thanks that makes sense. I initially tried %($self->{HREF}) w/ parens instead of curly braces. perl is confusing like that - you initalize a hash with parens, access and derefence with curly braces, etc.
You do not initialize hashes with parens. You can, however, initialize a hash with a list, and if you do a list assignment, you may need parenthesis for parsing precedences. But those parens are there just for precedence - they carry no syntactical meaning. Had the assignment operator been a postfix one, the parenthesis wouldn't be there.