Härdfïsh

Härdfïsh is a cross-over of Brainfuck and Hardfish. It introduces the  instruction from Brainfuck which is used to input a character (ASCII) whereas EOF is represented as 257. It also has cells which can be switched by using the instructions. Additionally, it introduces the possibility of loops which repeat everything between for as long as the current cell is not one. The  instruction from Hardfish works on a per loop basis i.e.  is executed as   and   is executed as. is expanded starting at the inner most loops and then repeat until all expressions have been expanded. As with Hardfish , and  and   as well as   is illegal.

Setting a cell to one
If the collatz conjecture is true then easily  will set the cell to one, except if the cell is 255 because then it will wrap to 0 and then  will loop forever.

Computational class
.