we have persistence. persisting all store values' ASTs to localStorage

src/ast.ts

@@ -5,25 +5,25 @@ import type { Value } from './types';
 export type Literal = {
     kind: 'literal'
     value: Value
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type Variable = {
     kind: 'variable'
     name: string
-    line: number
+    line?: number
     column: number
-    start: number
+    start?: number
 }
 
 export type Constructor = {
     kind: 'constructor'
     name: string
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 // Functions
@@ -32,18 +32,18 @@ export type Lambda = {
     kind: 'lambda'
     params: string[]
     body: AST
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type Apply = {
     kind: 'apply'
     func: AST
     args: AST[]
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 // Bindings
@@ -53,9 +53,9 @@ export type Let = {
     name: string
     value: AST
     body: AST
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 // Matching
@@ -64,17 +64,17 @@ export type Match = {
     kind: 'match'
     expr: AST
     cases: MatchCase[]
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type MatchCase = {
     pattern: Pattern
     result: AST
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type Pattern =
@@ -91,43 +91,43 @@ export type Pattern =
 export type ListSpread = {
     kind: 'list-spread'
     spread: AST;
-    line: number;
-    column: number;
-    start: number;
+    line?: number;
+    column?: number;
+    start?: number;
 }
 
 export type List = {
     kind: 'list'
     elements: (AST | ListSpread)[]
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type Record = {
     kind: 'record'
     fields: { [key: string]: AST }
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type RecordAccess = {
     kind: 'record-access'
     record: AST
     field: string
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type RecordUpdate = {
     kind: 'record-update'
     record: AST
     updates: { [key: string]: AST }
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 // Top-level constructs
@@ -136,36 +136,36 @@ export type Definition = {
     kind: 'definition'
     name: string
     body: AST
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type TypeDef = {
     kind: 'typedef'
     name: string
     variants: Array<{ name: string, args: string[] }>
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type Import = {
     kind: 'import'
     module: string
     items: string[] | 'all'
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type Rebind = {
     kind: 'rebind'
     target: AST
     value: AST
-    line: number
-    column: number
-    start: number
+    line?: number
+    column?: number
+    start?: number
 }
 
 export type AST =

src/error.ts

@@ -1,14 +1,14 @@
 export class CGError extends Error {
-    line: number;
-    column: number;
-    source: string;
+    line?: number;
+    column?: number;
+    source?: string;
     errorType: 'RuntimeError' | 'ParseError';
 
     constructor(
         message: string,
-        line: number,
-        column: number,
-        source: string,
+        line?: number,
+        column?: number,
+        source?: string,
         errorType: 'RuntimeError' | 'ParseError' = 'RuntimeError'
     ) {
         super(message);
@@ -20,6 +20,10 @@ export class CGError extends Error {
     }
 
     format(): string {
+        if (this.line === undefined || this.column === undefined || !this.source) {
+            return `${this.name}: ${this.message}`;
+        }
+
         const lines = this.source.split('\n');
         const errorLine = lines[this.line - 1];
 
@@ -35,10 +39,10 @@ export class CGError extends Error {
     }
 }
 
-export function RuntimeError(message: string, line: number, column: number, source: string) {
+export function RuntimeError(message: string, line?: number, column?: number, source?: string) {
     return new CGError(message, line, column, source, 'RuntimeError');
 }
 
-export function ParseError(message: string, line: number, column: number, source: string) {
+export function ParseError(message: string, line?: number, column?: number, source?: string) {
     return new CGError(message, line, column, source, 'ParseError');
 }

src/interpreter.ts

@@ -13,7 +13,7 @@ export function evaluate(ast: AST, env: Env, source: string): Value {
             const val = env.get(ast.name);
 
             if (val === undefined)
-                throw RuntimeError( `Unknown variable: ${ast.name}`, ast.line, ast.column, source);
+                throw RuntimeError(`Unknown variable: ${ast.name}`, ast.line, ast.column, source);
 
             recordDependency(ast.name);
 

src/main.ts

@@ -6,8 +6,7 @@ import { runApp } from './runtime';
 import { builtins } from './builtins';
 import { CGError } from './error';
 import { createStore, startTracking, stopTracking, buildDependents } from './store';
-// import type { Store } from './store'
-
+import { loadStore } from './persistence';
 
 import stdlibCode from './stdlib.cg?raw';
 import designTokensCode from './design-tokens.cg?raw';
@@ -33,18 +32,32 @@ try {
     const env: Env = new Map(Object.entries(builtins));
     const store = createStore();
 
+    const persisted = loadStore();
+
     for (const def of definitions) {
+        const body = persisted?.[def.name]?.body ?? def.body;
+
         const deps = startTracking(def.name);
-        const value = evaluate(def.body, env, cgCode);
+        const value = evaluate(body, env, cgCode);
         stopTracking();
 
         env.set(def.name, value);
+        store.set(def.name, { value, body, dependencies: deps });
+    }
 
