12345
12345.67
.23E-10 # a very small number
+ 3.14_15_92 # a very important number
4_294_967_296 # underscore for legibility
0xff # hex
+ 0xdead_beef # more hex
0377 # octal
0b011011 # binary
-You are allowed to use an underscore in numeric literals for legibility,
-but in decimal numeric literals (those written in base 10, not
-necessarily with a fractional part), digits may only be grouped in
-threes. For decimal numeric literals containing a fractional part,
-this applies only to the part before the decimal point; the fractional
-part (but not the exponent, if given!) may contain underscores
-anywhere you feel it enhances legibility. Binary, octal, and
-hexadecimal numeric literals may contain underscores in any place --
-so you could, for example, group binary digits by threes (as for a
-Unix-style mode argument such as 0b110_100_100) or by fours (to
-represent nibbles, as in 0b1010_0110) or in other groups.
+You are allowed to use underscores (underbars) in numeric literals for
+legibility, as long as the underscores are spaced at least one digit
+apart, and they do not begin or end the integer or fractional part.
+You could, for example, group binary digits by threes (as for
+a Unix-style mode argument such as 0b110_100_100) or by fours
+(to represent nibbles, as in 0b1010_0110) or in other groups.
+
+(Note that if you try to begin a number with an underscore, it won't
+even be understood as a number, it will be understood as a bareword,
+which depending on the context may mean for example a string constant,
+a function call, or a filehandle.)
String literals are usually delimited by either single or double
quotes. They work much like quotes in the standard Unix shells:
=item Misplaced _ in number
-(W syntax) An underline in a decimal constant wasn't on a 3-digit boundary.
+(W syntax) An underscore (underbar) in a numeric constant either
+immediately followed earlier underscore, or an underscore began or
+ended a numeric constant, or its fractional part (in the case of
+decimal constants) began or ended a numeric constant.
=item Missing %sbrace%s on \N{}
########
# toke.c
use warnings 'syntax' ;
-$a = 1_2;
-$a = 1_2345_6;
+$a = _123; print "$a\n"; # not a number, a string
+$a = 1_23; print "$a\n";
+$a = 1__3; print "$a\n"; # misplaced [ 5]
+$a = 123_; print "$a\n"; # misplaced [ 6]
+$a = 123._456; print "$a\n"; # misplaced [ 7]
+$a = 123.4_56; print "$a\n";
+$a = 123.4__6; print "$a\n"; # misplaced [ 9]
+$a = 123.456_; print "$a\n"; # misplaced [10]
+$a = 0b_101; print "$a\n"; # misplaced [11]
+$a = 0b1_01; print "$a\n";
+$a = 0b1__1; print "$a\n"; # misplaced [13]
+$a = 0b101_; print "$a\n"; # misplaced [14]
+$a = 0_123; print "$a\n"; # misplaced [15]
+$a = 01_23; print "$a\n";
+$a = 01__3; print "$a\n"; # misplaced [17]
+$a = 0123_; print "$a\n"; # misplaced [18]
+$a = 0x_123; print "$a\n"; # misplaced [19]
+$a = 0x1_23; print "$a\n";
+$a = 0x1__3; print "$a\n"; # misplaced [21]
+$a = 0x123_; print "$a\n"; # misplaced [22]
no warnings 'syntax' ;
-$a = 1_2;
-$a = 1_2345_6;
EXPECT
-Misplaced _ in number at - line 3.
-Misplaced _ in number at - line 4.
-Misplaced _ in number at - line 4.
+Misplaced _ in number at - line 5.
+Misplaced _ in number at - line 6.
+Misplaced _ in number at - line 7.
+Misplaced _ in number at - line 9.
+Misplaced _ in number at - line 10.
+Misplaced _ in number at - line 11.
+Misplaced _ in number at - line 13.
+Misplaced _ in number at - line 14.
+Misplaced _ in number at - line 15.
+Misplaced _ in number at - line 17.
+Misplaced _ in number at - line 18.
+Misplaced _ in number at - line 19.
+Misplaced _ in number at - line 21.
+Misplaced _ in number at - line 22.
