Add object-oriented records example

examples/object_records.myc

@@ -0,0 +1,50 @@
+;; Output: [150 130 "Insufficient funds" 130]
+
+; ---------------------------------------------------------
+; Object-Oriented Records Example
+; ---------------------------------------------------------
+; This showcase treats a record as an object by storing 
+; closures that capture private state.
+
+(do
+  ; A factory function (Constructor) for a BankAccount object
+  (def make-account (fn [initial-balance]
+    (do
+      ; 'balance' is a captured parameter, acting as private state
+      (def balance initial-balance)
+      
+      {
+        ; Method: Get current balance
+        :balance (fn [] balance)
+        
+        ; Method: Deposit money
+        :deposit (fn [amount] 
+          (assign balance (+ balance amount)))
+        
+        ; Method: Withdraw money with validation
+        :withdraw (fn [amount]
+          (if (>= balance amount)
+            (assign balance (- balance amount))
+            "Insufficient funds"))
+      }
+    )))
+
+  ; 1. Create an instance
+  (def my-acc (make-account 100))
+
+  ; 2. Call 'deposit' method
+  ; Note the double parens: (.deposit my-acc) gets the function, then we call it
+  (def b1 ((.deposit my-acc) 50)) ; balance is now 150
+
+  ; 3. Call 'withdraw' method
+  (def b2 ((.withdraw my-acc) 20)) ; balance is now 130
+
+  ; 4. Call 'withdraw' with invalid amount
+  (def error-msg ((.withdraw my-acc) 1000))
+
+  ; 5. Call 'balance' getter
+  (def final-balance ((.balance my-acc)))
+
+  ; Return summary of operations
+  [b1 b2 error-msg final-balance]
+)