records in the store

src/builtins.ts

@@ -1,4 +1,4 @@
-import type { Value, NativeFunction } from './types'
+import type { Value } from './types'
 
 const measureCanvas = document.createElement('canvas');
 const measureCtx = measureCanvas.getContext('2d')!;
@@ -468,7 +468,7 @@ export const builtins: { [name: string]: Value } = {
         name: 'debug',
         arity: 2,
         fn: (label, value) => {
-            const l = expectString(label, 'debug');
+            expectString(label, 'debug');
             return value;
         }
     }

src/interpreter.ts

@@ -202,17 +202,49 @@ export function evaluate(ast: AST, env: Env, source: string): Value {
         }
 
         case 'rebind': {
-            if (ast.target.kind !== 'variable')
-                throw new Error('Rebind target must be a variable');
-
-            const name = ast.target.name;
             const value = evaluate(ast.value, env, source);
 
-            return {
-                kind: 'constructor',
-                name: 'Rebind',
-                args: [{ kind: 'string', value: name }, value]
-            };
+            if (ast.target.kind === 'variable') {
+                const name = ast.target.name;
+                return {
+                    kind: 'constructor',
+                    name: 'Rebind',
+                    args: [{ kind: 'string', value: name }, value]
+                };
+            }
+
+            if (ast.target.kind === 'record-access') {
+                let current: AST = ast.target;
+                const path: string[] = [];
+
+                while (current.kind === 'record-access') {
+                    path.unshift(current.field);
+                    current = current.record;
+                }
+
+                if (current.kind !== 'variable')
+                    throw RuntimeError('Rebind target must be a variable or field access', ast.line, ast.column, source);
+
+                const rootName = current.name;
+                const rootValue = env.get(rootName);
+
+                if (!rootValue)
+                    throw RuntimeError(`Unknown variable: ${rootName}`, ast.line, ast.column, source);
+
+                // const newRoot = updatePath(rootValue, path, value, ast.line, ast.column, source);
+
+                return {
+                    kind: 'constructor',
+                    name: 'Rebind',
+                    args: [
+                        { kind: 'string', value: rootName },
+                        { kind: 'list', elements: path.map(p => ({ kind: 'string', value: p })) },
+                        value
+                    ]
+                };
+            }
+
+            throw RuntimeError('Rebind target must be a variable or field access', ast.line, ast.column, source);
         }
 
         default:
@@ -297,5 +329,4 @@ function matchPattern(value: Value, pattern: Pattern): Bindings | null {
             return bindings;
         }
     }
-
 }

src/runtime.ts

@@ -187,7 +187,7 @@ export function runApp(app: App, canvas: HTMLCanvasElement, source: string, env:
         };
 
         try {
-            const callEnv = new Map(app.view.env);
+            const callEnv = new Map(env);
             callEnv.set(app.view.params[0], state);
             callEnv.set(app.view.params[1], viewport);
             const uiValue = evaluate(app.view.body, callEnv, source);
@@ -223,13 +223,25 @@ export function runApp(app: App, canvas: HTMLCanvasElement, source: string, env:
         }
 
         if (event.kind === 'constructor' && event.name === 'Rebind') {
-            if (event.args.length === 2 && event.args[0].kind === 'string') {
-                const name = event.args[0].value;
-                const value = event.args[1];
-                env.set(name, value);
-                rerender();
-                return;
+            if (event.args[0].kind !== 'string') return;
+            const name = event.args[0].value;
+
+            if (event.args.length === 2) {
+                // Rebind "name" value
+                env.set(name, event.args[1]);
+            } else if (event.args.length === 3 && event.args[1].kind === 'list') {
+                // Rebind "name" ["path"]
+                const pathList = (event.args[1] as { elements: Value[] });
+                const path = pathList.elements.map((e: Value) => e.kind === 'string' ? e.value : '');
+                const currentValue = env.get(name);
+                if (currentValue) {
+                    const newValue = updatePath(currentValue, path, event.args[2]);
+                    env.set(name, newValue);
+                }
             }
+
+            rerender();
+            return;
         }
 
         if (app.update.kind !== 'closure')
@@ -321,3 +333,19 @@ export function runApp(app: App, canvas: HTMLCanvasElement, source: string, env:
 
     rerender();
 }
+
+function updatePath(obj: Value, path: string[], value: Value): Value {
+    if (path.length === 0) return value;
+
+    if (obj.kind !== 'record')
+        throw new Error('Cannot access field on non-record');
+
+    const [field, ...rest] = path;
+    return {
+        kind: 'record',
+        fields: {
+            ...obj.fields,
+            [field]: updatePath(obj.fields[field], rest, value)
+        }
+    };
+}

src/textinput-test.cg

@@ -1,7 +1,9 @@
 init = {};
 
-email = "";
-password = "";
+testApp = {
+    email = "",
+    password = ""
+};
 
 update = state event \ event
   | _ \ state;
@@ -19,7 +21,7 @@ view = state viewport \
          initialFocus = True,
          w = 300,
          h = 40,
-         onChange = text \ email := text
+         onChange = text \ testApp.email := text
        },
        textInput {
          key = "password",
@@ -27,10 +29,10 @@ view = state viewport \
          initialFocus = False,
          w = 300,
          h = 40,
-         onChange = text \ password := text
+         onChange = text \ testApp.password := text
        },
-       Text { content = "Username: " & email, x = 8, y = 16 },
-       Text { content = "Password: " & password, x = 8, y = 16 }
+       Text { content = "Username: " & testApp.email, x = 8, y = 16 },
+       Text { content = "Password: " & testApp.password, x = 8, y = 16 }
      ]
    }
  };