Common Programming Concepts

Every language gives you a way to name a value, a set of types those values come in, operators to combine them, and statements to decide what runs next. This chapter is those four things in the form Zuri gives them.

If this is your first language, read the sections in order; each one uses only what came before it. If you already program, read Operators and Control Flow attentively — those are where the same syntax you already know does something different here.

The Reserved Words

Before anything else, the words you cannot use as names. Zuri reserves 31 keywords:

and       as        assert    break     catch     class     const
continue  def       default   do        echo      else      false
for       if        import    in        iter      nil       or
parent    raise     return    self      static    true      using
var       when      while

Every one is lowercase, and every one is explained somewhere in this book. Appendix A is the index, with a one-line summary and a pointer for each.

Three things are not in that list, and are worth noticing now:

• print is not a keyword. It is an ordinary built-in function, and you could shadow it with a variable of your own if you wanted to. echo is a keyword.
• There is no function, int, string or bool keyword. Type names are ordinary identifiers, which is why they can appear as annotations without being reserved.
• There is no try, finally, switch, case, new, this, public or private. The equivalents are catch, using, when, calling the class directly, self, and a leading underscore.