index.html

@@ -23,6 +23,9 @@
         <br />
         📖 This page hosts strictly static content.
         <br />
+        🐙 Obviously my GitHub is at
+        <a href="https://github.com/Simponic">/simponic</a>.
+        <br />
         🔔 My "real website" is at
         <a href="https://simponic.xyz">simponic.xyz</a>.
       </h3>
@@ -35,12 +38,23 @@
           <div class="project-body">
             <h1>Euler Golf 2</h1>
             <p>
-              A puzzle game (with BFS solver) to explore rotations in the complex
-              plane.
+              A puzzle game (with BFS solver) to explore rotations in the
+              complex plane.
             </p>
           </div>
         </a>
 
+        <a class="project" href="/turing-machine/">
+          <div class="project-logo-container">
+            <i class="fa-solid fa-tape"></i>
+          </div>
+
+          <div class="project-body">
+            <h1>Simponic's State System</h1>
+            <p>A Turing Machine simulator specific to CS5000.</p>
+          </div>
+        </a>
+
         <a class="project" href="/julia/">
           <div class="project-logo-container">
             <i class="fa-solid fa-square-root-variable"></i>
@@ -77,8 +91,8 @@
           <div class="project-body">
             <h1>The A-maze-ing Maize Maze</h1>
             <p>
-              A Randomized Kruskal's Maze game with (more) BFS. You play
-              as a 🌽corn stalk trying to become 🍿popcorn.
+              A Randomized Kruskal's Maze game with (more) BFS. You play as a
+              🌽corn stalk trying to become 🍿popcorn.
             </p>
           </div>
         </a>
@@ -90,9 +104,7 @@
 
           <div class="project-body">
             <h1>Centipede</h1>
-            <p>
-              Boring remake of the classic arcade game.
-            </p>
+            <p>Boring remake of the classic arcade game.</p>
           </div>
         </a>
 

julia/julia.js

@@ -3,7 +3,7 @@ const MAX_ZOOM = 4;
 const C_THRESHOLD = Math.sqrt(2)/2;
 const SLIDER_DIV = 2000*C_THRESHOLD;
 
-const gpu = new GPU();
+const gpu = new GPUX();
 const buildRender = (width, height) => gpu.createKernel(function (maxIterations, cr, ci, centerX, centerY, zoom, colorMultipliers) {
   let zx = (this.output.x / this.output.y) * (centerX + (4 * this.thread.x / this.output.x - 2) * (zoom / 4));
   let zy = centerY + (4 * this.thread.y / this.output.y - 2) * (zoom / 4);

