Execute Brain****

Execute Brain****
You are encouraged to solve this task according to the task description, using any language you may know.

Execute Brain**** is an implementation of Brainf***. Other implementations of Brainf***.

RCBF is a set of Brainf*** compilers and interpreters written for Rosetta Code in a variety of languages. Below are links to each of the versions of RCBF.

An implementation need only properly implement the '[', ']', '+', '-', '<', '>', ',', and '.' instructions. Any cell size is allowed, EOF support is optional, as is whether you have bounded or unbounded memory.

ALGOL 68

Implementation in Algol 68.

Ada

Implementation in Ada.

AutoHotkey

Implementation in AutoHotkey.

BASIC

Implementation in BASIC (QuickBasic dialect).

C

Implementation in C.

C++

Implementation in C++.

Clojure

<lang clojure>(ns brainfuck)

(def *input*)

(def *output*)

(defstruct data :ptr :cells)

(defn inc-ptr [next-cmd]

 (fn [data]
   (next-cmd (assoc data :ptr (inc (:ptr data))))))

(defn dec-ptr [next-cmd]

 (fn [data]
   (next-cmd (assoc data :ptr (dec (:ptr data))))))

(defn inc-cell [next-cmd]

 (fn [data]
   (let [ptr (:ptr data)
         cells (:cells data)]
     (next-cmd (assoc data :cells (assoc cells ptr (inc (get cells ptr 0))))))))

(defn dec-cell [next-cmd]

 (fn [data]
   (let [ptr (:ptr data)
         cells (:cells data)]
     (next-cmd (assoc data :cells (assoc cells ptr (dec (get cells ptr 0))))))))

(defn output-cell [next-cmd]

 (fn [data]
   (set! *output* (conj *output* (get (:cells data) (:ptr data) 0)))
   (next-cmd data)))

(defn input-cell [next-cmd]

 (fn [data]
   (let [[input & rest-input] *input*]
     (set! *input* rest-input)
     (next-cmd (assoc data :cells (assoc (:cells data) (:ptr data) input))))))

(defn if-loop [next-cmd loop-cmd]

 (fn [data]
   (next-cmd (loop [d data]
               (if (zero? (get (:cells d) (:ptr d) 0))
                 d
                 (recur (loop-cmd d)))))))

(defn terminate [data] data)

(defn split-cmds [cmds]

 (letfn [(split [[cmd & rest-cmds] loop-cmds]
                (when (nil? cmd) (throw (Exception. "invalid commands: missing ]")))
                (case cmd
                      \[ (let [[c l] (split-cmds rest-cmds)]
                           (split c (str loop-cmds "[" l "]")))
                      \] [(apply str rest-cmds) loop-cmds]
                      (split rest-cmds (str loop-cmds cmd))))]
   (split cmds "")))

(defn compile-cmds cmd & rest-cmds

 (if (nil? cmd)
   terminate
   (case cmd
         \> (inc-ptr (compile-cmds rest-cmds))
         \< (dec-ptr (compile-cmds rest-cmds))
         \+ (inc-cell (compile-cmds rest-cmds))
         \- (dec-cell (compile-cmds rest-cmds))
         \. (output-cell (compile-cmds rest-cmds))
         \, (input-cell (compile-cmds rest-cmds))
         \[ (let [[cmds loop-cmds] (split-cmds rest-cmds)]
              (if-loop (compile-cmds cmds) (compile-cmds loop-cmds)))
         \] (throw (Exception. "invalid commands: missing ["))
         (compile-cmds rest-cmds))))

(defn compile-and-run [cmds input]

 (binding [*input* input *output* []]
   (let [compiled-cmds (compile-cmds cmds)]
    (println (compiled-cmds (struct data 0 {}))))
   (println *output*)
   (println (apply str (map char *output*)))))

</lang> <lang clojure>brainfuck> (compile-and-run "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>." []) {:ptr 4, :cells {4 10, 3 33, 2 100, 1 87, 0 0}} [72 101 108 108 111 32 87 111 114 108 100 33 10] Hello World!

nil </lang>

Common Lisp

Implementation in Common Lisp.

D

Implementation in D.

