parsing record access and update

src/ast.ts

@@ -158,6 +158,13 @@ export function prettyPrint(ast: AST, indent = 0): string {
             const params = ast.params.join(', ')
             return `${i}(${params}) => ${prettyPrint(ast.body)}`
 
+        case 'record-access':
+            return `${i}${prettyPrint(ast.record)}.${ast.field}`
+
+        case 'record-update':
+            const updates = Object.entries(ast.updates).map(([k, v]) => `${k} = ${prettyPrint(v, 0)}`).join(', ');
+            return `${i}${prettyPrint(ast.record)} { ${updates} }`
+
         default:
             return `${i}${ast.kind}`
     }

src/main.ts

@@ -25,7 +25,7 @@ console.log(tokenize(str));
 // const tokens2 = tokenize("let x = (y) => 5 + y in x(3)");
 // const tokens2 = tokenize("let x = 5 in x * 4");
 // const tokens2 = tokenize("(x, y) => x + y");
-const tokens2 = tokenize(`a b \\ a + b`);
+const tokens2 = tokenize('point { x = 3 }');
 const p2 = new Parser(tokens2);
 const ast3 = p2.parse();
 console.log(ast3);

src/parser.ts

@@ -148,16 +148,54 @@ export class Parser {
     }
 
     private parseApplication(): AST {
-        let func = this.parsePrimary();
+        let func = this.parsePostfix();
 
         while (this.canStartPrimary()) {
-            const arg = this.parsePrimary();
+            const arg = this.parsePostfix();
             func = { kind: 'apply', func, args: [arg] };
         }
 
         return func;
     }
 
+    private parsePostfix(): AST {
+        let expr = this.parsePrimary();
+
+        while (true) {
+            if (this.current().kind === 'dot') {
+                // Record access
+                this.advance();
+                const fieldToken = this.expect('ident');
+                const field = (fieldToken as { value: string }).value;
+                expr = { kind: 'record-access', record: expr, field };
+            } else if (this.current().kind === 'open-brace') {
+                // Record update
+                this.advance();
+                const updates: { [key: string]: AST } = {};
+                let first = true;
+
+                while (this.current().kind !== 'close-brace') {
+                    if (!first) {
+                        this.expect('comma');
+                    }
+                    first = false;
+
+                    const keyToken = this.expect('ident');
+                    const key = (keyToken as { value: string }).value;
+                    this.expect('equals');
+                    updates[key] = this.parseExpression();
+                }
+
+                this.expect('close-brace');
+                expr = { kind: 'record-update', record: expr, updates }
+            } else {
+                break;
+            }
+        }
+
+        return expr;
+    }
+
     private parsePrimary(): AST {
         const token = this.current();