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yfgeek/brainfuck.js

Created November 30, 2017 14:33
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  1. yfgeek created this gist Nov 30, 2017.
    106 changes: 106 additions & 0 deletions brainfuck.js
    View file
    Original file line number Diff line number Diff line change
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    /**
    * Brainfuck Interpreter
    * author: yfgeek
    * https://github.com/yfgeek
    */
    'use strict';

    class Interpreter{
    constructor(code,input) {
    this.code = code.trim().replace(/ /g, "").replace(/(\r\n|\n|\r)/gm,"").split("");
    this.input = input || [];
    this.pointer = 0;
    this.codePointer = 0 ;
    this.dataset = [];
    this.bracketStack = [];
    this.output = [];
    }

    operation(str){

    switch(str){
    case '+': {
    this.dataset[this.pointer] = this.dataset[this.pointer] || 0;
    ++this.dataset[this.pointer];
    break;
    }

    case '-': {
    this.dataset[this.pointer] = this.dataset[this.pointer] || 0;
    --this.dataset[this.pointer];
    break;
    }

    case '<':{
    this.pointer = --this.pointer<0 ? 0: this.pointer;
    break;
    }

    case '>': {
    this.pointer++;
    break;
    }

    case '.':{
    this.output.push(String.fromCharCode(this.dataset[this.pointer]));
    break;
    }

    case ',':{
    let c = this.input.shift();
    if (typeof c === "string") {
    this.dataset[this.pointer] = c.charCodeAt(0);
    }
    break;
    }

    case '[': {
    this.leftBracket();
    break;
    }

    case ']': {
    this.rightBracket();
    break;
    }
    }

    };

    leftBracket(){
    let openBrackets = 1;
    if (this.dataset[this.pointer]) {
    this.bracketStack.push(this.codePointer);
    } else {
    while (openBrackets && this.code[++this.codePointer]) {
    if (this.code[this.codePointer] === ']') {
    openBrackets--;
    } else if (this.code[this.codePointer] === '[') {
    openBrackets++;
    }
    }
    }
    }

    rightBracket(){
    this.codePointer = this.bracketStack.pop() - 1;
    }

    run(){
    let list = ['+','-','<','>','.',',','[',']'];
    do{
    let c = this.code[this.codePointer];
    if(list.indexOf(c) >= 0) this.operation(c);
    }while(++this.codePointer < this.code.length);
    return this.output;
    }

    toString(){
    return this.run().join('');
    }

    }

    let code = '++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.';
    let i = new Interpreter(code,[]);
    console.log(i.toString());