ternary operator cond ? foo : bar being parsed as ?...?

Message-ID: <20050617130548.18776.qmail@lists.develooper.com>

with wordings improvements suggested by Ronald J Kimball

p4raw-id: //depot/perl@24920

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 94c1fd4..9e7e6d6 100644 (file)
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -3449,6 +3449,16 @@ construct, not just the empty search pattern.  Therefore code written
 in Perl 5.9.0 or later that uses the // as the I<defined-or> can be
 misparsed by pre-5.9.0 Perls as a non-terminated search pattern.
 
+=item Search pattern not terminated or ternary operator parsed as search pattern
+
+(F) The lexer couldn't find the final delimiter of a C<?PATTERN?>
+construct.
+
+The question mark is also used as part of the ternary operator (as in
+C<foo ? 0 : 1>) leading to some ambiguous constructions being wrongly
+parsed. One way to disambiguate the parsing is to put parentheses around
+the conditional expression, i.e. C<(foo) ? 0 : 1>.
+
 =item %sseek() on unopened filehandle
 
 (W unopened) You tried to use the seek() or sysseek() function on a

diff --git a/toke.c b/toke.c
index ad50ec5..ac7599e 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -9261,8 +9261,12 @@ S_scan_pat(pTHX_ char *start, I32 type)
     PMOP *pm;
     char *s = scan_str(start,FALSE,FALSE);
 
-    if (!s)
-       Perl_croak(aTHX_ "Search pattern not terminated");
+    if (!s) {
+       char *delimiter = skipspace(start);
+       Perl_croak(aTHX_ *delimiter == '?'
+                  ? "Search pattern not terminated or ternary operator parsed as search pattern"
+                  : "Search pattern not terminated" );
+    }
 
     pm = (PMOP*)newPMOP(type, 0);
     if (PL_multi_open == '?')