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-rw-r--r--Master/tlpkg/tlperl/lib/Scalar/Util.pm88
1 files changed, 65 insertions, 23 deletions
diff --git a/Master/tlpkg/tlperl/lib/Scalar/Util.pm b/Master/tlpkg/tlperl/lib/Scalar/Util.pm
index ab97fe5446b..da229893495 100644
--- a/Master/tlpkg/tlperl/lib/Scalar/Util.pm
+++ b/Master/tlpkg/tlperl/lib/Scalar/Util.pm
@@ -11,8 +11,22 @@ require Exporter;
require List::Util; # List::Util loads the XS
our @ISA = qw(Exporter);
-our @EXPORT_OK = qw(blessed dualvar reftype weaken isweak tainted readonly openhandle refaddr isvstring looks_like_number set_prototype);
-our $VERSION = "1.25";
+our @EXPORT_OK = qw(
+ blessed
+ dualvar
+ isdual
+ isvstring
+ isweak
+ looks_like_number
+ openhandle
+ readonly
+ refaddr
+ reftype
+ set_prototype
+ tainted
+ weaken
+);
+our $VERSION = "1.27";
$VERSION = eval $VERSION;
our @EXPORT_FAIL;
@@ -51,8 +65,9 @@ Scalar::Util - A selection of general-utility scalar subroutines
=head1 SYNOPSIS
- use Scalar::Util qw(blessed dualvar isweak readonly refaddr reftype tainted
- weaken isvstring looks_like_number set_prototype);
+ use Scalar::Util qw(blessed dualvar isdual readonly refaddr reftype
+ tainted weaken isweak isvstring looks_like_number
+ set_prototype);
# and other useful utils appearing below
=head1 DESCRIPTION
@@ -90,27 +105,40 @@ value STRING in a string context.
$num = $foo + 2; # 12
$str = $foo . " world"; # Hello world
-=item isvstring EXPR
+=item isdual EXPR
-If EXPR is a scalar which was coded as a vstring the result is true.
+If EXPR is a scalar that is a dualvar, the result is true.
- $vs = v49.46.48;
- $fmt = isvstring($vs) ? "%vd" : "%s"; #true
- printf($fmt,$vs);
+ $foo = dualvar 86, "Nix";
+ $dual = isdual($foo); # true
-=item isweak EXPR
+Note that a scalar can be made to have both string and numeric content
+through numeric operations:
-If EXPR is a scalar which is a weak reference the result is true.
+ $foo = "10";
+ $dual = isdual($foo); # false
+ $bar = $foo + 0;
+ $dual = isdual($foo); # true
- $ref = \$foo;
- $weak = isweak($ref); # false
- weaken($ref);
- $weak = isweak($ref); # true
+Note that although C<$!> appears to be dual-valued variable, it is
+actually implemented using a tied scalar:
-B<NOTE>: Copying a weak reference creates a normal, strong, reference.
+ $! = 1;
+ print("$!\n"); # "Operation not permitted"
+ $dual = isdual($!); # false
- $copy = $ref;
- $weak = isweak($copy); # false
+You can capture its numeric and string content using:
+
+ $err = dualvar $!, $!;
+ $dual = isdual($err); # true
+
+=item isvstring EXPR
+
+If EXPR 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);
=item looks_like_number EXPR
@@ -122,11 +150,11 @@ L<perlapi/looks_like_number>.
Returns FH if FH may be used as a filehandle and is open, or FH 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
-
+ $fh = openhandle(*STDIN); # \*STDIN
+ $fh = openhandle(\*STDIN); # \*STDIN
+ $fh = openhandle(*NOTOPEN); # undef
+ $fh = openhandle("scalar"); # undef
+
=item readonly SCALAR
Returns true if SCALAR is readonly.
@@ -209,6 +237,20 @@ references to objects will be strong, causing the remaining objects to never
be destroyed because there is now always a strong reference to them in the
@object array.
+=item isweak EXPR
+
+If EXPR is a scalar which is a weak reference the result is true.
+
+ $ref = \$foo;
+ $weak = isweak($ref); # false
+ weaken($ref);
+ $weak = isweak($ref); # true
+
+B<NOTE>: Copying a weak reference creates a normal, strong, reference.
+
+ $copy = $ref;
+ $weak = isweak($copy); # false
+
=back
=head1 DIAGNOSTICS