Similarly: over time almost every boolean becomes an enum. I'm a bit surprised the article doesn't mention enum parameters as a possible alternative to booleans

Similarly: over time almost every boolean becomes an enum. I'm a bit surprised the article doesn't mention enum parameters as a possible alternative to booleans. In this example the call-site could instead look like `getUserMessages(userId, MessageStyle.SUMMARY)`. Naming the enum is always harder than naming the boolean but that's kinda the point.