turing-machine/codemirror/codemirror.css

@@ -0,0 +1,488 @@
+/* BASICS */
+
+.CodeMirror {
+  /* Set height, width, borders, and global font properties here */
+  font-family: monospace !important;
+  height: 300px;
+  color: black;
+  direction: ltr;
+}
+
+/* PADDING */
+
+.CodeMirror-lines {
+  padding: 4px 0; /* Vertical padding around content */
+}
+.CodeMirror pre.CodeMirror-line,
+.CodeMirror pre.CodeMirror-line-like {
+  padding: 0 4px; /* Horizontal padding of content */
+}
+
+.CodeMirror-scrollbar-filler,
+.CodeMirror-gutter-filler {
+  background-color: white; /* The little square between H and V scrollbars */
+}
+
+/* GUTTER */
+
+.CodeMirror-gutters {
+  border-right: 1px solid #ddd;
+  background-color: #f7f7f7;
+  white-space: nowrap;
+}
+.CodeMirror-linenumbers {
+}
+.CodeMirror-linenumber {
+  padding: 0 3px 0 5px;
+  min-width: 20px;
+  text-align: right;
+  color: #999;
+  white-space: nowrap;
+}
+
+.CodeMirror-guttermarker {
+  color: black;
+}
+.CodeMirror-guttermarker-subtle {
+  color: #999;
+}
+
+/* CURSOR */
+
+.CodeMirror-cursor {
+  border-left: 1px solid black;
+  border-right: none;
+  width: 0;
+}
+/* Shown when moving in bi-directional text */
+.CodeMirror div.CodeMirror-secondarycursor {
+  border-left: 1px solid silver;
+}
+.cm-fat-cursor .CodeMirror-cursor {
+  width: auto;
+  border: 0 !important;
+  background: #7e7;
+}
+.cm-fat-cursor div.CodeMirror-cursors {
+  z-index: 1;
+}
+.cm-fat-cursor .CodeMirror-line::selection,
+.cm-fat-cursor .CodeMirror-line > span::selection,
+.cm-fat-cursor .CodeMirror-line > span > span::selection {
+  background: transparent;
+}
+.cm-fat-cursor .CodeMirror-line::-moz-selection,
+.cm-fat-cursor .CodeMirror-line > span::-moz-selection,
+.cm-fat-cursor .CodeMirror-line > span > span::-moz-selection {
+  background: transparent;
+}
+.cm-fat-cursor {
+  caret-color: transparent;
+}
+@-moz-keyframes blink {
+  0% {
+  }
+  50% {
+    background-color: transparent;
+  }
+  100% {
+  }
+}
+@-webkit-keyframes blink {
+  0% {
+  }
+  50% {
+    background-color: transparent;
+  }
+  100% {
+  }
+}
+@keyframes blink {
+  0% {
+  }
+  50% {
+    background-color: transparent;
+  }
+  100% {
+  }
+}
+
+/* Can style cursor different in overwrite (non-insert) mode */
+.CodeMirror-overwrite .CodeMirror-cursor {
+}
+
+.cm-tab {
+  display: inline-block;
+  text-decoration: inherit;
+}
+
+.CodeMirror-rulers {
+  position: absolute;
+  left: 0;
+  right: 0;
+  top: -50px;
+  bottom: 0;
+  overflow: hidden;
+}
+.CodeMirror-ruler {
+  border-left: 1px solid #ccc;
+  top: 0;
+  bottom: 0;
+  position: absolute;
+}
+
+/* DEFAULT THEME */
+
+.cm-s-default .cm-header {
+  color: blue;
+}
+.cm-s-default .cm-quote {
+  color: #090;
+}
+.cm-negative {
+  color: #d44;
+}
+.cm-positive {
+  color: #292;
+}
+.cm-header,
+.cm-strong {
+  font-weight: bold;
+}
+.cm-em {
+  font-style: italic;
+}
+.cm-link {
+  text-decoration: underline;
+}
+.cm-strikethrough {
+  text-decoration: line-through;
+}
+
+.cm-s-default .cm-keyword {
+  color: #708;
+}
+.cm-s-default .cm-atom {
+  color: #219;
+}
+.cm-s-default .cm-number {
+  color: #164;
+}
+.cm-s-default .cm-def {
+  color: #00f;
+}
