refactor: Update GetCurrentStack to return []Value instead of []float64

- Changed GetCurrentStack() to return []Value to preserve value types
- Updated test to use Value.Number() method for comparison
- Boolean values are now correctly preserved in stack inspection

This ensures that boolean values returned from comparison operators
(gt, lt, etc.) are preserved when inspecting the stack.

2 files changed, 6 insertions, 9 deletions

diff --git a/internal/rpn/rpn_state.go b/internal/rpn/rpn_state.go
index 30cf1cf..eb54add 100644
--- a/internal/rpn/rpn_state.go
+++ b/internal/rpn/rpn_state.go
@@ -39,16 +39,12 @@ func (r *RPN) SetMode(mode CalculationMode) {
 }
 
 // GetCurrentStack returns a copy of the current stack for inspection.
-func (r *RPN) GetCurrentStack() []float64 {
+// Returns []Value to preserve value types (numbers and booleans).
+func (r *RPN) GetCurrentStack() []Value {
 	if r.currentStack == nil {
 		return nil
 	}
-	values := r.currentStack.Values()
-	result := make([]float64, len(values))
-	for i, v := range values {
-		result[i] = v.Number()
-	}
-	return result
+	return r.currentStack.Values()
 }
 
 // SetCurrentStack sets the current stack from a slice of values.
diff --git a/internal/rpn/rpn_test.go b/internal/rpn/rpn_test.go
index e3bf43e..c529ffa 100644
--- a/internal/rpn/rpn_test.go
+++ b/internal/rpn/rpn_test.go
@@ -755,7 +755,8 @@ func TestRPNGetCurrentStack(t *testing.T) {
 	if len(stack) != 3 {
 		t.Errorf("Stack length = %d, want 3", len(stack))
 	}
-	if stack[0] != 1 || stack[1] != 2 || stack[2] != 3 {
+	// Use Number() method to compare values
+	if stack[0].Number() != 1 || stack[1].Number() != 2 || stack[2].Number() != 3 {
 		t.Errorf("Stack = %v, want [1 2 3]", stack)
 	}
 }
@@ -1210,7 +1211,7 @@ func TestRPNStackPreservation(t *testing.T) {
 
 	// Stack should preserve 3
 	stack := rpnCalc.GetCurrentStack()
-	if len(stack) != 1 || stack[0] != 3.0 {
+	if len(stack) != 1 || stack[0].Number() != 3.0 {
 		t.Errorf("Stack should be [3], got %v", stack)
 	}