NOT.4:4.5 - Challenge the condition most likely to fail in reuse

Change a relevant binding, assumption, input class or intended observation. Repeat the affected transformation and reading, or explain why the rule no longer applies. Test the rule’s boundary rather than adding an unrelated difficult example. Sections :5.1 and :5.3 show changed bindings and local assumptions.

If a transformation is to run automatically, give CMP.12 the admitted expression structures, matching and replacement rules, and observations to preserve. An algorithm for repeatedly applying rules also needs a search strategy and a stopping condition. The availability of several valid rewrites does not imply that applying them in arbitrary order terminates or finds the most useful form.