+.cm-s-default .cm-variable,
+.cm-s-default .cm-punctuation,
+.cm-s-default .cm-property,
+.cm-s-default .cm-operator {
+}
+.cm-s-default .cm-variable-2 {
+  color: #05a;
+}
+.cm-s-default .cm-variable-3,
+.cm-s-default .cm-type {
+  color: #085;
+}
+.cm-s-default .cm-comment {
+  color: #a50;
+}
+.cm-s-default .cm-string {
+  color: #a11;
+}
+.cm-s-default .cm-string-2 {
+  color: #f50;
+}
+.cm-s-default .cm-meta {
+  color: #555;
+}
+.cm-s-default .cm-qualifier {
+  color: #555;
+}
+.cm-s-default .cm-builtin {
+  color: #30a;
+}
+.cm-s-default .cm-bracket {
+  color: #997;
+}
+.cm-s-default .cm-tag {
+  color: #170;
+}
+.cm-s-default .cm-attribute {
+  color: #00c;
+}
+.cm-s-default .cm-hr {
+  color: #999;
+}
+.cm-s-default .cm-link {
+  color: #00c;
+}
+
+.cm-s-default .cm-error {
+  color: #f00;
+}
+.cm-invalidchar {
+  color: #f00;
+}
+
+.CodeMirror-composing {
+  border-bottom: 2px solid;
+}
+
+/* Default styles for common addons */
+
+div.CodeMirror span.CodeMirror-matchingbracket {
+  color: #0b0;
+}
+div.CodeMirror span.CodeMirror-nonmatchingbracket {
+  color: #a22;
+}
+.CodeMirror-matchingtag {
+  background: rgba(255, 150, 0, 0.3);
+}
+.CodeMirror-activeline-background {
+  background: #e8f2ff;
+}
+
+/* STOP */
+
+/* The rest of this file contains styles related to the mechanics of
+   the editor. You probably shouldn't touch them. */
+
+.CodeMirror {
+  position: relative;
+  overflow: hidden;
+  background: white;
+}
+
+.CodeMirror-scroll {
+  overflow: scroll !important; /* Things will break if this is overridden */
+  /* 50px is the magic margin used to hide the element's real scrollbars */
+  /* See overflow: hidden in .CodeMirror */
+  margin-bottom: -50px;
+  margin-right: -50px;
+  padding-bottom: 50px;
+  height: 100%;
+  outline: none; /* Prevent dragging from highlighting the element */
+  position: relative;
+  z-index: 0;
+}
+.CodeMirror-sizer {
+  position: relative;
+  border-right: 50px solid transparent;
+}
+
+/* The fake, visible scrollbars. Used to force redraw during scrolling
+   before actual scrolling happens, thus preventing shaking and
+   flickering artifacts. */
+.CodeMirror-vscrollbar,
+.CodeMirror-hscrollbar,
+.CodeMirror-scrollbar-filler,
+.CodeMirror-gutter-filler {
+  position: absolute;
+  z-index: 6;
+  display: none;
+  outline: none;
+}
+.CodeMirror-vscrollbar {
+  right: 0;
+  top: 0;
+  overflow-x: hidden;
+  overflow-y: scroll;
+}
+.CodeMirror-hscrollbar {
+  bottom: 0;
+  left: 0;
+  overflow-y: hidden;
+  overflow-x: scroll;
+}
+.CodeMirror-scrollbar-filler {
+  right: 0;
+  bottom: 0;
+}
+.CodeMirror-gutter-filler {
+  left: 0;
+  bottom: 0;
+}
+
+.CodeMirror-gutters {
+  position: absolute;
+  left: 0;
+  top: 0;
+  min-height: 100%;
+  z-index: 3;
+}
+.CodeMirror-gutter {
+  white-space: normal;
+  height: 100%;
+  display: inline-block;
+  vertical-align: top;
+  margin-bottom: -50px;
+}
+.CodeMirror-gutter-wrapper {
+  position: absolute;
+  z-index: 4;
+  background: none !important;
+  border: none !important;
+}
+.CodeMirror-gutter-background {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  z-index: 4;
+}
+.CodeMirror-gutter-elt {
+  position: absolute;
