Symbol

Symbol(3)              Perl Programmers Reference Guide              Symbol(3)



NAME
       Symbol - manipulate Perl symbols and their names

SYNOPSIS
           use Symbol;

           $sym = gensym;
           open($sym, "filename");
           $_ = <$sym>;
           # etc.

           ungensym $sym;      # no effect

           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 "deleted\n" 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::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 qualfied 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.








3rd Berkeley Distribution    perl 5.005, patch 02                    Symbol(3)