Robert B. Terwilliger, Roy H. Campbell

Research output: Chapter in Book/Report/Conference proceedingConference contribution


PLEASE is an executable specification language that supports program development by incremental refinement. The authors present the PLEASE specification for a small library database. PLEASE is part of the ENCOMPASS environment, that provides automated support for all aspects of the software development process. Software components are first specified using a combination of conventional programming languages and predicate logic. These abstract components are then incrementally refined into components in an implementation language. Each refinement is verified before another is applied; therefore, the final components produced by the development satisfy the original specifications. PLEASE allows a procedure or function to be specified with pre- and postconditions written using Horn clauses. PLEASE specifications may be used in proofs of correctness. They may also be transformed into prototypes that use Prolog to execute pre- and postconditions.

Original languageEnglish (US)
Title of host publicationUnknown Host Publication Title
Number of pages8
ISBN (Print)0818607696
StatePublished - Jan 1 1987

ASJC Scopus subject areas

  • Engineering(all)

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  • Cite this

    Terwilliger, R. B., & Campbell, R. H. (1987). PLEASE: A LANGUAGE FOR INCREMENTAL SOFTWARE DEVELOPMENT. In Unknown Host Publication Title (pp. 249-256). IEEE.