New deprecation warning: Dot after %s literal is concatenation

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index edccac1..fe9be76 100644 (file)
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -1524,6 +1524,17 @@ you called it with no args and both C<$@> and C<$_> were empty.
 
 See Server error.
 
+=item Dot after %s literal is concatenation
+
+(D) You had something like 0x123.456 in your code.  This is currently
+parsed as the hexadecimal number 0x123 concatenated with the decimal
+number 456, not 0x123 + 0x456/0x1000 -- we only support decimal
+decimal points.  If you meant it to be a fraction, you'll need to use
+Math::BigFloat's from_hex (or friends).  If you meant it to be
+concatenation, just put spaces around the dot to make it clearer.  In
+5.14.0, we expect to change this to mean a hex fraction.  (Of course,
+everything above applies to octal and binary constants, too.)
+
 =item %s does not define %s::VERSION--version check failed
 
 (F) You said something like "use Module 42" but the Module did not

diff --git a/t/lib/warnings/toke b/t/lib/warnings/toke
index 2236442..914c988 100644 (file)
--- a/t/lib/warnings/toke
+++ b/t/lib/warnings/toke
@@ -960,3 +960,20 @@ Use of := for an empty attribute list is deprecated at - line 36.
 Use of := for an empty attribute list is deprecated at - line 38.
 Use of := for an empty attribute list is deprecated at - line 41.
 Use of := for an empty attribute list is deprecated at - line 42.
+########
+# toke.c
+use warnings 'deprecation';
+my $a = 0123.456;
+my $b = 0x123.456;
+my $c = 0b101.010;
+no warnings 'deprecation';
+my $d = 0765.432;
+EXPECT
+Dot after octal literal is concatenation at - line 1.
+Dot after hex literal is concatenation at - line 2.
+Dot after binary literal is concatenation at - line 3.
+########
+# toke.c
+use warnings;
+my @c = 0x123..0x456;
+EXPECT

diff --git a/toke.c b/toke.c
index b5236da..7abcfb7 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -13117,6 +13117,15 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
                Perl_ck_warner(aTHX_ packWARN(WARN_SYNTAX), "Misplaced _ in number");
            }
 
+           /* Dot here is historically concat, not a radix point.
+              Deprecate that; it's confusing, and gets in the way of
+              hex(ish) fractions... but '..' is OK. */
+           if (s[0] == '.' &&
+               s[1] != '.') {
+               Perl_ck_warner(aTHX_ packWARN(WARN_DEPRECATED),
+                              "Dot after %s literal is concatenation", base);
+           }
+
            sv = newSV(0);
            if (overflowed) {
                if (n > 4294967295.0)