The predicate script function otherwise known as pointer define.
When using conditional statements in a point of code it can of be got closer to whats called branchless prediction.
so
pd ' a similar to asm like code for positioning branchless prediction code throughout the script relative to pointers '. Declaring before hand allows for better compiler optimisation although you can declare a pd function anywhere in the point of code for more controlled optimisation and you don't have to code forward to pointers.