+  cursor: default;
+  z-index: 4;
+}
+.CodeMirror-gutter-wrapper ::selection {
+  background-color: transparent;
+}
+.CodeMirror-gutter-wrapper ::-moz-selection {
+  background-color: transparent;
+}
+
+.CodeMirror-lines {
+  cursor: text;
+  min-height: 1px; /* prevents collapsing before first draw */
+}
+.CodeMirror pre.CodeMirror-line,
+.CodeMirror pre.CodeMirror-line-like {
+  /* Reset some styles that the rest of the page might have set */
+  -moz-border-radius: 0;
+  -webkit-border-radius: 0;
+  border-radius: 0;
+  border-width: 0;
+  background: transparent;
+  font-family: inherit;
+  font-size: inherit;
+  margin: 0;
+  white-space: pre;
+  word-wrap: normal;
+  line-height: inherit;
+  color: inherit;
+  z-index: 2;
+  position: relative;
+  overflow: visible;
+  -webkit-tap-highlight-color: transparent;
+  -webkit-font-variant-ligatures: contextual;
+  font-variant-ligatures: contextual;
+}
+.CodeMirror-wrap pre.CodeMirror-line,
+.CodeMirror-wrap pre.CodeMirror-line-like {
+  word-wrap: break-word;
+  white-space: pre-wrap;
+  word-break: normal;
+}
+
+.CodeMirror-linebackground {
+  position: absolute;
+  left: 0;
+  right: 0;
+  top: 0;
+  bottom: 0;
+  z-index: 0;
+}
+
+.CodeMirror-linewidget {
+  position: relative;
+  z-index: 2;
+  padding: 0.1px; /* Force widget margins to stay inside of the container */
+}
+
+.CodeMirror-widget {
+}
+
+.CodeMirror-rtl pre {
+  direction: rtl;
+}
+
+.CodeMirror-code {
+  outline: none;
+}
+
+/* Force content-box sizing for the elements where we expect it */
+.CodeMirror-scroll,
+.CodeMirror-sizer,
+.CodeMirror-gutter,
+.CodeMirror-gutters,
+.CodeMirror-linenumber {
+  -moz-box-sizing: content-box;
+  box-sizing: content-box;
+}
+
+.CodeMirror-measure {
+  position: absolute;
+  width: 100%;
+  height: 0;
+  overflow: hidden;
+  visibility: hidden;
+}
+
+.CodeMirror-cursor {
+  position: absolute;
+  pointer-events: none;
+}
+.CodeMirror-measure pre {
+  position: static;
+}
+
+div.CodeMirror-cursors {
+  visibility: hidden;
+  position: relative;
+  z-index: 3;
+}
+div.CodeMirror-dragcursors {
+  visibility: visible;
+}
+
+.CodeMirror-focused div.CodeMirror-cursors {
+  visibility: visible;
+}
+
+.CodeMirror-selected {
+  background: #d9d9d9;
+}
+.CodeMirror-focused .CodeMirror-selected {
+  background: #d7d4f0;
+}
+.CodeMirror-crosshair {
+  cursor: crosshair;
+}
+.CodeMirror-line::selection,
+.CodeMirror-line > span::selection,
+.CodeMirror-line > span > span::selection {
+  background: #d7d4f0;
+}
+.CodeMirror-line::-moz-selection,
+.CodeMirror-line > span::-moz-selection,
+.CodeMirror-line > span > span::-moz-selection {
+  background: #d7d4f0;
+}
+
+.cm-searching {
+  background-color: #ffa;
+  background-color: rgba(255, 255, 0, 0.4);
+}
+
+/* Used to force a border model for a node */
+.cm-force-border {
+  padding-right: 0.1px;
+}
+
+@media print {
+  /* Hide the cursor when printing */
+  .CodeMirror div.CodeMirror-cursors {
+    visibility: hidden;
+  }
+}
+
+/* See issue #2901 */
+.cm-tab-wrap-hack:after {
+  content: "";
+}
+
+/* Help users use markselection to safely style text background */
+span.CodeMirror-selectedtext {
+  background: none;
+}

