Created
May 18, 2017 09:20
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Brainfuck interpreter written in Javascript
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title></title> | |
| <style media="screen"> | |
| body * { | |
| margin: 10px; | |
| padding: 0; | |
| display: block; | |
| box-sizing: border-box; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <textarea id="input" rows="8" cols="80"></textarea> | |
| <textarea id="stdinput" rows="8" cols="80"></textarea> | |
| <button type="button" name="execute" id="execute">Execute</button> | |
| <textarea id="output" rows="8" cols="80"></textarea> | |
| <script charset="utf-8"> | |
| const input = document.getElementById("input"); | |
| const stdinput = document.getElementById("stdinput"); | |
| const output = document.getElementById("output"); | |
| const execute = document.getElementById("execute"); | |
| execute.onclick = () => { | |
| output.value = ""; | |
| const program = input.value.split(""); | |
| const stdin = stdinput.value.split(""); | |
| const runner = new Brainfuck(program, () => { | |
| return (stdin.shift() || "0").charCodeAt(0); | |
| }, (byte) => { | |
| output.value += byte; | |
| }); | |
| runner.execute(); | |
| } | |
| class Brainfuck { | |
| constructor(program, stdin, stdout) { | |
| this.program = program; | |
| this.stdin = stdin; | |
| this.stdout = stdout; | |
| this.cells = new Array(30000).fill(0); // memory cells | |
| this.ptr = 0; // memory pointer | |
| this.pc = 0; // program counter | |
| } | |
| /* | |
| Begin executing the program | |
| */ | |
| execute() { | |
| // Execute while we're at a legal position | |
| while (this.pc >= 0 && this.pc < this.program.length) { | |
| const op = this.program[this.pc]; | |
| switch (op) { | |
| case ">": { | |
| this.ptr++; | |
| break; | |
| } | |
| case "<": { | |
| this.ptr--; | |
| break; | |
| } | |
| case "+": { | |
| this.cells[this.ptr]++; | |
| break; | |
| } | |
| case "-": { | |
| this.cells[this.ptr]--; | |
| break; | |
| } | |
| case ".": | |
| this.stdout(String.fromCharCode(this.cells[this.ptr])); | |
| break; | |
| case ",": | |
| let input = this.stdin(); | |
| this.cells[this.ptr] = input; | |
| break; | |
| case "[": | |
| case "]": | |
| case " ": break; | |
| case "\n": break; | |
| case "\r": break; | |
| default: | |
| this.stdout("Error: Unexpected char: " + op); | |
| this.pc = -2; | |
| } | |
| // Increment the program counter | |
| this.pc++; | |
| } | |
| } | |
| } | |
| </script> | |
| </body> | |
| </html> |
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Still missing loops