sub q { return "inside main sub q"; }
print "Ambiguity gets us the builtin: \n";
print q("not in sub q"), "\n";
print "Let us be more specific: \n";
print main::q("this does not get printed"), "\n";
__END__
Ambiguity gets us the builtin: 
"not in sub q"
Let us be more specific: 
inside main sub q