name[1] == '_' && (int)strlen(name) > 2))
{
if (!isPRINT(name[1])) {
- name[3] = '\0';
+ /* 1999-02-27 mjd@plover.com */
+ char *p;
+ p = strchr(name, '\0');
+ /* The next block assumes the buffer is at least 205 chars
+ long. At present, it's always at least 256 chars. */
+ if (p-name > 200) {
+ strcpy(name+200, "...");
+ p = name+199;
+ }
+ else {
+ p[1] = '\0';
+ }
+ /* Move everything else down one character */
+ for (; p-name > 2; p--)
+ *p = *(p-1);
name[2] = toCTRL(name[1]);
name[1] = '^';
}
The new format type modifer '_' is useful for packing and unpacking
native shorts, ints, and longs. See L<perlfunc/"pack">.
+=head2 $^X variables may now have names longer than one character
+
+Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax
+error. Now variable names that begin with a control character may be
+arbitrarily long. However, for compatibility reasons, these variables
+I<must> be written with explicit braces, as C<${^XY}> for example.
+C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more
+than one control character, such as C<${^XY^Z}>, are illegal.
+
+The old syntax has not changed. As before, the `^X' may either be a
+literal control-X character or the two character sequence `caret' plus
+`X'. When the braces are omitted, the variable name stops after the
+control character. Thus C<"$^XYZ"> continues to be synonymous with
+C<$^X . "YZ"> as before.
+
+As before, lexical variables may not have names beginning with control
+characters. As before, variables whose names begin with a control
+character are always forced to be in package `main'. These variables
+are all reserved for future extensions, except the ones that begin
+with C<^_>, which may be used by user programs and will not acquire a
+special meaning in any future version of Perl.
+
=head1 Significant bug fixes
=head2 E<lt>HANDLEE<gt> on empty files
stat(), or tell can fit into a perl number without losing precision.
Work with the perl-64bit mailing list on perl.org.
-=head2 Figure a way out of $^(capital letter)
-
-Figure out a clean way to extend $^(capital letter) beyond
-the 26 alphabets. (${^WORD} maybe?)
-
=head2 Prototypes
=over 4
=head1 Recently Finished Tasks
+=head2 Figure a way out of $^(capital letter)
+
+Figure out a clean way to extend $^(capital letter) beyond
+the 26 alphabets. (${^WORD} maybe?)
+
+Mark-Jason Dominus sent a patch which went into 5.005_56.
+
=head2 Filenames
Make filenames in the distribution and in the standard module set
For more details, see the individual descriptions at L<$@>, L<$!>, L<$^E>,
and L<$?>.
+
+
+=head2 Technical Note on the Syntax of Variable Names
+
+Variable names in Perl can have several formats. Usually, they must
+begin with a letter or underscore, in which case they can be
+arbitrarily long (up to an internal limit of 256 characters) and may
+contain letters, digits, underscores, or the special sequence C<::>.
+In this case the part before the last C<::> is taken to be a I<package
+qualifier>; see L<perlmod>.
+
+Perl variable names may also be a sequence of digits or a single
+punctuation or control character. These names are all reserved for
+special uses by Perl; for example, the all-digits names are used to
+hold backreferences after a regulare expression match. Perl has a
+special syntax for the single-control-character names: It understands
+C<^X> (caret C<X>) to mean the control-C<X> character. For example,
+the notation C<$^W> (dollar-sign caret C<W>) is the scalar variable
+whose name is the single character control-C<W>. This is better than
+typing a literal control-C<W> into your program.
+
+Finally, new in Perl 5.006, Perl variable names may be alphanumeric
+strings that begin with control characters. These variables must be
+written in the form C<${^Foo}>; the braces are not optional.
+C<${^Foo}> denotes the scalar variable whose name is a control-C<F>
+followed by two C<o>'s. These variables are reserved for future
+special uses by Perl, except for the ones that begin with C<^_>
+(control-underscore). No control-character name that begins with
+C<^_> will acquire a special meaning in any future version of Perl;
+such names may therefore be used safely in programs. C<^_> itself,
+however, I<is> reserved.
+
+All Perl variables that begin with digits, control characters, or
+punctuation characters are exempt from the effects of the C<package>
+declaration and are always forced to be in package C<main>. A few
+other names are also exempt:
+
+ ENV STDIN
+ INC STDOUT
+ ARGV STDERR
+ ARGVOUT
+ SIG
+
+In particular, the new special C<${^_XYZ}> variables are always taken
+to be in package C<main> regardless of any C<package> declarations
+presently in scope.
