2.9 The T3X Object Model

Like many popular object oriented languages, T3X is a hybrid language. A hybrid language is a language incorporating (at least) two different paradigms. T3X uses the object oriented approach at a rather abstract level and the procedural approach at the lower levels. For example, numbers are no objects in T3X and adding numbers is not done by sending messages. In a purely object oriented language, the term

5 + 7

would be interpreted as send the message '+' with the argument '7' to the object '5'. In a procedural language, however, adding numbers is done by combining factors and operators to form expressions. Interpreting numbers as objects and expressions as messages makes no sense in a procedural language, since numbers and operators are not implemented this way. [In T3X, classes are normally not used to form data types, but to implement instantiatable (and therefore re-usable) libraries, so this aspect of T3X is more like early ADA rather than Java or C++.] There are many hybrid languages employing both the procedural and object oriented approach. For example, C++, Java, and ObjectPascal fit in this category. A well-known member of the family of purely object oriented languages is Smalltalk.