Other Data Types

In both Algol and Fortran variables taking truth values can be declared, and Boolean or LOGICAL forms a different data type from the arithmetic data types. In PL/I the attribute concept means that there is really just one arithmetic data type, though any object of that data type will have certain attributes of scale, base and precision. Even complex quantities are part of this, since REAL or COMPLEX is simply another arithmetic attribute. As for Boolean, there is no direct equivalent at all, the nearest being a bit string of length 1. Bit strings are dealt with in section 2.5.3, since it is more convenient to discuss them after character strings (section 2.5.2). First, however, we deal briefly with the COMPLEX attribute.