diff --git a/package-lock.json b/package-lock.json
index 2b68a71..340cfaf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,8 @@
       "name": "the-abstraction-engine",
       "version": "0.0.0",
       "dependencies": {
+        "codemirror": "^6.0.1",
+        "rainbowbrackets": "github:eriknewland/rainbowbrackets",
         "react": "^18.2.0",
         "react-dom": "^18.2.0"
       },
@@ -392,6 +394,82 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/@codemirror/autocomplete": {
+      "version": "6.13.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/autocomplete/-/autocomplete-6.13.0.tgz",
+      "integrity": "sha512-SuDrho1klTINfbcMPnyro1ZxU9xJtwDMtb62R8TjL/tOl71IoOsvBo1a9x+hDvHhIzkTcJHy2VC+rmpGgYkRSw==",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0"
+      },
+      "peerDependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/commands": {
+      "version": "6.3.3",
+      "resolved": "https://registry.npmjs.org/@codemirror/commands/-/commands-6.3.3.tgz",
+      "integrity": "sha512-dO4hcF0fGT9tu1Pj1D2PvGvxjeGkbC6RGcZw6Qs74TH+Ed1gw98jmUgd2axWvIZEqTeTuFrg1lEB1KV6cK9h1A==",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.4.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.1.0"
+      }
+    },
+    "node_modules/@codemirror/language": {
+      "version": "6.10.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/language/-/language-6.10.1.tgz",
+      "integrity": "sha512-5GrXzrhq6k+gL5fjkAwt90nYDmjlzTIJV8THnxNFtNKWotMIlzzN+CpqxqwXOECnUdOndmSeWntVrVcv5axWRQ==",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.23.0",
+        "@lezer/common": "^1.1.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0",
+        "style-mod": "^4.0.0"
+      }
+    },
+    "node_modules/@codemirror/lint": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/lint/-/lint-6.5.0.tgz",
+      "integrity": "sha512-+5YyicIaaAZKU8K43IQi8TBy6mF6giGeWAH7N96Z5LC30Wm5JMjqxOYIE9mxwMG1NbhT2mA3l9hA4uuKUM3E5g==",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/search": {
+      "version": "6.5.6",
+      "resolved": "https://registry.npmjs.org/@codemirror/search/-/search-6.5.6.tgz",
+      "integrity": "sha512-rpMgcsh7o0GuCDUXKPvww+muLA1pDJaFrpq/CCHtpQJYz8xopu4D1hPcKRoDD0YlF8gZaqTNIRa4VRBWyhyy7Q==",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/state": {
+      "version": "6.4.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/state/-/state-6.4.1.tgz",
+      "integrity": "sha512-QkEyUiLhsJoZkbumGZlswmAhA7CBU02Wrz7zvH4SrcifbsqwlXShVXg65f3v/ts57W3dqyamEriMhij1Z3Zz4A=="
+    },
+    "node_modules/@codemirror/view": {
+      "version": "6.25.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/view/-/view-6.25.0.tgz",
+      "integrity": "sha512-XnMGOm6qXB8znzCko0N7k97qZayVdvqpA0JebxA5fHtgBjC/XlCPhH9TK92TahsoCKMPQlaTCUep06Dwj/+GXQ==",
+      "dependencies": {
+        "@codemirror/state": "^6.4.0",
+        "style-mod": "^4.1.0",
+        "w3c-keyname": "^2.2.4"
+      }
+    },
     "node_modules/@esbuild/aix-ppc64": {
       "version": "0.19.12",
       "resolved": "https://registry.npmjs.org/@esbuild/aix-ppc64/-/aix-ppc64-0.19.12.tgz",
@@ -956,6 +1034,27 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@lezer/common": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/@lezer/common/-/common-1.2.1.tgz",
+      "integrity": "sha512-yemX0ZD2xS/73llMZIK6KplkjIjf2EvAHcinDi/TfJ9hS25G0388+ClHt6/3but0oOxinTcQHJLDXh6w1crzFQ=="
+    },
+    "node_modules/@lezer/highlight": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/@lezer/highlight/-/highlight-1.2.0.tgz",
+      "integrity": "sha512-WrS5Mw51sGrpqjlh3d4/fOwpEV2Hd3YOkp9DBt4k8XZQcoTHZFB7sx030A6OcahF4J1nDQAa3jXlTVVYH50IFA==",
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/lr": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/@lezer/lr/-/lr-1.4.0.tgz",
+      "integrity": "sha512-Wst46p51km8gH0ZUmeNrtpRYmdlRHUpN1DQd3GFAyKANi8WVz8c2jHYTf1CVScFaCjQw1iO3ZZdqGDxQPRErTg==",
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
     "node_modules/@nodelib/fs.scandir": {
       "version": "2.1.5",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -1641,6 +1740,20 @@
         "node": ">=4"
       }
     },