Alternative version, simpler and faster. <lang d>import core.stdc.stdio: getc, putchar, stdin, EOF; import core.stdc.stdlib: exit;

void brainfuckRun(const string code) {

   static pure int[int] matchBraces(const string code)
       out(result) {
           foreach (k, v; result) {
               assert(k >=0 && k < code.length);
               assert(v >=0 && v < code.length);
               assert(v in result);
           }
       } body {
           int[int] loops;
           int[] loopStack;

           foreach (i, instruction; code) {
               if (instruction == '[')
                   loopStack ~= i;
               else if (instruction == ']') {
                   assert(loopStack.length);
                   loops[i] = loopStack[$ - 1];
                   loopStack.length -= 1;
                   loops[loops[i]] = i;
               }
           }

           assert(!loopStack.length);
           return loops;
       }

   static void runCode(const string code, const int[int] loops) {
       enum char empty = '\0';
       char[30_000] tape = empty;
       int cell, index;

       while (index < cast(int)code.length) {
           immutable int instruction = code[index];

           switch (instruction) {
               case '>': cell++; assert(cell < tape.length); break;
               case '<': cell--; assert(cell >= 0); break;
               case '+': tape[cell]++; break;
               case '-': tape[cell]--; break;
               case '.': putchar(tape[cell]); break;
               case ',':
                   int c = getc(stdin);
                   if (c == EOF)
                       exit(1);
                   tape[cell] = cast(char)c;
                   break;
               case '[':
                   if (tape[cell] == empty)
                       index = loops[index];
                   break;
               case ']':
                   if (tape[cell] != empty)
                       index = loops[index];
                   break;
               default: break;
           }

           index++;
       }
   }

   int[int] loops = matchBraces(code);
   runCode(code, loops);

}

void main() {

   brainfuckRun("++++++++++[>+++++++>++++++++++>+++>+<<<<-]
     >++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.");

}</lang> Faster partially compile-time version (code generated at compile-time, run at run time): <lang d>import core.stdc.stdio: getc, putchar, stdin, EOF; import core.stdc.stdlib: exit;

string ctbf(string code) {

   string r;

   foreach (c; code)
       switch (c) {
           case '>': r ~= "i++; assert(i < m.length);"; break;
           case '<': r ~= "i--; assert(i >= 0);"; break;
           case '+': r ~= "m[i]++;"; break;
           case '-': r ~= "m[i]--;"; break;
           case '[': r ~= "while (m[i]) {"; break;
           case ']': r ~= "}"; break;
           case '.': r ~= "putchar(m[i]);"; break;
           case ',':
               r ~= "int d = getc(stdin);
                     if (d == EOF) exit(1);
                     tape[cell] = cast(char)d;";
               break;
           default: break;
       }

   return r;

}

void main() {

   enum char empty = '\0';
   char[30_000] m = empty;
   size_t i;
   mixin(ctbf("++++++++++[>+++++++>++++++++++>+++>+<<<<-]
              >++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."));

}</lang>

E

Implementation in E.

Erlang

Implementation in Erlang.

Forth

Implementation in Forth.

F#

Implementation in F#.

GAP

<lang gap># Here . and , print and read an integer, not a character Brainfuck := function(prog)

 local pointer, stack, leftcells, rightcells, instr, stackptr, len,
   output, input, jump, i, j, set, get;
 input := InputTextUser();
 output := OutputTextUser();
 instr := 1;
 pointer := 0;
 leftcells := [ ];
 rightcells := [ ];
 stack := [ ];
 stackptr := 0;
 len := Length(prog);
 jump := [ ];

 get := function()
   local p;
   if pointer >= 0 then
     p := pointer + 1;
     if IsBound(rightcells[p]) then
       return rightcells[p];
     else
       return 0;
     fi;
   else
     p := -pointer;
     if IsBound(leftcells[p]) then
       return leftcells[p];
     else
       return 0;
     fi;
   fi;
 end;
 
 set := function(value)
   local p;
   if pointer >= 0 then
     p := pointer + 1;
     if value = 0 then
       Unbind(rightcells[p]);
     else
       rightcells[p] := value;
     fi;
   else
     p := -pointer;
     if value = 0 then
       Unbind(leftcells[p]);
     else
       leftcells[p] := value;
     fi;
   fi;
 end;
 
 # find jumps for faster execution
 for i in [1 .. len] do
   if prog[i] = '[' then
     stackptr := stackptr + 1;
     stack[stackptr] := i;
   elif prog[i] = ']' then
     j := stack[stackptr];
     stackptr := stackptr - 1;
     jump[i] := j;
     jump[j] := i;
   fi;
 od;

 while instr <= len do
   c := prog[instr];
   if c = '<' then
     pointer := pointer - 1;
   elif c = '>' then
     pointer := pointer + 1;
   elif c = '+' then
     set(get() + 1);
   elif c = '-' then
     set(get() - 1);
   elif c = '.' then
     WriteLine(output, String(get()));
   elif c = ',' then
     set(Int(Chomp(ReadLine(input))));
   elif c = '[' then
     if get() = 0 then
       instr := jump[instr];
     fi;
   elif c = ']' then
     if get() <> 0 then
       instr := jump[instr];
     fi;
   fi;
   instr := instr + 1;
 od;
 CloseStream(input);
 CloseStream(output);
 # for debugging purposes, return last state
 return [leftcells, rightcells, pointer];

end;

1. An addition

Brainfuck("+++.<+++++.[->+<]>.");

1. 3
2. 5
3. 8</lang>

Haskell

Implementation in Haskell.

