Single quotes inside variable names

[kwaping]

Debugging some ancient code at my company, I came across the following lines inside cgi-lib.cgi (remember that old staple, by Steven E. Brenner?):

$cgi_lib'bufsize  =  8192;    # default buffer size when reading multi
+part
$cgi_lib'maxbound =   100;    # maximum boundary length to be encounte
+rd
$cgi_lib'headerout =    0;    # indicates whether the header has been 
+printed

I've never seen variable names with a single quote in them before, so I wrote a very simple test.

#!/usr/bin/perl

use strict;
use warnings;

my $asdf'a = 'hi';
print $asdf'a;

When I ran it, I got the following error (regardless of my strict or warnings settings):

"my" variable $asdf::a can't be in a package near "my $asdf'a "

Can anyone explain what's going on here? It appears that a single-quote can be used in place of :: to declare namespace for variables, but I've never seen or heard of such thing before now. I assume it's a relic from an older Perl version that's now deprecated.