+    "node_modules/codemirror": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/codemirror/-/codemirror-6.0.1.tgz",
+      "integrity": "sha512-J8j+nZ+CdWmIeFIGXEFbFPtpiYacFMDR8GlHK3IyHQJMCaVRfGx9NT+Hxivv1ckLWPvNdZqndbr/7lVhrf/Svg==",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/commands": "^6.0.0",
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/search": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0"
+      }
+    },
     "node_modules/color-convert": {
       "version": "1.9.3",
       "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-1.9.3.tgz",
@@ -1668,6 +1781,11 @@
       "integrity": "sha512-Kvp459HrV2FEJ1CAsi1Ku+MY3kasH19TFykTz2xWmMeq6bk2NU3XXvfJ+Q61m0xktWwt+1HSYf3JZsTms3aRJg==",
       "dev": true
     },
+    "node_modules/crelt": {
+      "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/crelt/-/crelt-1.0.6.tgz",
+      "integrity": "sha512-VQ2MBenTq1fWZUH9DJNGti7kKv6EeAuYr3cLwxUWhIu1baTaXh4Ib5W2CqHVqib4/MqbYGJqiL3Zb8GJZr3l4g=="
+    },
     "node_modules/cross-spawn": {
       "version": "7.0.3",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.3.tgz",
@@ -2814,6 +2932,14 @@
         }
       ]
     },
+    "node_modules/rainbowbrackets": {
+      "version": "2.0.2",
+      "resolved": "git+ssh://git@github.com/eriknewland/rainbowbrackets.git#9352b73c715aac548690936ac393e0cf6e50cb98",
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/view": "^6.9.5"
+      }
+    },
     "node_modules/react": {
       "version": "18.2.0",
       "resolved": "https://registry.npmjs.org/react/-/react-18.2.0.tgz",
@@ -3039,6 +3165,11 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/style-mod": {
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/style-mod/-/style-mod-4.1.2.tgz",
+      "integrity": "sha512-wnD1HyVqpJUI2+eKZ+eo1UwghftP6yuFheBqqe+bWCotBjC2K1YnteJILRMs3SM4V/0dLEW1SC27MWP5y+mwmw=="
+    },
     "node_modules/supports-color": {
       "version": "5.5.0",
       "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-5.5.0.tgz",
@@ -3221,6 +3352,11 @@
         }
       }
     },
+    "node_modules/w3c-keyname": {
+      "version": "2.2.8",
+      "resolved": "https://registry.npmjs.org/w3c-keyname/-/w3c-keyname-2.2.8.tgz",
+      "integrity": "sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ=="
+    },
     "node_modules/which": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
diff --git a/package.json b/package.json
index f4b2a67..9ccb2eb 100644
--- a/package.json
+++ b/package.json
@@ -10,6 +10,8 @@
     "preview": "vite preview"
   },
   "dependencies": {
+    "codemirror": "^6.0.1",
+    "rainbowbrackets": "github:eriknewland/rainbowbrackets",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"
   },
diff --git a/src/App.tsx b/src/App.tsx
index 0ae052f..3f3f67d 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -4,8 +4,8 @@ import { Miscellaneous } from "./engine/config";
 export const App = () => {
   return (
     <div className="main">
-      <div id="modal" className="modal">
-        <div className="modal-content">
+      <div id={Miscellaneous.MODAL_ID} className="modal">
+        <div id={Miscellaneous.MODAL_CONTENT_ID} className="modal-content">
           <span className="close">&times;</span>
           <p>Some text in the Modal..</p>
         </div>
diff --git a/src/css/style.css b/src/css/style.css
index ab76e98..c14682b 100644
--- a/src/css/style.css
+++ b/src/css/style.css
@@ -94,3 +94,26 @@ a:visited {
   border-radius: 0.5rem;
   margin: 0;
 }
+
+.code {
+  width: 100%;
+}
+
+button {
+  padding: 0.5rem;
+  border: none;
+  border-radius: 0.5rem;
+  background-color: var(--yellow);
+  color: var(--bg);
+  cursor: pointer;
+  transition: background 0.2s ease-in-out;
+}
+
+button:hover {
+  background-color: var(--blue);
+}
+
+.syntax-error {
+  color: var(--red);
+  background-color: var(--yellow);
+}
diff --git a/src/engine/TheAbstractionEngine.ts b/src/engine/TheAbstractionEngine.ts
index 30c3422..09419ff 100644
--- a/src/engine/TheAbstractionEngine.ts
+++ b/src/engine/TheAbstractionEngine.ts
@@ -58,7 +58,7 @@ export class TheAbstractionEngine {
     const wall = new Wall({ x: 5, y: 3 });
     this.game.addEntity(wall);
 