turing-machine/css/styles.css

@@ -0,0 +1,144 @@
+* {
+  margin: 0;
+}
+
+button {
+  background: #bbbbbb;
+  border: 1px solid white;
+  border-radius: 0.2rem;
+  padding: 0.3rem;
+  display: inline-block;
+  cursor: pointer;
+}
+
+button:hover {
+  background: #cccccc;
+}
+
+body {
+  font-family: "Trebuchet MS", sans-serif;
+  background-color: #aaaaaa;
+}
+
+.container {
+  display: flex;
+  width: 90%;
+  margin-left: auto;
+  margin-right: auto;
+  flex-direction: column;
+  gap: 1rem;
+
+  padding: 2rem;
+}
+
+.tape {
+  border-radius: 0.25rem;
+  box-shadow: 5px 5px 5px #666666;
+
+  display: flex;
+
+  padding: 1rem;
+
+  align-items: center;
+  gap: 1rem;
+
+  height: 5rem;
+  max-width: 100%;
+
+  border: 2px solid white;
+
+  overflow-x: scroll;
+  overflow-y: hidden;
+}
+
+.cell {
+  border-radius: 0.25rem;
+  box-shadow: 2px 2px 5px #666666;
+  background-color: #dddddd;
+  border: 2px solid white;
+
+  position: relative;
+  height: 80%;
+  transition: border 0.25s ease-in-out;
+  transition: background 0.25s ease-in-out;
+
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+  flex: 1;
+  gap: 0.2rem;
+
+  padding: 0.2rem;
+}
+
+.circle {
+  position: absolute;
+  bottom: -15px;
+  left: 50%;
+  transform: translateX(-50%);
+  width: 10px;
+  height: 10px;
+  background-color: wheat;
+  border-radius: 50%;
+  opacity: 0.001;
+  transition: opacity 0.25s ease-in-out;
+}
+
+.cell.reading .circle {
+  opacity: 1;
+}
+
+.reading {
+  border-color: wheat;
+  background-color: wheat;
+}
+
+.cell-input {
+  border: none;
+  border-radius: 0.25rem;
+
+  background-color: 1px solid #ccc;
+  width: 50px;
+  margin-left: 0.25rem;
+  margin-right: 0.25rem;
+
+  text-align: center;
+  font-size: 1rem;
+}
+
+.textarea-container {
+  display: flex;
+  flex-direction: column;
+  gap: 1rem;
+  box-shadow: 5px 5px 5px #666666;
+  border: 2px solid white;
+  border-radius: 0.25rem;
+  padding: 1rem;
+}
+
+textarea {
+  border-radius: 0.25rem;
+  height: 50vh;
+}
+
+.error {
+  color: red;
+}
+
+.success {
+  color: green;
+}
+
+.controls {
+  display: none;
+  gap: 1rem;
+  flex-direction: row;
+  justify-content: center;
+  align-items: stretch;
+}
+
+hr {
+  border-top: 2px solid black;
+  border-bottom: none;
+}

turing-machine/index.html

@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Turing Machine Simulator</title>
+    <link rel="stylesheet" type="text/css" href="css/styles.css" />
+    <link rel="stylesheet" type="text/css" href="codemirror/codemirror.css" />
+  </head>
+  <body>
+    <div class="container">
+      <h1>Simponic's State System</h1>
+      <p><i>Developed for Kulyukin's CS5000</i></p>
+      <hr />
+      <p id="turing_state">State: _</p>
+      <div id="tape" class="tape"></div>
+      <div class="controls" id="controls">
+        <button id="toggle_play">🔁 Begin</button>
+        <button id="next_step">Next Step</button>
+        <button id="reset">Reset</button><br />
+      </div>
+      <div class="textarea-container">
+        <ul>
+          <li>
+            must have some instruction quadruple with the start state "q0"
+          </li>
+          <li>all computations will fail unless they end on the state "f"</li>
+          <li>
+            instructions are delimited with line breaks and are in the form
+            <i
+              >"< from_state > < read_symbol > < L/R/write_symbol > < to_state
+              >"</i
+            >
+          </li>
+          <li>comments ("//") are ignored</li>
+        </ul>
+        <textarea id="instructions">
+// replaces 3 B's with "1"
+q0 B 1 q1
+q1 1 R q1
+q1 B 1 q2
+q2 1 R q2
+q2 B 1 f</textarea
+        >
+        <div>
+          <button id="compile">Compile</button
+          ><span style="margin-left: 0.5rem" id="compile_status"></span>
+        </div>
+        <div>
+          <button id="copy_state">Copy State</button>
+        </div>
+      </div>
+    </div>
+    <script src="codemirror/codemirror.js"></script>
+    <script src="js/observable.js"></script>
+    <script src="js/turing_machine.js"></script>
+    <script src="js/main.js"></script>
+  </body>
+</html>

