Chapter 3. Using Bison

The previous chapter concentrated on flex alone. In this chapter we turn our attention to bison, although we use flex to generate our lexical analyzers. Where flex recognizes regular expressions, bison recognizes entire grammars. Flex divides the input stream into pieces (tokens), and then bison takes these pieces and groups them together logically. In this chapter we’ll finish the desk calculator we started in Chapter 1, starting with simple arithmetic and then adding built-in functions, user variables, and finally user-defined functions.