Bertrand Meyer

Subprogram packages are groups of related subroutines used to extend the available facilities in a programming system. The results of developing several such packages for various applications are presented, with a distinction made between external and internal design criteria— what properties packages should offer to their users and the guidelines designers should follow in order to provide them. An important issue, the design of reusable software, is thus addressed, and the concept of abstract data types proposed as a desirable solution.