turing-machine/js/main.js

@@ -0,0 +1,291 @@
+const TAPE_LEN = 150;
+const BLANK_VAL = "B";
+const SIMULATION_INTERVAL = 200;
+
+const MESSAGES = {
+  SET_CELL: "SET_CELL",
+  PAUSE: "PAUSE",
+  SIMULATE: "SIMULATE",
+  SET_READER: "SET_READER",
+  NEXT_STEP: "NEXT_STEP",
+  COMPILE: "COMPILE",
+  COMPILE_STATUS: "COMPILE_STATUS",
+  NEW_TURING_STATE: "NEW_TURING_STATE",
+};
+
+// -- the "real" code
+
+const state = new Observable();
+
+const inputCellId = (cellId) => `${cellId}-input`;
+
+const cell = (cellId, initValue = "B") => {
+  const cellDiv = document.createElement("div");
+  cellDiv.classList.add("cell");
+  cellDiv.id = cellId;
+
+  const readingHead = document.createElement("div");
+  readingHead.classList.add("circle");
+
+  const input = document.createElement("input");
+  const inputId = inputCellId(cellId);
+  input.classList.add("cell-input");
+  input.id = inputId;
+  input.value = initValue;
+
+  input.addEventListener("focusin", () =>
+    state.notify({ type: MESSAGES.PAUSE })
+  );
+  input.addEventListener("focusout", () =>
+    state.notify({ type: MESSAGES.SET_CELL, cell: cellId, value: input.value })
+  );
+
+  const msgListener = (msg) => {
+    if (msg.type == MESSAGES.SET_CELL && msg.cell == cellId) {
+      input.value = msg.value;
+    }
+    if (msg.type == MESSAGES.SET_READER) {
+      if (msg.cell == cellId) {
+        cellDiv.classList.add("reading");
+        cellDiv.scrollIntoView({
+          behavior: "smooth",
+        });
+      } else cellDiv.classList.remove("reading");
+    }
+    if (msg.type == MESSAGES.COMPILE) {
+      state.unsubscribe(msgListener);
+    }
+  };
+  state.subscribe(msgListener);
+
+  cellDiv.appendChild(input);
+  cellDiv.appendChild(readingHead);
+
+  return cellDiv;
+};
+
+const parseRules = (rules, beginState) => {
+  const quadruples = rules.split("\n");
+
+  const instructions = [];
+  quadruples.forEach((quadruple, line) => {
+    const commentLess = quadruple.replaceAll(/\/\/.*/g, "").trim();
+    if (!commentLess) {
+      return;
+    }
+
+    const items = commentLess
+      .split(" ")
+      .map((x) => x.trim())
+      .filter((x) => x);
+    if (items.length != 4) {
+      throw new Error(`Invalid instruction on line ${line + 1}`);
+    }
+    instructions.push(items);
+  });
+  if (!instructions.some(([fromState]) => fromState == beginState)) {
+    throw new Error(
+      `At least one instruction must begin from state: ${beginState}`
+    );
+  }
+  return instructions;
+};
+
+// -- a bit of some hacky ui code --
+
+const tapeEl = document.getElementById("tape");
+const compileButton = document.getElementById("compile");
+const resetButton = document.getElementById("reset");
+const controlsEl = document.getElementById("controls");
+const nextStepButton = document.getElementById("next_step");
+const togglePlayButton = document.getElementById("toggle_play");
+const compileStatusEl = document.getElementById("compile_status");
+const turingMachineStateEl = document.getElementById("turing_state");
+const copyStateButton = document.getElementById("copy_state");
+
+// init instructions from params
+const instructionsEl = document.getElementById("instructions");
+const editorEl = CodeMirror.fromTextArea(instructionsEl, {
+  lineNumbers: true,
+});
+const urlParams = new URLSearchParams(window.location.search);
+if (urlParams.get("instructions")) {
+  editorEl.setValue(atob(urlParams.get("instructions")));
+}
+
+[compileButton, resetButton].forEach((button) =>
+  button.addEventListener("click", () => {
+    state.notify({ type: MESSAGES.PAUSE });
+    state.notify({ type: MESSAGES.COMPILE, value: editorEl.getValue() });
+  })
+);
+
+nextStepButton.addEventListener("click", () => {
+  state.notify({ type: MESSAGES.PAUSE });
+  state.notify({ type: MESSAGES.NEXT_STEP });
+});
+
+// hackily copy the program state and put it in the clipboard
+copyStateButton.addEventListener("click", () => {
+  const start = Array(TAPE_LEN)
+    .fill(BLANK_VAL)
+    .map((blank, i) => document.getElementById(inputCellId(i))?.value ?? blank)
+    .join("")
+    .replaceAll(new RegExp(`(${BLANK_VAL})*\$`, "g"), "");
+  const instructions = btoa(editorEl.getValue());
+
+  navigator.clipboard
+    .writeText(
+      window.location.href.split("?")[0] +
+        `?start=${start}&instructions=${instructions}`
+    )
