how could I count iterations? about context-free HOT 1 CLOSED

Context Free does not have mutable state. Variables are variables in the mathematical sense: they can have a variety of values. But once a Context Free variable is created its value cannot change. When you say iter = iter + 1 you are declaring a local variable, also named iter, that is equal to the global variableiter + 1 (i.e. 1). Outside of this SEED1 shape rule the iter global variable is in scope and has its fixed value of 0.

The best that you can do is give shape SEED1 a natural parameter that gets incremented on each recursive call. Parent shapes can send info to their children shapes through parameters but siblings shapes can never talk to each other. This is the essence of context free grammars. If you do this then you will probably want to set CF::MaxNatural to some large value.

from context-free.