+
+
# $RCSfile: lex.t,v $$Revision: 4.1 $$Date: 92/08/07 18:27:04 $
-print "1..30\n";
+print "1..41\n";
$x = 'x';
Ignored
EOF
print $foo;
+
+# Tests for new extended control-character variables
+# MJD 19990227
+
+{ my $CX = "\cX";
+ my $CXY ="\cXY";
+ $ {$CX} = 17;
+ $ {$CXY} = 23;
+ if ($ {^XY} != 23) { print "not " }
+ print "ok 31\n";
+
+# Does the syntax where we use the literal control character still work?
+ if ($ {\18} != 17) { print "not " }
+ print "ok 32\n";
+
+ $\ e = 24; # Literal control character
+ if ($\ e != 24) { print "not " } # Literal control character
+ print "ok 33\n";
+ if ($^N != 24) { print "not " } # Control character escape sequence
+ print "ok 34\n";
+
+# Does the old UNBRACED syntax still do what it used to?
+ if ("$^XY" ne "17Y") { print "not " }
+ print "ok 35\n";
+
+ sub XX () { 6 }
+ $ {"\cN\cXX"} = 119;
+ $^N = 5; # This should be an unused ^Var.
+ $N = 5;
+ # The second caret here should be interpreted as an xor
+ if (($^N^XX) != 3) { print "not " }
+ print "ok 36\n";
+# if (($N ^ XX()) != 3) { print "not " }
+# print "ok 32\n";
+
+ # These next two tests are trying to make sure that
+ # $^FOO is always global; it doesn't make sense to `my' it.
+ #
+ eval 'my $^X;';
+ print "not " unless index ($@, 'Can\'t use global $^X in "my"') > -1;
+ print "ok 37\n";
+# print "($@)\n" if $@;
+
+ eval 'my $ {^XYZ};';
+ print "not " unless index ($@, 'Can\'t use global $^XYZ in "my"') > -1;
+ print "ok 38\n";
+# print "($@)\n" if $@;
+
+# Now let's make sure that caret variables are all forced into the main package.
+ package Someother;
+ $^N = 'Someother';
+ $ {^Nostril} = 'Someother 2';
+ $ {^M} = 'Someother 3';
+ package main;
+ print "not " unless $^N eq 'Someother';
+ print "ok 39\n";
+ print "not " unless $ {^Nostril} eq 'Someother 2';
+ print "ok 40\n";
+ print "not " unless $ {^M} eq 'Someother 3';
+ print "ok 41\n";
+
+
+}
+
+
? isALNUM(*(p)) \
: isALNUM_utf8((U8*)p))
+/* In variables name $^X, these are the legal values for X.
+ * 1999-02-27 mjd-perl-patch@plover.com */
+#define isCONTROLVAR(x) (isUPPER(x) || strchr("[\\]^_?", (x)))
+
/* The following are arranged oddly so that the guard on the switch statement
* can get by with a single comparison (if the compiler is smart enough).
*/
if (s < send)
*d = *s++;
d[1] = '\0';
- if (*d == '^' && *s && (isUPPER(*s) || strchr("[\\]^_?", *s))) {
+ if (*d == '^' && *s && isCONTROLVAR(*s)) {
*d = toCTRL(*s);
s++;
}
s = e;
}
else {
- while (isALNUM(*s) || *s == ':')
+ while ((isALNUM(*s) || *s == ':') && d < e)
*d++ = *s++;
+ if (d >= e)
+ croak(ident_too_long);
}
*d = '\0';
while (s < send && (*s == ' ' || *s == '\t')) s++;
PL_lex_brackstack[PL_lex_brackets++] = XOPERATOR;
return s;
}
+ }
+ /* Handle extended ${^Foo} variables
+ * 1999-02-27 mjd-perl-patch@plover.com */
+ else if (!isALNUM(*d) && !isPRINT(*d) /* isCTRL(d) */
+ && isALNUM(*s))
+ {
+ d++;
+ while (isALNUM(*s) && d < e) {
+ *d++ = *s++;
+ }
+ if (d >= e)
+ croak(ident_too_long);
+ *d = '\0';
}
if (*s == '}') {
s++;
https://perl5.git.perl.org / perl5.git / commitdiff