/*
 * ForCmd.java
 *
 * Copyright (c) 1997 Cornell University.
 * Copyright (c) 1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and
 * redistribution of this file, and for a DISCLAIMER OF ALL
 * WARRANTIES.
 * 
 * RCS: @(#) $Id: ForCmd.java,v 1.1.1.1 1998/10/14 21:09:19 cvsadmin Exp $
 *
 */

package tcl.lang;

/**
 * This class implements the built-in "for" command in Tcl.
 */

class ForCmd implements Command {
    /*
     * This procedure is invoked to process the "for" Tcl command.
     * See the user documentation for details on what it does.
     *
     * @param interp the current interpreter.
     * @param argv command arguments.
     * @exception TclException if script causes error.
     */

    public void cmdProc(Interp interp, TclObject argv[])
	    throws TclException {
	if (argv.length != 5) {
	    throw new TclNumArgsException(interp, 1, argv, 
		    "start test next command");
	}

	TclObject start   = argv[1];
	String test       = argv[2].toString();
	TclObject next    = argv[3];
	TclObject command = argv[4];

	boolean done = false;
	try {
	    interp.eval(start, 0);
	} catch (TclException e) {
	    interp.addErrorInfo("\n    (\"for\" initial command)");
	    throw e;
	}

	while (!done) {
	    if (!interp.expr.evalBoolean(interp, test)) {
		break;
	    }

	    try {
		interp.eval(command, 0);
	    } catch (TclException e) {
		switch (e.getCompletionCode()) {
		case TCL.BREAK:
		    done = true;
		    break;
			
		case TCL.CONTINUE:
		    break;

		case TCL.ERROR:
		    interp.addErrorInfo("\n    (\"for\" body line " +
				interp.errorLine + ")");
		    throw e;

		default:
		    throw e;
		}
	    }

	    if (!done) {
		try {
		    interp.eval(next, 0);
		} catch (TclException e) {
		    switch (e.getCompletionCode()) {
		    case TCL.BREAK:
			done = true;
			break;
			
		    case TCL.CONTINUE:
			break;

		    default:
			interp.addErrorInfo(
				"\n    (\"for\" loop-end command)");
			throw e;
		    }
		}
	    }
	}

	interp.resetResult();
    }
}