Symbol(3pm) Perl Programmers Reference Guide Symbol(3pm)
NAME
Symbol - manipulate Perl symbols and their names
SYNOPSIS
use Symbol;
$sym = gensym;
open($sym, "filename");
$_ = <$sym>;
# etc.
ungensym $sym; # no effect
# replace *FOO{IO} handle but not $FOO, %FOO, etc.
*FOO = geniosym;
print qualify("x"), "
"; # "Test::x"
print qualify("x", "FOO"), "
" # "FOO::x"
print qualify("BAR::x"), "
"; # "BAR::x"
print qualify("BAR::x", "FOO"), "
"; # "BAR::x"
print qualify("STDOUT", "FOO"), "
"; # "main::STDOUT" (global)
print qualify(*x), "
"; # returns *x
print qualify(*x, "FOO"), "
"; # returns *x
use strict refs;
print { qualify_to_ref $fh } "foo!
";
$ref = qualify_to_ref $name, $pkg;
use Symbol qw(delete_package);
delete_package('Foo::Bar');
print "deleted
" unless exists $Foo::{'Bar::'};
DESCRIPTION
"Symbol::gensym" creates an anonymous glob and returns a reference to it. Such a glob reference can be used as a file or directory handle.
For backward compatibility with older implementations that didn't support anonymous globs, "Symbol::ungensym" is also provided. But it
doesn't do anything.
"Symbol::geniosym" creates an anonymous IO handle. This can be assigned into an existing glob without affecting the non-IO portions of the
glob.
"Symbol::qualify" turns unqualified symbol names into qualified variable names (e.g. "myvar" -> "MyPackage::myvar"). If it is given a sec-
ond parameter, "qualify" uses it as the default package; otherwise, it uses the package of its caller. Regardless, global variable names
(e.g. "STDOUT", "ENV", "SIG") are always qualified with "main::".
Qualification applies only to symbol names (strings). References are left unchanged under the assumption that they are glob references,
which are qualified by their nature.
"Symbol::qualify_to_ref" is just like "Symbol::qualify" except that it returns a glob ref rather than a symbol name, so you can use the
result even if "use strict 'refs'" is in effect.
"Symbol::delete_package" wipes out a whole package namespace. Note this routine is not exported by default--you may want to import it
explicitly.
perl v5.8.0 2002-06-01 Symbol(3pm)
