brauliovm.github.io/js/services/programs.js

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//import TuringMachine from '../TuringMachine/index.js';


class Program {
	constructor(name, link, rules){
		this.name = name;
		this.link = link;
		this.machine = new TuringMachine(0, -1); // Q0 and HALT

		for(let rule of rules){
			this.machine.addRule(...rule);
		}
	} 
}

// transform Q[0] ... Q[1] and HALT constants into numbers
const 
	HALT = "HALT",
	STATE_PREFIX = "Q",
	RIGHT = "RIGHT",
	LEFT = "LEFT";

/* TSON == TuringSon, similar to JSON but with state names and stuff */
function getProgramsFromTson(tson){
	var machines_data = JSON.parse(transformToValidJson(tson));
	let programs = [];

	for(let machine_data of machines_data){
		programs.push(new Program(machine_data.name, machine_data.link, machine_data.rules));
	}

	return programs;
}
		
function transformToValidJson(text){
	text = text.split(HALT).join(-1);	// we assign HALT state to -1 
	text = text.split(RIGHT).join(1);
	text = text.split(LEFT).join(-1);

	let i = 0,
		currentState = STATE_PREFIX + i;

	while (text.indexOf(currentState) != -1){
		text = text.split(currentState).join(i);
		i++;
		currentState = STATE_PREFIX + i;
	}

	return text;
}

const PROGRAMS_URL = "/data/programs.tson";

export function getPrograms(){
	return fetch(PROGRAMS_URL).then(
			(response) => 
			response.text()
		).then(getProgramsFromTson);
}