lambdas and application now in AST, types and interpreter

src/main.ts

@@ -28,3 +28,47 @@ const env: Env = new Map();
 const res = evaluate(ast, env);
 
 console.log(res);
+
+const ast2: AST = {
+    kind: 'let',
+    name: 'add',
+    value: {
+        kind: 'lambda',
+        params: ['x', 'y'],
+        body: {
+            kind: 'binaryop',
+            operator: '+',
+            left: {
+                kind: 'variable',
+                name: 'x',
+            },
+            right: {
+                kind: 'variable',
+                name: 'y',
+            }
+        }
+    },
+    body: {
+        kind: 'apply',
+        func: {
+            kind: 'variable',
+            name: 'add'
+        },
+        args: [
+            {
+                kind: 'literal',
+                value: { kind: 'int', value: 2 }
+            },
+            {
+                kind: 'literal',
+                value: { kind: 'int', value: 3 }
+            },
+        ]
+    }
+};
+
+const env2: Env = new Map();
+
+const res2 = evaluate(ast2, env2);
+
+console.log(res2);