Symbol(l)    Perl Programmers Reference Guide   Symbol(l)



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" -> "MyPack-
       age::myvar").  If it is given a second parameter, "qual-
       ify" 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 names-
       pace.  Note this routine is not exported by default--you
       may want to import it explicitly.



perl v5.6.1                 2001-02-23              Symbol(l)