/*
 * ForeachCmd.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: ForeachCmd.java,v 1.1.1.1 1998/10/14 21:09:20 cvsadmin Exp $
 *
 */

package tcl.lang;

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

class ForeachCmd implements Command {
    /**
     * This procedure is invoked to process the "foreach" 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 < 4 || (argv.length % 2) != 0) {
	    throw new TclNumArgsException(interp, 1, argv, 
		    "varList list ?varList list ...? command");
	}

	/*
	 *
	 * foreach {n1 n2} {1 2 3 4} {n3} {1 2} {puts $n1-$n2-$n3}
	 *	name[0] = {n1 n2}	value[0] = {1 2 3 4}
	 *	name[1] = {n3}		value[0] = {1 2}
	 */

	TclObject name[]  = new TclObject[(argv.length - 2) / 2];
	TclObject value[] = new TclObject[(argv.length - 2) / 2];

	int c, i, j, base;
	int maxIter = 0;
	String result;
	TclObject command = argv[argv.length-1];
	boolean done = false;

	for (i=0; i<argv.length-2; i+=2) {
	    int x = i/2;
	    name[x]  = argv[i+1];
	    value[x] = argv[i+2];

	    int nSize = TclList.getLength(interp, name[x]);
	    int vSize = TclList.getLength(interp, value[x]);

	    if (nSize == 0) {
		throw new TclException(interp, "foreach varlist is empty");
	    }

	    int iter = (vSize + nSize - 1) / nSize;
	    if (maxIter < iter) {
		maxIter = iter;
	    }
	}
	
	for (c=0; !done && c<maxIter; c++) {
	    /*
	     * Set up the variables
	     */

	    for (i=0; i<argv.length-2; i+=2) {
		int x = i/2;
		int nSize = TclList.getLength(interp, name[x]);
		base = nSize * c;
		for (j=0; j<nSize; j++) {
		    /**
		     * Test and see if the name variable is an array.
		     */

		    Var var = (Var)interp.varFrame.varTable.
                            get(name[x].toString());
		    if ((var != null) && ((var.flags & Var.ARRAY) != 0)) {
		        throw new TclException(interp, 
			        "couldn't set loop variable: \"" +
				name[x] + "\"");
		    }

		    try {
			if (base + j >= TclList.getLength(interp, value[x])) {
			    interp.setVar(TclList.index(interp, name[x], j),
				    TclString.newInstance(""), 0);
			} else {
			    interp.setVar(TclList.index(interp, name[x], j),
				    TclList.index(interp, value[x], base + j),
				    0);
			}
		    } catch (TclException e) {
			throw new TclException(interp, 
				"couldn't set loop variable: \"" + 
				TclList.index(interp, name[x], j) + "\"");
		    }
		}
	    }

	    /*
	     * Execute the script
	     */

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

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

		default:
		    throw e;
		}
	    }
	}

	interp.resetResult();
    }
}