(except for the ";;")

Two adjacent semi-colons act exactly the same as a single semicolon. Effectively there is a blank statement (noop) between them.

The difference is that my REPL accumulates what I type until I finish a line with ;; at which point it executes everything I've typed so far as a single chunk of code.

Should "pp" ... "print Dumper($href);" works for me.

pp is just another Dumper()-like routine from Data::Dump.