Naive state management + syntax check works!

src/app-state.ts

@@ -1,9 +1,18 @@
 // Portions of this file are Copyright 2021 Google LLC, and licensed under GPL2+. See COPYING.
 
+import * as monaco from 'monaco-editor/esm/vs/editor/editor.api';
+
+import { createContext } from "react"
+import { Model } from "./model"
+
 export interface State {
-  source: {
-    content: string
+  params: {
+    source: string,
   },
+  checkerRun?: {
+    logText: string,
+    markers: monaco.editor.IMarkerData[]
+  }
   output?: {
     path: string,
     timestamp: number,
@@ -12,3 +21,12 @@ export interface State {
   },
 };
 
+export const ModelContext = createContext(new Model(
+  {
+    params: {
+      source: ''
+    }
+  },
+  () => { throw new Error('Not implemented'); }
+));
+