YABALL

From Esolang

YABALL is a language inspired by Brainfuck, invented by Jannis Harder in 2005. Its aim is to add a more obscure code flow to Brainfuck. YABALL has a 2-dimensional code flow and 2 different flow modes. It's an acronym for Yet Another Brainfuck A Like Language. By an impossible accident the name YABALL has the same pronounciation as the Polish word for a cheap apple wine.

Contents 1 Commands 2 Modes 2.1 Normal-mode 2.2 Reverse-mode 3 Code flow 4 Misc 4.1 Cell size 4.2 Input & Output 5 Examples 6 Computational class 7 External resources

[edit] Commands

Normal-mode commands:

Command	Description
+	Increment the current cell.
-	Decrement the current cell.
>	Move to the next cell.
<	Move to the previous cell.
[	If current cell is 0 nop, else go down.
]	Go up and change to reverse-mode.
,	Input to the current cell. (see Misc Input & Output)
.	Output the current cell. (see Misc Input & Output)
?	Change to reverse-mode.
^	Go up.
v	Go down.
@	Quit the program. (Current cell is the exit code)

Reverse-mode commands:

Command	Description
!	Change to normal-mode.
9	Go up.
6	Go down.

All other commands are nop.

[edit] Modes

There are two different modes, which have their own command-set:

[edit] Normal-mode

The normal-mode is for calculations, input/output and code flow. In normal-mode the current command is executed and the program-pointer moves right. (E.g. + is: Increment the current cell and go right)

Note: ] switches in reverse-mode so it moves left and not right

[edit] Reverse-mode

The reverse-mode is for Loops and code flow. It acts like the normal-mode but moves left after the current command.

[edit] Code flow

The code filled with spaces, until all lines have the same length. If the program-pointer reaches the right end of a line, it wraps to the left of the next line. If the program-pointer reaches the left end of a line, it wraps to the right end of the previous line. The last line wraps to the first and reverse.

The use of mode switching and wrapping is a sign for good YABALL coding style.

[edit] Misc

[edit] Cell size

The cell size is 16 bit

[edit] Input & Output

Input returns -1 on EOF.

Output outputs a byte to stdout if the current cell is less than 256. If the current cell is less than 512, the value-256 is written to stderr. 512 closes stdout and 513 closes stderr. Values from 514 to 32767 inclusive are reserved for future extensions. Other values may be used for anything.

[edit] Examples

Cat (mode switching):

!,+[@
!-.]?

Cat (wrapping):

,+[@
 -v
^  .

[edit] Computational class

YABALL is Turing-complete as there are two ways converting a Brainfuck program into a YABALL program.

[edit] External resources

• Original interpreter by Jannis Harder, written in Ruby.