From b5bd084ee470d841a550781d45edddb6f01b29f5 Mon Sep 17 00:00:00 2001
From: Dustin Swan <dustin@dustinswan.com>
Date: Sun, 1 Feb 2026 16:20:13 -0700
Subject: [PATCH] interpreting lists, records, constructors

---
 src/ast.ts         | 10 +++++-----
 src/interpreter.ts | 22 ++++++++++++++++++++++
 src/main.ts        |  4 +++-
 3 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/ast.ts b/src/ast.ts
index 416c069..e608f63 100644
--- a/src/ast.ts
+++ b/src/ast.ts
@@ -63,6 +63,11 @@ export type Pattern =
 
 // Data Structures
 
+export type List = {
+    kind: 'list'
+    elements: AST[]
+}
+
 export type Record = {
     kind: 'record'
     fields: { [key: string]: AST }
@@ -80,11 +85,6 @@ export type RecordUpdate = {
     updates: { [key: string]: AST }
 }
 
-export type List = {
-    kind: 'list'
-    elements: AST[]
-}
-
 // Top-level constructs
 
 export type Definition = {
diff --git a/src/interpreter.ts b/src/interpreter.ts
index 849ea47..9c4d071 100644
--- a/src/interpreter.ts
+++ b/src/interpreter.ts
@@ -13,6 +13,28 @@ export function evaluate(ast: AST, env: Env): Value {
                 throw new Error(`Unknown variable: ${ast.name}`);
             return val;
 
+        case 'list':
+            return {
+                kind: 'list',
+                elements: ast.elements.map(el => evaluate(el, env))
+            };
+
+        case 'record':
+            const fields: { [key: string]: Value } = {};
+
+            Object.entries(ast.fields).forEach(([k, v]) => {
+                fields[k] = evaluate(v, env);
+            });
+
+            return { kind: 'record', fields };
+
+        case 'constructor':
+            return {
+                kind: 'constructor',
+                name: ast.name,
+                args: [] // TODO: constructors args
+            };
+
         case 'let':
             const val2 = evaluate(ast.value, env);
             const newEnv = new Map(env).set(ast.name, val2);
diff --git a/src/main.ts b/src/main.ts
index 5abc261..17e6278 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -27,7 +27,9 @@ console.log(tokenize(str));
 // const tokens2 = tokenize("(x, y) => x + y");
 // const tokens2 = tokenize('point { x = 3 }');
 // const tokens2 = tokenize('add1 = (x \\ x + 1); add1 3');
-const tokens2 = tokenize('sum = x y \\ x + y; sum 5 3');
+// const tokens2 = tokenize('sum = x y \\ x + y; sum 5 3');
+// const tokens2 = tokenize('[1, 2, 3]');
+const tokens2 = tokenize('c = 5; { a = 3, b = c }');
 const p2 = new Parser(tokens2);
 const ast3 = p2.parse();
 console.log(ast3);