import java.net.*;
import java.io.*;


/** 
 * FakeFril.java
 *
 * Title:			FakeFril
 *
 * Description	
 *	Tutorial example using high level Fril Foreign Language Interface functions.
 * This is a simple tty-based app, which fakes a normal tty Fril. Input and 
 * output are connected to stdin and stdout respectively. One difference from
 * the genuine article is that lines read from the BufferedReader are not 
 * terminated by a carriage return - this may be important (for example) if the trace
 * package is run. 
 * Limited testing has been carried out, but the system may not be stable under error
 * conditions, interrupts, etc and under no circumstances should it be used for controlling
 * nuclear submarines.
 * Error checking is very limited.
 *
 * @author T. P. Martin
 * @date June 2001
 * @version 1.0b1
 */

public class FakeFril {

private static JFril aFril;		// the embedded Fril object

private static final String THISCLASS = "FakeFril::";
private static final String PROMPT = "prompt >";
private static final String CREATIONDATE = "07-06-01";

// this is a query run when the system is created - replace it as necessary
private static final String INITQUERY = "?((pp initQuery)(getenv frlib X)(p Fril library at X)(pp))";


public static void main(String[] args) throws IOException {

PrintWriter out ;			// handles the output from Fril
BufferedReader stdIn ;		// handles the input for Fril
int ret;					// return value from Fril execution

System.out.println(THISCLASS + " starting up version of " + CREATIONDATE); 

	try {
		out = new PrintWriter(System.out, true);
	 	stdIn = new BufferedReader(new InputStreamReader(System.in));
		System.out.println(THISCLASS + "about to create aFril");
	 	aFril = new JFril(out, INITQUERY);		// create a JFril object and run INITQUERY
 		if (aFril == null)
                    System.out.println(THISCLASS + "couldn't create aFril");                
                else
                    System.out.println(THISCLASS + "loaded native Fril version" + aFril.jFrilGetVersion());
               
               out.flush();            
	
    out.print(THISCLASS + PROMPT);
    out.flush();
	
    if(aFril != null)
    { 
    	while (aFril.jFrilGetStatus())
	{
	if( stdIn.ready() )			// something to give to Fril
	{
                ret = aFril.jFrilExecuteFril(stdIn);	// pass it on and let Fril execute
		switch (ret)
                {
                case JFril.JFRILSUCCEEDED:
                    out.println("yes");
                    break;
                case JFril.JFRILFAILED:
                    out.println("no");
                    break;		
                case JFril.JFRILTERMINATED:
                    out.println("Fril has terminated");
                    break;		
                default:
                    out.println(THISCLASS + "unexpected return value from jFrilExecuteFril " + ret);
                }
                out.print(THISCLASS + PROMPT );
                out.flush();
            }

	}
        out.print(THISCLASS + "> aFril status false <");
    }
    out.close();
    stdIn.close();
    } catch (IOException e) {
        System.err.println(THISCLASS + "IO Error " + e);
        System.exit(1);
    }
        System.exit(0);
}



}