Program Specification Applied to a Text Formatter

Presentation of the fonnal specification of a small text formatter illustrates an approach to the construction of formal specifications. The key features of this approvach are described, and their beneficial influence on the construction and organization of specifications of tasks, especially those for which no concise descriptions are possible, are discussed. The intent is that in addition to serving as formal descriptions of tasks, such specifications will be of use in the processes of verification, development, and maintenance of their implementations.