> java.util.Calendar that has setFirstDayOfWeek(int), the default depends on the locale used to create the Calendar That is exactly the kind of hidden assumpti

> java.util.Calendar that has setFirstDayOfWeek(int), the default depends on the locale used to create the Calendar That is exactly the kind of hidden assumption that I’m trying to fight against! If the date and the locale were both passed in as parameters, preferably just plain data, this would be a transparent function. Instead, you have to find and read through the documentation to see what kind of mischief is going on. And you have to do that every time you encounter a Java.until.Calendar. Edit to clarify: if “locale” is some class, you have to learn that class DSL to examine it, and depend on a runtime debugger that does the same. If “locale” is just a hash map, you can examine the values without a lot of faff.