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+# Enhanced Case Statements - Implementation Summary
+
+## 🎉 Implementation Complete - All Tests Passing!
+
+### **Primary Goal Achieved: FizzBuzz Implementation**
+```plaintext
+fizzbuzz_test : n ->
+  when (n % 3) (n % 5) is
+    0 0 then "FizzBuzz"
+    0 _ then "Fizz"
+    _ 0 then "Buzz"
+    _ _ then n;
+
+// Test Results:
+fizzbuzz_test 15;  // "FizzBuzz"
+fizzbuzz_test 3;   // "Fizz"
+fizzbuzz_test 5;   // "Buzz"
+fizzbuzz_test 7;   // 7
+```
+
+### **New Capabilities Added**
+
+#### 1. **Multi-value Patterns with Expressions**
+```plaintext
+// Complex expressions in parentheses
+when (x % 2) (y % 2) is
+  0 0 then "both even"
+  0 1 then "x even, y odd"
+  1 0 then "x odd, y even"
+  1 1 then "both odd";
+```
+
+#### 2. **Table Access in When Expressions**
+```plaintext
+user : {role: "admin", level: 5};
+
+when u.role is
+  "admin" then "admin user"
+  "user" then "regular user"
+  _ then "unknown role";
+```
+
+#### 3. **Function Calls in When Expressions** (with parentheses)
+```plaintext
+is_even : n -> n % 2 = 0;
+
+when (is_even n) is
+  true then "even number"
+  false then "odd number";
+```
+
+#### 4. **Parenthesized Expressions in Patterns**
+```plaintext
+when (complex_func x y) is
+  result then "matched"
+  _ then "no match";
+```
+
+### **Language Design Decisions**
+
+#### **Function Calls Require Parentheses**
+This is a deliberate design choice for clarity and consistency:
+
+**✅ Correct:**
+```plaintext
+when (is_even n) is true then "even"
+when (complex_func x y) is result then "matched"
+```
+
+**❌ Incorrect:**
+```plaintext
+when is_even n is true then "even"  // Ambiguous parsing
+```
+
+**Benefits:**
+- **Zero breaking changes** - No existing code affected
+- **Clear intent** - Parentheses make function calls explicit
+- **Language consistency** - Matches other disambiguation patterns
+- **Parser simplicity** - Cleaner, more maintainable code
+
+### **Backward Compatibility**
+
+**✅ Perfect Backward Compatibility:**
+- All existing when expressions continue to work unchanged
+- Simple value matching: `when n is 0 then 1`
+- Comparison patterns: `when score is score >= 90 then "A"`
+- Multi-value patterns: `when x y is 0 0 then "both zero"`
+- Wildcard patterns: `when n is _ then "other"`
+
+### **Test Results**
+
+**✅ All Tests Passing:**
+- `tests/22_parser_limitations.txt` - All enhanced features working
+- `tests/07_case_expressions.txt` - Backward compatibility confirmed
+- `tests/08_first_class_functions.txt` - No regressions
+- `tests/10_standard_library.txt` - Standard library intact
+- Custom FizzBuzz tests - Primary goal validated
+
+### **Implementation Details**
+
+#### **Parser Changes Made:**
+1. **Enhanced `parseWhenExpression()`** - Uses `parsePrimary()` for complex values
+2. **Added parenthesized expression support** - Patterns can now handle `(expr)`
+3. **Improved function call detection** - Better argument parsing in patterns
+4. **Maintained backward compatibility** - All existing patterns work unchanged
+
+#### **Key Technical Achievements:**
+- **Multi-value patterns with expressions** - Enables tuple-like pattern matching
+- **Table access in when expressions** - Full table property access support
+- **Function calls in when expressions** - With parentheses for clarity
+- **Zero breaking changes** - Perfect backward compatibility
+
+### **Use Cases Enabled**
+
+#### 1. **FizzBuzz and Similar Problems**
+```plaintext
+// Multiple condition checking
+when (n % 3) (n % 5) is
+  0 0 then "FizzBuzz"
+  0 _ then "Fizz"
+  _ 0 then "Buzz"
+  _ _ then n;
+```
+
+#### 2. **Complex Data Validation**
+```plaintext
+// Multi-field validation
+when (validate_name name) (validate_age age) is
+  true true then "valid user"
+  true false then "invalid age"
+  false true then "invalid name"
+  false false then "invalid user";
+```
+
+#### 3. **Table-based Pattern Matching**
+```plaintext
+// User role checking
+when user.role is
+  "admin" then "admin access"
+  "user" then "user access"
+  _ then "no access";
+```
+
+### **Future Enhancements**
+
+The foundation is now in place for:
+- **Helper combinators** for common pattern matching scenarios
+- **Pattern matching utilities** for complex pattern construction
+- **Performance optimizations** for common patterns
+- **Additional pattern types** (destructuring, guard clauses, etc.)
+
+### **Conclusion**
+
+**🎉 Mission Accomplished!**
+
+The enhanced case statements implementation successfully:
+- ✅ **Solves the FizzBuzz problem** - Primary goal achieved
+- ✅ **Enables complex pattern matching** - Multi-value patterns with expressions
+- ✅ **Maintains backward compatibility** - Zero breaking changes
+- ✅ **Provides clear language design** - Parentheses for function calls
+- ✅ **Passes all tests** - Implementation validated and production-ready
+
+The language now supports sophisticated pattern matching scenarios while maintaining its functional programming philosophy and existing code compatibility. 
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