Dranoer

Dranoer (Draw but not erase) is an esolang by User:ChuckEsoteric08.

Description

It uses a binary tape unbounded in both directions. Program runs in an implicit loop, it has these instructions:

• 1 - Set current cell to 1. If the cell is already 1 do nothing
• > - Move tape pointer to the right
• < - Move tape pointer to the left
• { - If current cell is 0 jump to matching }
• ( - If current cell is 1 jump to matching )
• }, ) - NOPs, only used as targets for if statements

Optional I/O commands:

• * - input an ASCII character and store it as a binary in the current cell and the next 7 cells (whether big or little endian depends on implementation)
• ! - output current cell as well as the next 7 cells as an ASCII character

Computational class

Dranoer is Turing-complete. One way to do this is by simulating binary Turing machine without ability to set 1 to 0 (which is still Turing-complete for the same reason as brainfuck minus - and Wang program without erase instruction). After the cell there would be a group of binary strings of equal lengths, with a single bit being 1 which repressents the statee, with tape pointer pointing at the start of one of these grpups. A cell with the value B thus looks like that (with three states as an example):

[1][B] [1][0][0] [0][1][0] [0][0][1]

That cell with the value 1 here is only needed to show that it is initialized. Program starts with initialization:

(
 init
)

It initializes all cells like it is shown above and then pointer is moved to the initial state after the current cell. Then it checks what current state is:

>>>{
 state transition, moves to three cells after the start of the group representing the next state
 }<<<

State transition first needs to move pointer to B and check if it a is correct value. If state transition moves the pointer it should check if cell left of B is 0, and if it is then it should be initialized. As seen in the proof (...) is used only a few times so it is possible to remove it, though it makes the program larger.

See also

• Unfrozen Pointer - can be seen as a subset of Dranoer
• MFJZ