+    .then(() => alert("copied to clipboard"));
+});
+
+// simulate / pause button
+let playButton_simulationStatus = "paused";
+togglePlayButton.addEventListener("click", function () {
+  if (playButton_simulationStatus == "paused") {
+    state.notify({ type: MESSAGES.SIMULATE });
+  } else if (playButton_simulationStatus == "simulate") {
+    state.notify({ type: MESSAGES.PAUSE });
+  }
+});
+state.subscribe((msg) => {
+  if (msg.type == MESSAGES.PAUSE) {
+    togglePlayButton.innerHTML = "🔁 Begin";
+    playButton_simulationStatus = "paused";
+  }
+  if (msg.type == MESSAGES.SIMULATE) {
+    togglePlayButton.innerHTML = "⏸️ Pause";
+    playButton_simulationStatus = "simulate";
+  }
+});
+
+state.subscribe((msg) => {
+  if (msg.type == MESSAGES.COMPILE_STATUS) {
+    const { error, success } = msg;
+    if (error) {
+      compileStatusEl.classList.remove("success");
+      compileStatusEl.classList.add("error");
+      compileStatusEl.innerHTML = error;
+    }
+    if (success) {
+      compileStatusEl.classList.add("success");
+      compileStatusEl.classList.remove("error");
+      compileStatusEl.innerHTML = `Successful compile at ${new Date().toLocaleString()}!`;
+    }
+  }
+});
+
+state.subscribe((msg) => {
+  if (msg.type == MESSAGES.COMPILE_STATUS) {
+    const { error, success } = msg;
+    if (error) {
+      controlsEl.style.display = "none";
+    } else if (success) {
+      controlsEl.style.display = "flex";
+    }
+  }
+});
+
+state.subscribe((msg) => {
+  if (msg.type == MESSAGES.NEW_TURING_STATE) {
+    turingMachineStateEl.innerHTML = msg.value;
+  }
+});
+
+// -
+
+const main = () => {
+  let turingMachine;
+  const startString = urlParams.get("start");
+
+  state.subscribe((msg) => {
+    if (msg.type == MESSAGES.SET_CELL) {
+      const { value, cell } = msg;
+      if (turingMachine) turingMachine.setTapeAtCell(cell, value);
+    }
+    if (msg.type == MESSAGES.COMPILE) {
+      const { value } = msg;
+      try {
+        const beginState = "q0";
+        const acceptState = "f";
+        const tape = Array(TAPE_LEN)
+          .fill(BLANK_VAL)
+          .map((x, i) =>
+            startString && i < startString.length ? startString[i] : x
+          );
+
+        // put the cells into the tape
+        const cells = tape.map((_, cellId) => cell(cellId, tape[cellId]));
+        tapeEl.innerHTML = "";
+        for (const cell of cells) {
+          tapeEl.appendChild(cell);
+        }
+
+        const rules = parseRules(value, beginState, acceptState);
+        turingMachine = new TuringMachine(tape, rules, beginState, acceptState);
+
+        state.notify({ type: MESSAGES.SET_READER, cell: 0 });
+        state.notify({
+          type: MESSAGES.NEW_TURING_STATE,
+          value: turingMachine.getStateStatus(),
+        });
+        state.notify({ type: MESSAGES.COMPILE_STATUS, success: true });
+      } catch (e) {
+        state.notify({ type: MESSAGES.COMPILE_STATUS, error: e.toString() });
+      }
+    }
+    if (msg.type == MESSAGES.SIMULATE) {
+      const interval = setInterval(() => {
+        state.notify({ type: MESSAGES.NEXT_STEP });
+      }, SIMULATION_INTERVAL);
+      const subscriptionFn = (msg) => {
+        if (msg.type == MESSAGES.PAUSE) {
+          clearInterval(interval);
+          state.unsubscribe(subscriptionFn);
+        }
+      };
+      state.subscribe(subscriptionFn);
+    }
+    if (msg.type == MESSAGES.NEXT_STEP && turingMachine) {
+      const step = turingMachine.step();
+
+      const status = turingMachine.getStateStatus();
+
+      const cell = turingMachine.getHead();
+
+      if (!step) {
+        const accepting = turingMachine.isAccepting();
+        state.notify({
+          type: MESSAGES.NEW_TURING_STATE,
+          value: accepting
+            ? `<span class='success'>Accept(${status})</span>`
+            : `<span class='error'>Fail(${status})</span>`,
+        });
+      } else {
+        state.notify({
+          type: MESSAGES.NEW_TURING_STATE,
+          value: status,
+        });
+      }
+
+      state.notify({
+        type: MESSAGES.SET_READER,
+        cell,
+      });
+      state.notify({
+        type: MESSAGES.SET_CELL,
+        cell,
+        value: turingMachine.getTapeAtCell(cell),
+      });
+
+      if (!step)
+        state.notify({
+          type: MESSAGES.PAUSE,
+        });
+    }
+  });
+};
+main();

