Introduction to Compiler Construction in a Java World

Lexical Analysis 39

Example. The reserved words may be described simply by listing them. For example,

abstract

| b oolean

| char

.

.

.

| while

Likewise for operators. For example,

=

| ==

| >

.

.

.

| *

Identifiers are easily described; for example,

([a- zA -Z ] | _ | $ )([a -zA - Z0 -9] | _ | $ )*

which is to say, an identifier begins with a letter, an underscore, or a dollar sign, followed

by zero or more letters, digits, underscores, and dollar signs.

A full description of the lexical syntax for j-- may be found in Appendix B. In the next

section, we formalize state transition diagrams.

2.4 Finite State Automata

It turns out that for any language described by a regular ...