Typeglobs

An entry in Perl's symbol table (written *foo).
Seven parts to *foo: addresses of $foo, @foo, %foo, &foo, filehandle foo, dirhandle foo, format foo.
Perl lets you use a glob wherever you would use a filehandle, so globs are often used to pass filehandles to a subroutine:
open(HANDLE, $filename) or die; mysub(*HANDLE);

Also seen in aliasing:

*foo = *bar; # mass alias $foo = \&bar; # single alias

Combine with closures for dynamic subroutine generation:

foreach my $color (qw(red green blue)) { no strict 'refs'; *$color = sub { return "<FONT COLOR=$color>@_</FONT>" }; }

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YAPC 2000: Stages of a Perl Programmer - 32