internal/rpn: Reorder functions to place public before private

According to Go best practices for this project, public functions and
methods should appear before private ones in the file. The private
methods (evaluate, handleAssignment) were placed between public methods.

This reordering improves code organization and maintainability while
maintaining identical functionality.

1 files changed, 59 insertions, 59 deletions

diff --git a/internal/rpn/rpn.go b/internal/rpn/rpn.go
index debc2c8..5bf7e7e 100644
--- a/internal/rpn/rpn.go
+++ b/internal/rpn/rpn.go
@@ -52,65 +52,6 @@ func (r *RPN) ParseAndEvaluate(input string) (string, error) {
 	return r.evaluate(tokens)
 }
 
-// handleAssignment checks if the input is an assignment format and handles it.
-// Returns (result string, isAssignment bool, error error).
-func (r *RPN) handleAssignment(input string) (string, bool, error) {
-	if !strings.Contains(input, " = ") {
-		return "", false, nil
-	}
-
-	// Handle single assignment: "name = value"
-	if parts := strings.SplitN(input, " = ", 2); len(parts) == 2 {
-		name := strings.TrimSpace(parts[0])
-		valueStr := strings.TrimSpace(parts[1])
-
-		// Validate name is a single word (variable name)
-		nameFields := strings.Fields(name)
-		if len(nameFields) == 1 {
-			// Validate value is a single number
-			valueFields := strings.Fields(valueStr)
-			if len(valueFields) == 1 {
-				val, err := strconv.ParseFloat(valueFields[0], 64)
-				if err != nil {
-					return "", false, fmt.Errorf("invalid value '%s' for assignment: %w", valueFields[0], err)
-				}
-				if err := r.vars.SetVariable(nameFields[0], val); err != nil {
-					return "", false, err
-				}
-				return fmt.Sprintf("%s = %.10g", nameFields[0], val), true, nil
-			}
-		}
-	}
-
-	// Handle assignment with expression: "name value = expression..."
-	pos := strings.Index(input, " = ")
-	if pos >= 0 {
-		before := input[:pos]  // "name value"
-		after := input[pos+3:] // "expr..."
-
-		beforeFields := strings.Fields(before)
-		if len(beforeFields) == 2 {
-			name := beforeFields[0]
-			valueStr := beforeFields[1]
-
-			// Try to parse value as a number
-			val, err := strconv.ParseFloat(valueStr, 64)
-			if err == nil {
-				// Valid assignment pattern: "name value = expr..."
-				if err := r.vars.SetVariable(name, val); err != nil {
-					return "", false, err
-				}
-
-				// Evaluate the remaining expression
-				result, err := r.evaluate(strings.Fields(strings.TrimSpace(after)))
-				return result, true, err
-			}
-		}
-	}
-
-	return "", false, nil
-}
-
 // ResultStack returns the final stack state after evaluation.
 // This is useful for commands that need to show the stack without consuming it.
 func (r *RPN) ResultStack(tokens []string) (string, error) {
@@ -399,3 +340,62 @@ func (r *RPN) evaluate(tokens []string) (string, error) {
 	val, _ := stack.Pop()
 	return fmt.Sprintf("%.10g", val), nil
 }
+
+// handleAssignment checks if the input is an assignment format and handles it.
+// Returns (result string, isAssignment bool, error error).
+func (r *RPN) handleAssignment(input string) (string, bool, error) {
+	if !strings.Contains(input, " = ") {
+		return "", false, nil
+	}
+
+	// Handle single assignment: "name = value"
+	if parts := strings.SplitN(input, " = ", 2); len(parts) == 2 {
+		name := strings.TrimSpace(parts[0])
+		valueStr := strings.TrimSpace(parts[1])
+
+		// Validate name is a single word (variable name)
+		nameFields := strings.Fields(name)
+		if len(nameFields) == 1 {
+			// Validate value is a single number
+			valueFields := strings.Fields(valueStr)
+			if len(valueFields) == 1 {
+				val, err := strconv.ParseFloat(valueFields[0], 64)
+				if err != nil {
+					return "", false, fmt.Errorf("invalid value '%s' for assignment: %w", valueFields[0], err)
+				}
+				if err := r.vars.SetVariable(nameFields[0], val); err != nil {
+					return "", false, err
+				}
+				return fmt.Sprintf("%s = %.10g", nameFields[0], val), true, nil
+			}
+		}
+	}
+
+	// Handle assignment with expression: "name value = expression..."
+	pos := strings.Index(input, " = ")
+	if pos >= 0 {
+		before := input[:pos]  // "name value"
+		after := input[pos+3:] // "expr..."
+
+		beforeFields := strings.Fields(before)
+		if len(beforeFields) == 2 {
+			name := beforeFields[0]
+			valueStr := beforeFields[1]
+
+			// Try to parse value as a number
+			val, err := strconv.ParseFloat(valueStr, 64)
+			if err == nil {
+				// Valid assignment pattern: "name value = expr..."
+				if err := r.vars.SetVariable(name, val); err != nil {
+					return "", false, err
+				}
+
+				// Evaluate the remaining expression
+				result, err := r.evaluate(strings.Fields(strings.TrimSpace(after)))
+				return result, true, err
+			}
+		}
+	}
+
+	return "", false, nil
+}