package Scalar::Util;
use strict;
+use warnings;
require Exporter;
-require List::Util; # List::Util loads the XS
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(
blessed refaddr reftype weaken unweaken isweak
- dualvar isdual isvstring looks_like_number openhandle readonly set_prototype tainted
+ dualvar isdual isvstring looks_like_number openhandle readonly set_prototype
+ tainted
);
-our $VERSION = "1.38";
-$VERSION = eval $VERSION;
-
-our @EXPORT_FAIL;
+our $VERSION = "1.63";
+$VERSION =~ tr/_//d;
-unless (defined &weaken) {
- push @EXPORT_FAIL, qw(weaken);
-}
-unless (defined &isweak) {
- push @EXPORT_FAIL, qw(isweak isvstring);
-}
-unless (defined &isvstring) {
- push @EXPORT_FAIL, qw(isvstring);
-}
+require List::Util; # List::Util loads the XS
+List::Util->VERSION( $VERSION ); # Ensure we got the right XS version (RT#100863)
+# populating @EXPORT_FAIL is done in the XS code
sub export_fail {
- if (grep { /^(?:weaken|isweak)$/ } @_ ) {
- require Carp;
- Carp::croak("Weak references are not implemented in the version of perl");
- }
-
if (grep { /^isvstring$/ } @_ ) {
require Carp;
- Carp::croak("Vstrings are not implemented in the version of perl");
+ Carp::croak("Vstrings are not implemented in this version of perl");
}
@_;
}
+# set_prototype has been moved to Sub::Util with a different interface
+sub set_prototype(&$)
+{
+ my ( $code, $proto ) = @_;
+ return Sub::Util::set_prototype( $proto, $code );
+}
+
1;
__END__
C<Scalar::Util> contains a selection of subroutines that people have expressed
would be nice to have in the perl core, but the usage would not really be high
-enough to warrant the use of a keyword, and the size so small such that being
-individual extensions would be wasteful.
+enough to warrant the use of a keyword, and the size would be so small that
+being individual extensions would be wasteful.
By default C<Scalar::Util> does not export any subroutines.
+=head2 Core Perl C<builtin> Functions
+
+Many functions in this module have served as the inspiration for a new
+experimental facility in recent versions of Perl. From various development
+versions, starting at 5.35.7, equivalent functions to many of these utilities
+are available in the C<builtin::> package.
+
+ use Scalar::Util qw(blessed);
+
+ $class = blessed $obj;
+
+ $class = builtin::blessed $obj; # equivalent
+
+For more information, see the documentation on L<builtin>.
+
=cut
=head1 FUNCTIONS FOR REFERENCES
The following functions all perform some useful activity on reference values.
-=head2 $pkg = blessed( $ref )
+=head2 blessed
+
+ my $pkg = blessed( $ref );
-If C<$ref> is a blessed reference the name of the package that it is blessed
+If C<$ref> is a blessed reference, the name of the package that it is blessed
into is returned. Otherwise C<undef> is returned.
$scalar = "foo";
Take care when using this function simply as a truth test (such as in
C<if(blessed $ref)...>) because the package name C<"0"> is defined yet false.
-=head2 $addr = refaddr( $ref )
+I<Since Perl version 5.35.7> an equivalent function is available as
+C<builtin::blessed>.
-If C<$ref> is reference the internal memory address of the referenced value is
+=head2 refaddr
+
+ my $addr = refaddr( $ref );
+
+If C<$ref> is reference, the internal memory address of the referenced value is
returned as a plain integer. Otherwise C<undef> is returned.
$addr = refaddr "string"; # undef
$obj = bless {}, "Foo";
$addr = refaddr $obj; # eg 88123488
-=head2 $type = reftype( $ref )
+I<Since Perl version 5.35.7> an equivalent function is available as
+C<builtin::refaddr>.
+
+=head2 reftype
-If C<$ref> is a reference the basic Perl type of the variable referenced is
+ my $type = reftype( $ref );
+
+If C<$ref> is a reference, the basic Perl type of the variable referenced is
returned as a plain string (such as C<ARRAY> or C<HASH>). Otherwise C<undef>
is returned.
$obj = bless {}, "Foo";
$type = reftype $obj; # HASH
-=head2 weaken( REF )
+Note that for internal reasons, all precompiled regexps (C<qr/.../>) are
+blessed references; thus C<ref()> returns the package name string C<"Regexp">
+on these but C<reftype()> will return the underlying C structure type of
+C<"REGEXP"> in all capitals.
+
+I<Since Perl version 5.35.7> an equivalent function is available as
+C<builtin::reftype>.
-The lvalue C<REF> will be turned into a weak reference. This means that it
-will not hold a reference count on the object it references. Also when the
+=head2 weaken
+
+ weaken( $ref );
+
+The lvalue C<$ref> will be turned into a weak reference. This means that it
+will not hold a reference count on the object it references. Also, when the
reference count on that object reaches zero, the reference will be set to
undef. This function mutates the lvalue passed as its argument and returns no
value.
destroyed because there is now always a strong reference to them in the @object
array.
-=head2 unweaken( REF )
+I<Since Perl version 5.35.7> an equivalent function is available as
+C<builtin::weaken>.
+
+=head2 unweaken
+
+ unweaken( $ref );
+
+I<Since version 1.36.>
The lvalue C<REF> will be turned from a weak reference back into a normal
(strong) reference again. This function mutates the lvalue passed as its
argument and returns no value. This undoes the action performed by
-C<weaken()>.