Icon and Unicon

Works with: Unicon

Implementation in Icon.

J

Implementation in J.

Java

Implementation in Java.

JavaScript

Implementation in JavaScript.

Lua

Implementation in Lua.

Modula-3

Implementation in Modula-3.

OCaml

Implementation in OCaml.

Perl

Implementation in Perl.

Perl 6

Implementation in Perl 6.

PicoLisp

This solution uses a doubly-linked list for the cell space. That list consists of a single cell initially, and grows automatically in both directions. The value in each cell is unlimited. <lang PicoLisp>(off "Program")

(de compile (File)

  (let Stack NIL
     (setq "Program"
        (make
           (in File
              (while (char)
                 (case @
                    (">"
                       (link
                          '(setq Data
                             (or
                                (cddr Data)
                                (con (cdr Data) (cons 0 (cons Data))) ) ) ) )
                    ("<"
                       (link
                          '(setq Data
                             (or
                                (cadr Data)
                                (set (cdr Data) (cons 0 (cons NIL Data))) ) ) ) )
                    ("+" (link '(inc Data)))
                    ("-" (link '(dec Data)))
                    ("." (link '(prin (char (car Data)))))
                    ("," (link '(set Data (char (read)))))
                    ("["
                       (link
                          '(setq Code
                             ((if (=0 (car Data)) cdar cdr) Code) ) )
                       (push 'Stack (chain (cons))) )
                    ("]"
                       (unless Stack
                          (quit "Unbalanced ']'") )
                       (link
                          '(setq Code
                             ((if (n0 (car Data)) cdar cdr) Code) ) )
                       (let (There (pop 'Stack)  Here (cons There))
                          (chain (set There Here)) ) ) ) ) ) ) )
     (when Stack
        (quit "Unbalanced '['") ) ) )

(de execute ()

  (let Data (cons 0 (cons))              # Create initial cell
     (for (Code "Program"  Code)         # Run program
        (eval (pop 'Code)) )
     (while (cadr Data)                  # Find beginning of data
        (setq Data @) )
     (filter prog Data '(T NIL .)) ) )   # Return data space</lang>

Output:

: (compile "hello.bf")
-> NIL

: (execute)
Goodbye, World!
-> (0 10 33 44 71 87 98 100 114 121)

Alternative solution

# This implements a BrainFuck *interpreter* similar to the "official" one.
# It has 30000 unsigned 8-bit cells with wrapping, going off the bounds
# of the memory results in an error.
(de bf (Prg)
   (let (P Prg S NIL D (need 30000 0) Dp D F T )
      (while P
         (case (car P)
            ("+" (if F (set Dp (% (inc (car Dp) 256)))))
            ("-" (if F (set Dp (% (dec (car Dp) 256)))))
            (">" (if F (setq Dp (cdr Dp))))
            ("<" (if F (setq Dp (prior Dp D))))
            ("." (if F (prin (char (car Dp)))))
            ("," (if F (set Dp (char (read)))))
            ("["
             (push 'S (if F (prior P Prg)))
             (setq F (n0 (car Dp))) )
            ("]"
             (and (setq F (pop 'S))
                (n0 (car Dp))
                (setq P F) ) ) )
         (pop 'P) ) ) )

# A little "Hello world! test of the interpreter."
(bf (chop ">+++++++++[<++++++++>-]<.>+++++++[<++++>-]<+.+++++++..+++.[-]
>++++++++[<++++>-] <.>+++++++++++[<++++++++>-]<-.--------.+++.------.---
-----.[-]>++++++++[<++++>- ]<+.[-]++++++++++." ) )
(bye)

PureBasic

Implementation in PureBasic

Python

Implementation in Python.

Ruby

Implementation in Ruby.

Standard ML

Implementation in Standard ML.

TI-83 BASIC

Implementation in TI-83 BASIC.

TI-89 BASIC

Implementation in TI-89 Basic.

Tcl

Implementation in Tcl.