Including Non-functional Issues in Anna/Ada Programs for Automatic Implementation Selection

We present an enrichment of the Anna specification language for Ada aimed at dealing not only with functional specification of packages but also with non-functional information about them. By non-functional information we mean information about efficiency, reliability and, in general, any software attribute measuring somehow the quality of software (perhaps in a subjective manner). We divide this information into three kinds: definition of non-functional properties, statement of non-functional behaviour and statement of non-functional requirements; like Anna annotations, all of this information appears in Ada packages and package bodies and their syntax is close to Ada constructs. Non-functional information may be considered not only as valuable comments, but also as an input for an algorithm capable of selecting the "best" package body for every package definition in a program, the "best" meaning the one that fits the set of non-functional requirements of the package in the program.