Symbol 0.02

Symbol is a Perl module created to 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"), "n"; # "Test::x"
print qualify("x", "FOO"), "n" # "FOO::x"
print qualify("BAR::x"), "n"; # "BAR::x"
print qualify("BAR::x", "FOO"), "n"; # "BAR::x"
print qualify("STDOUT", "FOO"), "n"; # "main::STDOUT" (global)
print qualify(*x), "n"; # returns *x
print qualify(*x, "FOO"), "n"; # returns *x

use strict refs;
print { qualify_to_ref $fh } "foo!n";
$ref = qualify_to_ref $name, $pkg;

use Symbol qw(delete_package);
delete_package(Foo::Bar);
print "deletedn" unless exists $Foo::{Bar::};

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 didnt support anonymous globs, Symbol::ungensym is also provided. But it doesnt 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 second 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.