+L</weaken>.
This function is slightly neater and more convenient than the
otherwise-equivalent code
(because in particular, simply assigning a weak reference back to itself does
not work to unweaken it; C<$REF = $REF> does not work).
-=head2 $weak = isweak( $ref )
+I<Since Perl version 5.35.7> an equivalent function is available as
+C<builtin::unweaken>.
+
+=head2 isweak
+
+ my $weak = isweak( $ref );
Returns true if C<$ref> is a weak reference.
$copy = $ref;
$weak = isweak($copy); # false
+I<Since Perl version 5.35.7> an equivalent function is available as
+C<builtin::is_weak>.
+
=head1 OTHER FUNCTIONS
-=head2 $var = dualvar( $num, $string )
+=head2 dualvar
+
+ my $var = dualvar( $num, $string );
Returns a scalar that has the value C<$num> in a numeric context and the value
C<$string> in a string context.
$num = $foo + 2; # 12
$str = $foo . " world"; # Hello world
-=head2 $dual = isdual( $var )
+=head2 isdual
+
+ my $dual = isdual( $var );
+
+I<Since version 1.26.>
If C<$var> is a scalar that has both numeric and string values, the result is
true.
$dual = isdual($foo); # true
Note that a scalar can be made to have both string and numeric content through
-numeric operations:
+standard operations:
$foo = "10";
$dual = isdual($foo); # false
$bar = $foo + 0;
$dual = isdual($foo); # true
-Note that although C<$!> appears to be dual-valued variable, it is actually
-implemented using a tied scalar:
+The C<$!> variable is commonly dual-valued, though it is also magical in other
+ways:
$! = 1;
+ $dual = isdual($!); # true
print("$!\n"); # "Operation not permitted"
- $dual = isdual($!); # false
-You can capture its numeric and string content using:
+B<CAUTION>: This function is not as useful as it may seem. Dualvars are not a
+distinct concept in Perl, but a standard internal construct of all scalar
+values. Almost any value could be considered as a dualvar by this function
+through the course of normal operations.
- $err = dualvar $!, $!;
- $dual = isdual($err); # true
+=head2 isvstring
-=head2 $vstring = isvstring( $var )
+ my $vstring = isvstring( $var );
-If C<$var> is a scalar which was coded as a vstring the result is true.
+If C<$var> is a scalar which was coded as a vstring, the result is true.
$vs = v49.46.48;
$fmt = isvstring($vs) ? "%vd" : "%s"; #true
printf($fmt,$vs);
-=head2 $isnum = looks_like_number( $var )
+=head2 looks_like_number
+
+ my $isnum = looks_like_number( $var );
Returns true if perl thinks C<$var> is a number. See
L<perlapi/looks_like_number>.
-=head2 $fh = openhandle( $fh )
+=head2 openhandle
+
+ my $fh = openhandle( $fh );
-Returns C<$fh> itself if C<$fh> may be used as a filehandle and is open, or is
-is a tied handle. Otherwise C<undef> is returned.
+Returns C<$fh> itself, if C<$fh> may be used as a filehandle and is open, or if
+it is a tied handle. Otherwise C<undef> is returned.
$fh = openhandle(*STDIN); # \*STDIN
$fh = openhandle(\*STDIN); # \*STDIN
$fh = openhandle(*NOTOPEN); # undef
$fh = openhandle("scalar"); # undef
-=head2 $ro = readonly( $var )
+=head2 readonly
+
+ my $ro = readonly( $var );
Returns true if C<$var> is readonly.
$readonly = foo($bar); # false
$readonly = foo(0); # true
-=head2 $code = set_prototype( $code, $prototype )
+=head2 set_prototype
+
+ my $code = set_prototype( $code, $prototype );
Sets the prototype of the function given by the C<$code> reference, or deletes
it if C<$prototype> is C<undef>. Returns the C<$code> reference itself.
set_prototype \&foo, '$$';
-=head2 $t = tainted( $var )
+=head2 tainted
+
+ my $t = tainted( $var );
Return true if C<$var> is tainted.
=over
-=item Weak references are not implemented in the version of perl
-
-The version of perl that you are using does not implement weak references, to
-use C<isweak> or C<weaken> you will need to use a newer release of perl.
-
-=item Vstrings are not implemented in the version of perl
+=item Vstrings are not implemented in this version of perl
The version of perl that you are using does not implement Vstrings, to use
-C<isvstring> you will need to use a newer release of perl.
-
-=item C<NAME> is only available with the XS version of Scalar::Util
-
-C<Scalar::Util> contains both perl and C implementations of many of its
-functions so that those without access to a C compiler may still use it.
-However some of the functions are only available when a C compiler was
-available to compile the XS version of the extension.
-
-At present that list is: weaken, isweak, dualvar, isvstring, set_prototype
+L</isvstring> you will need to use a newer release of perl.
=back
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
-Except weaken and isweak which are
+Additionally L</weaken> and L</isweak> which are
Copyright (c) 1999 Tuomas J. Lukka <lukka@iki.fi>. All rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as perl itself.
+Copyright (C) 2004, 2008 Matthijs van Duin. All rights reserved.
+Copyright (C) 2014 cPanel Inc. All rights reserved.
+This program is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself.
+
=cut
https://perl5.git.perl.org / perl5.git / blobdiff