turing-machine/js/observable.js

@@ -0,0 +1,14 @@
+class Observable {
+  constructor() {
+    this.observers = [];
+  }
+  subscribe(f) {
+    this.observers.push(f);
+  }
+  unsubscribe(f) {
+    this.observers = this.observers.filter((subscriber) => subscriber !== f);
+  }
+  notify(data) {
+    this.observers.forEach((observer) => observer(data));
+  }
+}

turing-machine/js/turing_machine.js

@@ -0,0 +1,72 @@
+class TuringMachine {
+  constructor(tape = [], rules = [], initialState = "q0", acceptState = "f") {
+    this.tape = tape;
+    this.rules = this.parseRules(rules);
+    this.state = initialState;
+    this.head = 0;
+    this.acceptState = acceptState;
+
+    this.iteration = 0;
+  }
+
+  getStateStatus() {
+    return `State: ${this.state}, Step: ${this.iteration}`;
+  }
+
+  getHead() {
+    return this.head;
+  }
+
+  getState() {
+    return this.state;
+  }
+
+  getTapeAtCell(idx) {
+    return this.tape[idx];
+  }
+
+  setTapeAtCell(idx, val) {
+    this.tape[idx] = val;
+  }
+
+  isAccepting() {
+    return this.state == this.acceptState;
+  }
+
+  parseRules(rules) {
+    const parsedRules = {};
+    for (const [currentState, readSymbol, action, newState] of rules) {
+      const key = `${currentState},${readSymbol}`;
+      const value = `${newState},${action}`;
+      parsedRules[key] = value;
+    }
+    return parsedRules;
+  }
+
+  step() {
+    const currentSymbol = this.tape[this.head];
+    const key = `${this.state},${currentSymbol}`;
+    if (!(key in this.rules)) {
+      return false;
+    }
+    const rule = this.rules[key];
+    const [newState, action] = rule.split(",");
+
+    this.state = newState;
+    this.iteration++;
+
+    if (action === "R") {
+      this.head += 1;
+    } else if (action === "L") {
+      this.head -= 1;
+    } else {
+      this.tape[this.head] = action;
+    }
+
+    if (this.isAccepting()) {
+      return false;
+    }
+
+    return this.head >= 0 && this.head < this.tape.length;
+  }
+}