Symbol - manipulate Perl symbols and their names
use Symbol;$sym = gensym;open($sym, "filename");$_ = <$sym>;# etc.ungensym $sym; # no effectprint 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 \*xprint qualify(\*x, "FOO"), "\n"; # returns \*xuse 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 "deleted\n" 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 didn't support anonymous globs,Symbol::ungensym is also provided. But it doesn't do anything.
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 likeSymbol::qualify except that it returns a glob ref rather than a symbol name, so you can use the result even ifuse 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.
Perldoc Browser is maintained by Dan Book (DBOOK). Please contact him via theGitHub issue tracker oremail regarding any issues with the site itself, search, or rendering of documentation.
The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. Please contact them via thePerl issue tracker, themailing list, orIRC to report any issues with the contents or format of the documentation.