-        store.set(def.name, {
-            value,
-            body: def.body,
-            dependencies: deps
-        });
+    // Load persisted store entries
+    if (persisted) {
+        for (const [name, data] of Object.entries(persisted)) {
+            if (!store.has(name) && data.source === 'runtime') {
+                const deps = startTracking(name);
+                const value = evaluate(data.body, env, "");
+                stopTracking();
+
+                env.set(name, value);
+
+                store.set(name, { value, body: data.body, dependencies: deps });
+            }
+        }
     }
 
     const dependents = buildDependents(store);

src/persistence.ts

@@ -0,0 +1,29 @@
+import type { AST } from './ast'
+import type { Store } from './store'
+
+const STORAGE_KEY = 'cg_store';
+
+export function saveStore(store: Store) {
+    const data: Record<string, any> = {};
+    for (const [name, entry] of store) {
+        data[name] = {
+            body: entry.body,
+            source: 'file'
+        };
+    }
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(data));
+}
+
+export function loadStore(): Record<string, { body: AST, source: string }> | null {
+    try {
+        const raw = localStorage.getItem(STORAGE_KEY);
+        if (!raw) return null;
+        return JSON.parse(raw);
+    } catch(e) {
+        return null;
+    }
+}
+
+export function clearStore() {
+    localStorage.remove(STORAGE_KEY);
+}

src/runtime.ts

@@ -6,6 +6,8 @@ import { CGError } from './error';
 import type { AST } from './ast';
 import type { Env } from './env';
 import type { Store } from './store';
+import { saveStore } from './persistence';
+import { valueToAST } from './valueToAST';
 
 export type App = {
     init: Value;
@@ -284,9 +286,12 @@ export function runApp(app: App, canvas: HTMLCanvasElement, source: string, env:
             const entry = store.get(name);
             if (entry) {
                 entry.value = newValue;
+                entry.body = valueToAST(newValue);
             }
 
             recomputeDependents(name);
+
+            saveStore(store);
             return;
         }
 

src/textinput-test.cg

@@ -6,6 +6,8 @@ testApp = {
     combinedText = email & " " & password
 };
 
+topLevelText = "";
+
 update = state event \ event
   | _ \ state;
 
@@ -18,7 +20,7 @@ view = state viewport \
      children = [
        textInput {
          key = "email",
-         initialValue = "",
+         initialValue = testApp.email,
          initialFocus = True,
          w = 300,
          h = 40,
@@ -26,7 +28,7 @@ view = state viewport \
        },
        textInput {
          key = "password",
-         initialValue = "",
+         initialValue = testApp.password,
          initialFocus = False,
          w = 300,
          h = 40,
@@ -34,7 +36,16 @@ view = state viewport \
        },
        Text { content = "Username: " & testApp.email, x = 8, y = 16 },
        Text { content = "Password: " & testApp.password, x = 8, y = 16 },
-       Text { content = "Combined: " & testApp.combinedText, x = 8, y = 16 }
+       Text { content = "Combined: " & testApp.combinedText, x = 8, y = 16 },
+       textInput {
+         key = "top-level-text",
+         initialValue = topLevelText,
+         initialFocus = False,
+         w = 300,
+         h = 40,
+         onChange = text \ topLevelText := text
+       },
+       Text { content = "Top Level: " & topLevelText, x = 8, y = 16 }
      ]
    }
  };

src/valueToAST.ts

@@ -0,0 +1,45 @@
+import type { AST } from './ast'
+import type { Value } from './types'
+
+export function valueToAST(value: Value): AST {
+    switch (value.kind) {
+        case 'int':
+        case 'float':
+        case 'string':
+            return { kind: 'literal', value };
+
+        case 'list':
+            return {
+                kind: 'list',
+                elements: value.elements.map(valueToAST)
+            };
+
+        case 'record':
+            const fields: { [key: string]: AST } = {};
+            for (const [k, v] of Object.entries(value.fields)) {
+                if (value.fieldMeta && value.fieldMeta?.[k]?.dependencies?.size > 0) {
+                    fields[k] = value.fieldMeta[k].body;
+                } else {
+                    fields[k] = valueToAST(v);
+                }
+            }
+
+            return { kind: 'record', fields };
+
+        case 'constructor':
+            return {
+                kind: 'constructor',
+                name: value.name
+            };
+
+        case 'closure':
+            return {
+                kind: 'lambda',
+                params: value.params,
+                body: value.body
+            };
+
+        default:
+            throw new Error(`Cannot convert ${(value as any).kind} to AST`);
+    }
+}