Language now supports top level definitions. no more last-expression-is-a-value thing, it's also a def. Host knows to run the special `os` def

src/ast.ts

@@ -2,6 +2,7 @@ import type { Value } from './types';
 
 // Literals and Variables
 
+
 export type Literal = {
     kind: 'literal'
     value: Value

src/main.ts

@@ -25,14 +25,20 @@ const cgCode = stdlibCode + '\n' +
 try {
     const tokens = tokenize(cgCode);
     const parser = new Parser(tokens, cgCode);
-    const ast = parser.parse();
+    const definitions = parser.parse();
     // console.log(ast);
 
     const env: Env = new Map(Object.entries(builtins));
-    const appRecord = evaluate(ast, env, cgCode);
-    // console.log("appRecord", appRecord);
 
-    if (appRecord.kind !== 'record')
+    for (const def of definitions) {
+        const value = evaluate(def.body, env, cgCode);
+        env.set(def.name, value);
+    }
+
+    const appRecord = env.get('os');
+    console.log("appRecord", appRecord);
+
+    if (!appRecord || appRecord.kind !== 'record')
         throw new Error('Expected record');
 
     const init = appRecord.fields.init;

src/parser.ts

@@ -1,5 +1,5 @@
 import type { Token } from './lexer'
-import type { AST, MatchCase, Pattern } from './ast'
+import type { AST, MatchCase, Pattern, Definition } from './ast'
 import { ParseError } from './error'
 
 export class Parser {
@@ -114,8 +114,29 @@ export class Parser {
         }
     }
 
-    parse(): AST {
-        return this.parseExpression();
+    parse(): Definition[] {
+        const definitions: Definition[] = [];
+
+        while (this.current().kind !== 'eof') {
+            definitions.push(this.parseDefinition());
+        }
+
+        return definitions;
+    }
+
+    private parseDefinition(): Definition {
+        const nameToken = this.expect('ident');
+        const name = (nameToken as { value: string }).value;
+
+        this.expect('equals');
+
+        const body = this.parseExpression();
+
+        if (this.current().kind !== 'eof') {
+            this.expect('semicolon');
+        }
+
+        return { kind: 'definition', name, body, ...this.getPos(nameToken) };
     }
 
     private parseExpression(): AST {

src/textinput-test.cg

@@ -37,4 +37,4 @@ view = state viewport \
    }
  };
 
-{ init = init, update = update, view = view }
+os = { init = init, update = update, view = view }