156 lines
3.3 KiB
JavaScript
156 lines
3.3 KiB
JavaScript
var step_delay = 0;
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var port = 35209;
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var verbose = false;
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var printtape = false;
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// TODO: Do better than this?
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var trans_done = 0;
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var tape_done = 0;
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var head_loc = 0;
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var state = 0;
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var tape = ["_"];
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var transitions = {};
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var steps = 0;
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var pretty_tape = "";
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var fs = require('fs');
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var readline = require('readline');
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var express = require('express');
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var web = express();
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var transitionReader = readline.createInterface({
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input: fs.createReadStream('transitions')
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});
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var tapeReader = readline.createInterface({
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input: fs.createReadStream('tape')
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});
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transitionReader.on('line', function(line) {
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if (verbose) console.log(line);
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var file_transitions = line.split(/[\s,]/);
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if (!transitions[file_transitions[0]]) transitions[file_transitions[0]] = {};
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transitions[file_transitions[0]][file_transitions[1]] = {
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to:file_transitions[2],
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write:file_transitions[3],
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move:file_transitions[4]
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};
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});
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transitionReader.on('close', function() {
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console.log("Done reading TRANSITIONS!");
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trans_done = 1;
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});
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tapeReader.on('line', function(line) {
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var symbols = line;
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for (var i = 0; i < symbols.length; i++) {
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if (symbols[i] == " ") {
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tape[i+1] = "_";
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} else {
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tape[i+1] = symbols[i];
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}
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}
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});
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tapeReader.on('close', function() {
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console.log("Done reading TAPE!");
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tape_done = 1;
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});
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var step = function() {
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steps++;
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if (verbose) console.log("START step");
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if (tape[head_loc] == undefined) {
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tape[head_loc] = "_";
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}
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if (verbose) {
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pretty_tape = "";
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for (i = 0; i < tape.length; i++) {
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if (i == head_loc) pretty_tape = pretty_tape + "[";
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pretty_tape = pretty_tape + tape[i];
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if (i == head_loc) pretty_tape = pretty_tape + "]";
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}
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}
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if (verbose) console.log(pretty_tape);
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var cur_symbol = tape[head_loc];
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if (verbose) console.log("Symbol: %s | State: %s",cur_symbol,state);
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// Get the transition based on the current state and symbol
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var transition = transitions[state][cur_symbol];
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// Write to tape
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tape[head_loc] = transition.write;
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// Change state
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state = transition.to;
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// Move head
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if (transition.move == 'R') {
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head_loc++;
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} else if (transition.move == 'L') {
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head_loc--;
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}
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if (verbose) console.log("State: %s | Head: %s",state,head_loc)
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// Throw error if head was moved over the left edge of the tape
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if (head_loc == -1) {
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throw "head_loc error";
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}
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if (printtape) console.log("Tape %s",tape);
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if (verbose) console.log("END step!");
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setTimeout(step, step_delay);
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}
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var prestep = function() {
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// Check if the transitions and tape have been initialised
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if (trans_done == 1 && tape_done == 1) {
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if (verbose) console.log(transitions);
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if (verbose) console.log(tape);
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console.log("Ready! Stepping!");
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step();
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} else {
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console.log("Not ready! Waiting 100 ms...");
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setTimeout(prestep, 100);
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}
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}
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prestep();
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// Set up web server
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web.get('', function(req, res) {
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var webtape = "";
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for (i = 0; i < tape.length; i++) {
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if (i == head_loc) webtape = webtape + "[";
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webtape = webtape + tape[i];
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if (i == head_loc) webtape = webtape + "]";
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}
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res.send(webtape + "<br><br>" + "Steps: " + steps);
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});
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web.listen(port, function () {
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console.log("Server listening on port %s",port);
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});
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