Brainfuck-ng
| Paradigm(s) | imperative |
|---|---|
| Designed by | Fernando Iazeolla |
| Appeared in | 2015 |
| Memory system | tape-based |
| Dimensions | one-dimensional |
| Computational class | Turing complete |
| Major implementations | bfng, (mirror site) |
| Influenced by | Brainfuck, ReverseFuck |
| File extension(s) | .bf |
- The title of this article may well be brainfuck-ng, due to typically being lowercased except, often, at the start of a sentence.
Brainfuck-ng is a powerful interpreter of a superset of brainfuck language. It is full compatible with brainfuck, and has in addition some enhancements.
Language overview
Brainfuck-ng operates on an array of memory cells, also referred to as the tape, each initially set to zero. There is a pointer, initially pointing to the first memory cell. The commands are:
| Command | Description |
|---|---|
>
|
Move the pointer to the right |
<
|
Move the pointer to the left |
+
|
Increment the memory cell under the pointer |
-
|
Decrement the memory cell under the pointer |
.
|
Output the character signified by the cell at the pointer |
,
|
Input a character and store it in the cell at the pointer |
[
|
Jump past the matching ] if the cell under the pointer is 0
|
]
|
Jump back to the matching [ if the cell under the pointer is nonzero
|
| ( language extentions ) | |
!
|
output the integer signified by the cell at the pointer |
?
|
Input an integer and store it in the cell at the pointer |
@
|
exit execution and return the value pointed by the last execution executed. |
All characters other than ><+-.,[]!?@ should be considered comments and ignored.
If no input environment array is given, the environment array is initially an array of a fixed dimension with all cells septed to zero . The initial dimension depends on interpreter implementation.
Return value
Brainfuck-ng always return the value of the cell pointed by the last instruction executed.
bfng - The brainfuck-ng interpreter
repositories
usage
brainfuck-ng v0.1 USAGE: bfng [options] [file] valid options: -i --shell interactive (shell mode) -h --help show this help -v --version prints brainfuck-ng version number -s --stdin read bf prog from stdin -d 'datum' --data set environment-array -o --out print env-array to stdout after computation -p --print same as -o but with newline added. -r --reversefuck switch 'ReverseFuck' mode on. -m size --size set the size (in bytes) of environment array (default is 32K). -x 'prog' --exec gets & execute bf prog -c --cin gets environment-array from stdin -b file --xfile gets bf prog from file -a file --dfile gets environment-array from file
interpreter's interactive commands
in shell interactive mode you can give brainfuck-ng interpreter the following command:
:q quit interpreter
:h print help summary
:ks (yes|no)
:ks print the keep state variable. :ks yes or :ks no set the
keep state variable. The keep state variable can retain the
value of the environment-array between line input.
:p print the environment-array to stdout (added with \n endline).
:r (yes|no)
enable/disable/show reverse-fuck mode.
:set datum
set the environment-array to datum (and set :ks yes)
:z print the last return value to stdout
ReverseFuck mode
In the 'ReverseFuck' mode all commands are switched to their semantic opposite. Here is an overview:
Instructions: - Increments the current cell (under the pointer). + Decrements the current cell (under the pointer). > Decrements pointer. < Increments pointer. . Inputs a character to current cell. , Outputs a character from current cell. ] While the current cell value is not zero, do stuff inside ] and [ braces [ End while. ! input integer at current cell. ? output integer from current cell. @ exit program returning current cel value( the only command not changed).
You can switch to ReverseFuck mode by adding the -r or --reversefuck option to the bfng interpreter.
Examples
Hello, World!
++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.
This is a slightly more complex variant that often triggers interpreter bugs
>++++++++[<+++++++++>-]<.>>+>+>++>[-]+<[>[->+<<++++>]<<]>.+++++++..+++.> >+++++++.<<<[[-]<[-]>]<+++++++++++++++.>>.+++.------.--------.>>+.>++++.
bfng - The brainfuck-ng interpreter
- get the return value:
% echo "+++"|bfng -s % echo $? 3 #(the putput)
- give an environment and get the result:
% echo "foobar"|bfng -c -x'+' -o goobar #(the output) or % echo "+"|bfng -d'foobar' -p goobar #(the output)
- give an environment and a program from files:
% bfng -b program.bf -a env.data
- simply execute a program
% bfng HelloWorld.bf
- get input and give output from bf program:
% bfng -x '?+++!' 35 #(user keyboard input) 38 #(program output) % echo $? 38 #(output)
- enter interactive shell mode:
% bfng -i