package fri.patterns.interpreter.parsergenerator.syntax.builder.examples;
import java.io.*;
import fri.patterns.interpreter.parsergenerator.*;
import fri.patterns.interpreter.parsergenerator.syntax.Syntax;
import fri.patterns.interpreter.parsergenerator.syntax.builder.SyntaxBuilder;
import fri.patterns.interpreter.parsergenerator.parsertables.LALRParserTables;
/**
This example reads the SyntaxBuilder EBNF specification, builds
a lexer and parser from it, and parses its own specification with
these rules.
@author (c) 2002, Fritz Ritzberger
*/
public class Example
{
public static void main(String [] args) {
try {
System.out.println("Input is: "+(args.length > 0 ? args[0] : "SyntaxBuilder.syntax"));
InputStreamReader in = args.length <= 0
? new InputStreamReader(Example.class.getResourceAsStream("SyntaxBuilder.syntax"))
: new InputStreamReader(new FileInputStream(args[0]));
SyntaxBuilder builder = new SyntaxBuilder(in);
Syntax syntax = builder.getSyntax();
System.out.println("Resolved syntax rules are: ==============");
System.out.println(syntax.toString());
// now lets see if we can parse the syntax specification text with its own syntax
in = args.length <= 0
? new InputStreamReader(Example.class.getResourceAsStream("SyntaxBuilder.syntax"))
: new InputStreamReader(new FileInputStream(args[0]));
Lexer lexer = builder.getLexer();
lexer.setInput(in);
lexer.setDebug(true);
Syntax parserSyntax = builder.getParserSyntax();
ParserTables parserTables = new LALRParserTables(parserSyntax);
Parser parser = new Parser(parserTables);
boolean ok = parser.parse(lexer);
if (ok == false)
throw new Exception("Failed parsing syntax specification text!");
else
System.out.println("SyntaxBuilder succeeded parsing its own syntax specification text!");
}
catch (Exception e) {
e.printStackTrace();
}
}
}