Goto and goto-if - page 1

Multi-datum memories have an index terminal which sets which datum within the memory is to be accessed next. And each time a datum is read the index can autoIncrement to address the next datum.

Sequences are stored in multi-datum memories. The ZOZ Executor reads them just as any other program would. Even *during* execution, a sequence can access its own sequence memory and change its own index. Changing its own index causes a "goto" for the ZOZ Executor. For example:

   A => B ; C => D ; E => F ; 1 => (own sequence)'s index

would restart the sequence at its first instruction. This is the equivalent of

   do { A => B ; C => D ; E => F; } while (forever)

Since we start with index = 1, and the ZOZ executor always reads two serial numbers at a time, all instructions start on an odd index. Specifically, the N'th instruction starts at index 2N-1. Thus:

   A => B ; C => D ; E => F ; 5 => index

would restart with "E => F", the equivalent of

   A => B ; C => D ; do { E => F ; } while (forever)