What you are trying to build is a state machine.
in reply to Iteration condition...
There are some modules available doing exactly that, such as Class::StateMachine or FSA::Rules. Have a look at them, they may very well inspire you.
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James