split()] split()'s unused captures should be undef, not ''
Message ID:
Pine.GSO.4.21.0107271358310.28213-100000@crusoe.crusoe.net
Patch below sig.
--
Jeff "japhy" Pinyan japhy@pobox.com http://www.pobox.com/~japhy/
I am Marillion, the wielder of Ringril, known as Hesinaur, the Winter-Sun.
Are you a Monk? http://www.perlmonks.com/ http://forums.perlguru.com/
Perl Programmer at RiskMetrics Group, Inc. http://www.riskmetrics.com/
Acacia Fraternity, Rensselaer Chapter. Brother #734
** Manning Publications, Co, is publishing my Perl Regex book **
--- pp.c.old Fri Jul 27 12:22:31 2001
+++ pp.c Fri Jul 27 12:23:58 2001
@@ -4228,12 +4228,16 @@
for (i = 1; i <= rx->nparens; i++) {
s = rx->startp[i] + orig;
m = rx->endp[i] + orig;
- if (m && s) {
+
+ /* japhy (07/27/01) -- the (m && s) test doesn't catch
+ parens that didn't match -- they should be set to
+ undef, not the empty string */
+ if (m >= orig && s >= orig) {
dstr = NEWSV(33, m-s);
sv_setpvn(dstr, s, m-s);
}
else
- dstr = NEWSV(33, 0);
+ dstr = &PL_sv_undef; /* undef, not "" */
if (make_mortal)
sv_2mortal(dstr);
if (do_utf8)
--- pod/perlfunc.pod.old Fri Jul 27 13:48:22 2001
+++ pod/perlfunc.pod Fri Jul 27 13:52:22 2001
@@ -4481,6 +4481,10 @@
produces the output 'h:i:t:h:e:r:e'.
+Using the empty pattern C<//> specifically matches the null string, and is
+not be confused with the use of C<//> to mean "the last successful pattern
+match".
+
Empty leading (or trailing) fields are produced when there positive width
matches at the beginning (or end) of the string; a zero-width match at the
beginning (or end) of the string does not produce an empty field. For
@@ -4540,6 +4544,11 @@
#...
}
+As with regular pattern matching, any capturing parentheses that are not
+matched in a C<split()> will be set to C<undef> when returned:
+
+ @fields = split /(A)|B/, "1A2B3";
+ # @fields is (1, 'A', 2, undef, 3)
=item sprintf FORMAT, LIST
--- t/op/split.t.old Fri Jul 27 13:46:28 2001
+++ t/op/split.t Fri Jul 27 13:48:15 2001
@@ -5,7 +5,7 @@
@INC = '../lib';
}
-print "1..45\n";
+print "1..46\n";
$FS = ':';
@@ -253,4 +253,15 @@
}
print "not " unless $r eq "he:o cruel world";
print "ok 45\n";
+}
+
+
+{
+ # split /(A)|B/, "1B2" should return (1, undef, 2)
+ my @x = split /(A)|B/, "1B2";
+ print "not " unless
+ $x[0] eq '1' and
+ (not defined $x[1]) and
+ $x[2] eq '2';
+ print "ok 46\n";
}
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