The Definitive ANTLR 4 Reference, 2nd Edition

Integrating a Generated Parser into a Java Program

Once we have a good start on a grammar, we can integrate the ANTLR-generated code into a larger application. In this section, we’ll look at a simple Java main that invokes our initializer parser and prints out the parse tree like TestRig’s -tree option. Here’s a boilerplate Test.java file that embodies the overall recognizer data flow we saw in ​Let’s Get Meta!​:

starter/Test.java

// import ANTLR's runtime libraries
import org.antlr.v4.runtime.*;
import org.antlr.v4.runtime.tree.*;

public class Test {
    public static void main(String[] args) throws Exception {
        // create a CharStream that reads from standard input
        ANTLRInputStream input = new ANTLRInputStream(System.in); ...