Building Parsers with Java™

13.7. Proofs

As mentioned, this chapter covers many of the same topics as Chapter 12, “Engines,” although a few differences arise when you implement a language. For example, the engine accepts any object as a functor, whereas Logikus allows only lowercase strings, quoted strings, or numbers. The engine accepts any string as the name of a variable, whereas Logikus variable names must begin with a capital letter and may not contain whitespace. Because of these subtle differences, an explanation of Logikus is a somewhat different discussion than an explanation of the engine. However, on the topic of proofs, Logikus behaves exactly as the engine does. As a result, this section covers the same information as Section 12.7, “Proofs.” If you have read ...