+_123
+123
+13
+123
+123.456
+123.456
+123.46
+123.456
+5
+5
+3
+5
+83
+83
+11
+83
+291
+291
+19
+291
########
# toke.c
use warnings 'bareword' ;
Read a number in any of the formats that Perl accepts:
0(x[0-7A-F]+)|([0-7]+)|(b[01])
- [\d_]+(\.[\d_]*)?[Ee](\d+)
+ \d([\d_]*\d)?(\.\d([\d_]*\d)?)?[Ee](\d+)
Underbars (_) are allowed in decimal numbers. If -w is on,
- underbars before a decimal point must be at three digit intervals.
+ underbars must not be consecutive, and they cannot start
+ or end integer or fractional parts.
Like most scan_ routines, it uses the PL_tokenbuf buffer to hold the
thing it reads.
else if (s[1] == '.' || s[1] == 'e' || s[1] == 'E')
goto decimal;
/* so it must be octal */
- else
+ else {
shift = 3;
+ s++;
+ }
+
+ if (*s == '_') {
+ if (ckWARN(WARN_SYNTAX))
+ Perl_warner(aTHX_ WARN_SYNTAX,
+ "Misplaced _ in number");
+ lastub = s++;
+ }
base = bases[shift];
Base = Bases[shift];
default:
goto out;
- /* _ are ignored */
+ /* _ are ignored -- but warned about if consecutive */
case '_':
- s++;
+ if (ckWARN(WARN_SYNTAX) && lastub && s == lastub + 1)
+ Perl_warner(aTHX_ WARN_SYNTAX,
+ "Misplaced _ in number");
+ lastub = s++;
break;
/* 8 and 9 are not octal */
the number.
*/
out:
+
+ /* final misplaced underbar check */
+ if (s[-1] == '_') {
+ if (ckWARN(WARN_SYNTAX))
+ Perl_warner(aTHX_ WARN_SYNTAX, "Misplaced _ in number");
+ }
+
sv = NEWSV(92,0);
if (overflowed) {
if (ckWARN(WARN_PORTABLE) && n > 4294967295.0)
if -w is on
*/
if (*s == '_') {
- if (ckWARN(WARN_SYNTAX) && lastub && s - lastub != 3)
- Perl_warner(aTHX_ WARN_SYNTAX, "Misplaced _ in number");
- lastub = ++s;
+ if (ckWARN(WARN_SYNTAX) && lastub && s == lastub + 1)
+ Perl_warner(aTHX_ WARN_SYNTAX,
+ "Misplaced _ in number");
+ lastub = s++;
}
else {
/* check for end of fixed-length buffer */
}
/* final misplaced underbar check */
- if (lastub && s - lastub != 3) {
+ if (lastub && s == lastub + 1) {
if (ckWARN(WARN_SYNTAX))
Perl_warner(aTHX_ WARN_SYNTAX, "Misplaced _ in number");
}
floatit = TRUE;
*d++ = *s++;
- /* copy, ignoring underbars, until we run out of
- digits. Note: no misplaced underbar checks!
+ if (*s == '_') {
+ if (ckWARN(WARN_SYNTAX))
+ Perl_warner(aTHX_ WARN_SYNTAX,
+ "Misplaced _ in number");
+ lastub = s;
+ }
+
+ /* copy, ignoring underbars, until we run out of digits.
*/
for (; isDIGIT(*s) || *s == '_'; s++) {
/* fixed length buffer check */
if (d >= e)
Perl_croak(aTHX_ number_too_long);
- if (*s != '_')
+ if (*s == '_') {
+ if (ckWARN(WARN_SYNTAX) && lastub && s == lastub + 1)
+ Perl_warner(aTHX_ WARN_SYNTAX,
+ "Misplaced _ in number");
+ lastub = s;
+ }
+ else
*d++ = *s;
}
+ /* fractional part ending in underbar? */
+ if (s[-1] == '_') {
+ if (ckWARN(WARN_SYNTAX))
+ Perl_warner(aTHX_ WARN_SYNTAX,
+ "Misplaced _ in number");
+ }
if (*s == '.' && isDIGIT(s[1])) {
/* oops, it's really a v-string, but without the "v" */
s = start - 1;
projects / p5sagit/p5-mst-13.2.git / commitdiff