The <previous> block is unique because when the Executor attempts to evaluate the output “☠,” it does not trigger the execution of the <previous> block; instead, the Executor simply reads the stored value of that output. However, when the Executor attempts to evaluate the “out” output, this (normally) triggers the execution of the <previous> block, which connects the “out” and “☠” outputs to the “in” input
•« in » : The default value is 0 (type int)
•« out » : Is the mirror image of the “in” input
•« ☠ » : Is the mirror image of the “in” input from the block’s last execution. Note that this output is a variable stored from cycle to cycle, which explains the apple-green background color. It can be initialized during the block’s first execution. When the Executor attempts to evaluate this output, it does not trigger the block’s execution <previous>
The input can be of any type; the outputs are of the same type as the input
This block allows you to create a variable that is retained from one cycle to the next. It must be present in every “loop” to ensure that “hotSwap” functions properly.
When two block chains with different periodicities are interconnected, a <previous> block must be inserted on each inter-chain link. This ensures that the slower-executing chain is not executed at the frequency of the faster chain.