package com.creativewidgetworks.goldparser.simple2;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import com.creativewidgetworks.goldparser.engine.ParserException;
import com.creativewidgetworks.goldparser.parser.GOLDParser;
import com.creativewidgetworks.goldparser.util.FormatHelper;
/**
* An interpreter for the Simple2 demonstration language that comes
* with the GOLD Parser. Source files can be executed and parse
* trees can be generated from the input stream.
*
* @author Ralph Iden (http://www.creativewidgetworks.com)
* @version 5.0.0
*/
public class Simple2 {
private static final String RESOURCE_FILE = "simple2/simple2";
/**
* Formats rule handler messages using the simple2.properties resource file
* @param message key (e.g., error.syntax)
* @param parameters that will be inserted into any message placeholder entries (0}...
* @return formated string.
*/
public static String formatMessage(String message, Object... parameters) {
return FormatHelper.formatMessage(RESOURCE_FILE, message, parameters);
}
/*----------------------------------------------------------------------------*/
/**
* Executes a Simple2 program
* @param sourceCode to interpret
* @param wantTree true if the parse tree should be generated
* @return parse tree if generate parse tree open is set
*/
public String executeProgram(String sourceCode, boolean wantTree) {
// Use the compiled grammar file inside the jar
GOLDParser parser = new GOLDParser(
getClass().getResourceAsStream("/simple2/Simple2.cgt"), // compiled grammar table
"com.creativewidgetworks.goldparser.simple2", // rule handler package
true); // trim reductions
// Controls whether or not a parse tree is returned or the program executed.
parser.setGenerateTree(wantTree);
String tree = null;
try {
// Parse the source statements to see if it is syntactically correct
boolean parsedWithoutError = parser.parseSourceStatements(sourceCode);
// Holds the parse tree if setGenerateTree(true) was called
tree = parser.getParseTree();
// Either execute the code or print any error message
if (parsedWithoutError) {
parser.getCurrentReduction().execute();
} else {
System.out.println(parser.getErrorMessage());
}
} catch (ParserException e) {
System.out.println(e.getMessage());
e.printStackTrace();
}
return tree;
}
/*----------------------------------------------------------------------------*/
/**
* Load a source file to be interpreted by Simple2.
* @param filename of Simple2 source file
* @return source code to be interpreted
* @throws IOException
*/
public String loadSourceFile(String filename) throws IOException {
File file = new File(filename);
FileInputStream fis = new FileInputStream(file);
byte[] buf = new byte[(int)file.length()];
fis.read(buf);
fis.close();
return new String(buf);
}
/*----------------------------------------------------------------------------*/
public static void main(String[] args) throws Exception {
if (args.length > 0) {
Simple2 parser = new Simple2();
String source = parser.loadSourceFile(args[0]);
boolean wantTree = args.length > 1 && args[1].equalsIgnoreCase("-tree");
String tree = parser.executeProgram(source, wantTree);
if (wantTree) {
System.out.println(tree);
}
} else {
System.out.println("Usage: java -jar simple2.jar <sourcefile> [-tree]");
}
}
}