Experiences with PiZA, an Animator for Z

Large Z specifications require testing if they are to be at all credible and translation to Prolog provides one means of doing this. Experience with PiZA (Prolog Z Animator), a system designed to carry out this translation automatically, is described. The paper gives a brief description of the principles of the translation with some practical details of using PiZA. Experience in animating large specifications of about the size of a small compiler is discussed in terms of the performance, the problems presented by the form of the Prolog translation, the processing of input and output values and the use of diagnostics. The paper concludes with a discussion of the use of Z as a design language.