-    const factory = new LambdaFactory({ x: 6, y: 6 }, "(λ (x) . x)", 10);
+    const factory = new LambdaFactory({ x: 3, y: 3 }, "(λ (x) . x)", 10);
     this.game.addEntity(factory);
 
     const lockedDoor = new LockedDoor({ x: 8, y: 8 });
diff --git a/src/engine/config/constants.ts b/src/engine/config/constants.ts
index c6b592e..89f7e92 100644
--- a/src/engine/config/constants.ts
+++ b/src/engine/config/constants.ts
@@ -60,5 +60,6 @@ export namespace Miscellaneous {
   export const GRID_CELL_HEIGHT = Math.floor(HEIGHT / GRID_ROWS);
 
   export const MODAL_ID = "modal";
+  export const MODAL_CONTENT_ID = "modal-content";
   export const CANVAS_ID = "canvas";
 }
diff --git a/src/engine/entities/LambdaFactory.ts b/src/engine/entities/LambdaFactory.ts
index 0721f80..d8fc7a2 100644
--- a/src/engine/entities/LambdaFactory.ts
+++ b/src/engine/entities/LambdaFactory.ts
@@ -19,12 +19,42 @@ import {
 } from "../components";
 import { Coord2D, Direction } from "../interfaces";
 import { openModal, closeModal } from "../utils";
+import { EditorState, StateField, StateEffect, Range } from "@codemirror/state";
+import { Decoration, EditorView, keymap } from "@codemirror/view";
+import { defaultKeymap } from "@codemirror/commands";
+import rainbowBrackets from "rainbowbrackets";
+import { basicSetup } from "codemirror";
+import { parse } from "../../interpreter";
+
+interface CodeEditorState {
+  view: EditorView;
+  editorElement: HTMLElement;
+}
+
+const highlightEffect = StateEffect.define<Range<Decoration>[]>();
+const highlightExtension = StateField.define({
+  create() {
+    return Decoration.none;
+  },
+  update(value, transaction) {
+    value = value.map(transaction.changes);
+
+    for (let effect of transaction.effects) {
+      if (effect.is(highlightEffect))
+        value = value.update({ add: effect.value, sort: true });
+    }
+
+    return value;
+  },
+  provide: (f) => EditorView.decorations.from(f),
+});
 
 export class LambdaFactory extends Entity {
   private static spriteSpec: SpriteSpec = SPRITE_SPECS.get(
     Sprites.LAMBDA_FACTORY,
   ) as SpriteSpec;
 
