In my mind, one important feature of a first programming language is that it must provide meaningful error messages for every common error a student might make. Bugs that are easy to make and hard to track down are a surefire way to turn kids off of programming.
Python falls short in this respect. Consider this program: def plus2(realNumber): raelNumber = realNumber+2 return realNumber The problem, of course, is that when you intended to assign a value to a variable, you actually created a new one. It is very bad that a minor typo can really mess with the semantics of your code. Similar situations crop up when you intend to modify a global variable in one of your functions, but forget (or are unaware of) the global keyword, and end up creating a new local variable. Also, this problem happens all the time within objects, in which you try to assign a property, but because you misspell the property, it just creates a new property for the object. Typed languages, of course, don't have this problem, because you have to declare the types of everything you use, before you use them. But this is not the only way to solve this problem. For example, Scheme, as I recall, won't allow you to modify a variable (using set!) that has not already been bound to some initial value (using let). I think this is Python's greatest weakness as an educational language. In a lot of other ways, however, it is very nice. --Mark _______________________________________________ Edu-sig mailing list Edu-sig@python.org http://mail.python.org/mailman/listinfo/edu-sig
