Language Implementation Patterns

Chapter 2Basic Parsing Patterns

Language recognition is a critical step in just about any language application. To interpret or translate a phrase, we first have to recognize what kind of phrase it is (sentences are made up of phrases). Once we know that a phrase is an assignment or function call, for example, we can act on it. To recognize a phrase means two things. First, it means we can distinguish it from the other constructs in that language. And, second, it means we can identify the elements and any substructures of the phrase. For example, if we recognize a phrase as an assignment, we can identify the variable on the left of the = and the expression substructure on the right. The act of recognizing a phrase by computer is called parsing ...