+  private codeEditorState: CodeEditorState | null;
   private code: string;
   private spawns: number;
 
@@ -33,6 +63,7 @@ export class LambdaFactory extends Entity {
 
     this.code = code;
     this.spawns = spawns;
+    this.codeEditorState = null;
 
     this.addComponent(
       new BoundingBox(
@@ -82,36 +113,86 @@ export class LambdaFactory extends Entity {
     this.removeComponent(ComponentNames.Interactable);
   }
 
+  private spawnNewLambda(direction: Direction) {
+    const spawner = this.getComponent<LambdaSpawn>(ComponentNames.LambdaSpawn);
+    spawner.spawn(direction);
+
+    const text = this.getComponent<Text>(ComponentNames.Text);
+    text.text = spawner.spawnsLeft.toString();
+    this.addComponent(text);
+  }
+
   private onHighlight(direction: Direction) {
     if (direction === Direction.LEFT || direction === Direction.RIGHT) {
-      const interaction = () => {
-        const spawner = this.getComponent<LambdaSpawn>(
-          ComponentNames.LambdaSpawn,
-        );
-        spawner.spawn(direction);
-
-        const text = this.getComponent<Text>(ComponentNames.Text);
-        text.text = spawner.spawnsLeft.toString();
-        this.addComponent(text);
-      };
-
-      this.addComponent(new Interactable(interaction));
+      this.addComponent(new Interactable(() => this.spawnNewLambda(direction)));
       return;
     }
 
     let modalOpen = false;
+    let editorView: EditorView | null = null;
+
+    const syntaxErrorDecoration = Decoration.mark({
+      class: "syntax-error",
+    });
+
     const close = () => {
+      if (editorView) {
+        const text = editorView.state.doc.toString();
+
+        // remove all text from the editor
+        editorView.dispatch({
+          changes: {
+            from: 0,
+            to: text.length,
+            insert: "",
+          },
+        });
+        // add the new text to the editor
+        editorView.dispatch({
+          changes: {
+            from: 0,
+            to: 0,
+            insert: text,
+          },
+        });
+
+        try {
+          parse(text);
+        } catch (e: any) {
+          if (!e.location) {
+            return;
+          }
+          const {
+            location: {
+              start: { offset: start },
+              end: { offset: end },
+            },
+          } = e;
+
+          editorView.dispatch({
+            effects: highlightEffect.of([
+              syntaxErrorDecoration.range(
+                start === end ? start - 1 : start,
+                end,
+              ),
+            ]),
+          });
+
+          document.getElementById("syntax-error")!.innerText = e.message;
+
+          return;
+        }
+
+        const spawner = this.getComponent<LambdaSpawn>(
+          ComponentNames.LambdaSpawn,
+        );
+        spawner.code = text;
+        this.addComponent(spawner);
+      }
+
       modalOpen = false;
       closeModal();
 
-      const spawner = this.getComponent<LambdaSpawn>(
-        ComponentNames.LambdaSpawn,
-      );
-      spawner.code = (
-        document.getElementById("code") as HTMLTextAreaElement
-      ).value;
-      this.addComponent(spawner);
-
       document.getElementById(Miscellaneous.CANVAS_ID)!.focus();
       return;
     };
@@ -121,22 +202,36 @@ export class LambdaFactory extends Entity {
         close();
         return;
       }
-
       modalOpen = true;
-      openModal(this.codeEditor(this.code));
+
+      openModal(
+        "<div class='code'><div id='code'></div><br><p id='syntax-error' class='error'></p><button id='close-modal'>Save</button></div>",
+      );
+      const spawner = this.getComponent<LambdaSpawn>(
+        ComponentNames.LambdaSpawn,
+      );
+
+      const startState = EditorState.create({
+        doc: spawner.code,
+        extensions: [
+          basicSetup,
+          keymap.of(defaultKeymap),
+          rainbowBrackets(),
+          highlightExtension,
+        ],
+      });
+
+      const codeBox = document.getElementById("code")!;
+      editorView = new EditorView({
+        state: startState,
+        parent: codeBox,
+      });
+
+      editorView.focus();
 
