Implementation of Parnas' it-ti construct in LISP
By: A.Dain Samples
Contributors: Naval Postgraduate School (U.S.)
Publisher: Naval Postgraduate School
Published: 1982
Place of publication: Monterey, California
Language: eng
Number of pages: 18
Subjects: Structured programming; LISP (Computer program language)
Description: D.L. Parnas has recently proposed (1) a new programming control structure the it-ti. This construct is a synthesis of several ideas in programming theory including iteration, conditionals, and Dijkstra's guards (2) It has been implemented in a LISP interpreter (8) as a more structured replacement for the traditional prog construct. Several programming examples are given that compare the use of the it-ti with the more conventional programming constructs. These examples will also show that the it-ti fails to satisfy several criteria for programming constructs including manageability and visibility. An appendix to this report contains an extension of Dijkstra's concept of the 'weakest precondition' to the it-ti. (Author)
Notes: "NPS52-82-005"--Cover.

"March 1982"--Cover

Title from cover.

"Prepared for: Chief of Naval Research, Arlington, VA 22217."

Includes bibliographical references (p. 17).

"Approved for public release; distribution is unlimited"--Cover.

Technical report; 1982.

Supported in part by the Foundation Research Program of the Naval Postgraduate School with funds provided by the Chief of Naval Research. 61152N; RR000-01-10; N0001482WR20043.

ck/ 4/15/09.