       document.getElementById("close-modal")!.addEventListener("click", close);
     };
 
     this.addComponent(new Interactable(interaction));
   }
-
-  private codeEditor(code: string) {
-    return `
-      <div>
-        <textarea id="code" rows="10" cols="50">${code}</textarea>
-        <button id="close-modal">Close</button>
-      </div>
-   `;
-  }
 }
diff --git a/src/engine/utils/modal.ts b/src/engine/utils/modal.ts
index e7b36b1..48afae8 100644
--- a/src/engine/utils/modal.ts
+++ b/src/engine/utils/modal.ts
@@ -2,34 +2,37 @@ import { Miscellaneous } from "../config";
 
 let modalOpen = false;
 
-export const openModal = (content: string, id = Miscellaneous.MODAL_ID) => {
+export const openModal = (
+  content: string,
+  id = Miscellaneous.MODAL_ID,
+  contentId = Miscellaneous.MODAL_CONTENT_ID,
+) => {
   const modal = document.getElementById(id);
-  if (modal && !modalOpen) {
+  const modalContent = document.getElementById(contentId);
+  if (modal && !modalOpen && modalContent) {
     modal.style.display = "flex";
     modal.style.animation = "fadeIn 0.25s";
 
-    modal.innerHTML = `<div class="modal-content">${content}</div>`;
-    const modalContent = document.querySelector<HTMLElement>(".modal-content");
-    if (modalContent) {
-      modalContent.style.animation = "scaleUp 0.25s";
-    }
+    modalContent.innerHTML = content;
+    modalContent.style.animation = "scaleUp 0.25s";
 
     modalOpen = true;
   }
 };
 
-export const closeModal = (id = Miscellaneous.MODAL_ID) => {
+export const closeModal = (
+  id = Miscellaneous.MODAL_ID,
+  contentId = Miscellaneous.MODAL_CONTENT_ID,
+) => {
   const modal = document.getElementById(id);
-  if (modal && modalOpen) {
-    modal.style.animation = "fadeOut 0.25s";
+  const modalContent = document.getElementById(contentId);
 
-    const modalContent = document.querySelector<HTMLElement>(".modal-content");
-    if (modalContent) {
-      modalContent.style.animation = "scaleDown 0.25s";
-    }
+  if (modal && modalOpen && modalContent) {
+    modal.style.animation = "fadeOut 0.25s";
+    modalContent.style.animation = "scaleDown 0.25s";
 
     setTimeout(() => {
-      modal.innerHTML = "";
+      modalContent.innerHTML = "";
       modal.style.display = "none";
 
       modalOpen = false;
diff --git a/src/interpreter/parser.ts b/src/interpreter/parser.ts
index ea07796..5e3be0f 100644
--- a/src/interpreter/parser.ts
+++ b/src/interpreter/parser.ts
@@ -30,6 +30,6 @@ export const isVariable = (term: LambdaTerm): term is Variable => {
   return typeof term === "string";
 };
 
-export const parse = (term: string) => {
-  return peggyParser.parse(term, { library: true });
+export const parse = (term: string, library = false) => {
+  return peggyParser.parse(term, { peg$library: library });
 };
diff --git a/src/main.tsx b/src/main.tsx
index 7404467..8191a98 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -1,4 +1,5 @@
 import ReactDOM from "react-dom/client";
 import { App } from "./App.tsx";
 import "./css/style.css";
+
 ReactDOM.createRoot(document.getElementById("root")!).render(<App />);