/*
 * CaseCmd.java
 *
 * 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: CaseCmd.java,v 1.1.1.1 1998/10/14 21:09:18 cvsadmin Exp $
 *
 */

package tcl.lang;

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

class CaseCmd implements Command {
    /**
     * Executes a "case" statement. See Tcl user
     * documentation for details.
     *
     * @param interp the current interpreter.
     * @param argv command arguments.
     * @exception TclException If incorrect number of arguments.
     */

    public void cmdProc(Interp interp, TclObject argv[])
	    throws TclException {
	if (argv.length < 3) {
	    throw new TclNumArgsException(interp, 1, argv, 
		    "string ?in? patList body ... ?default body?");
        }

	int i, result;
	int body;
	TclObject caseArgv[];
	String string;

	string = argv[1].toString();
	caseArgv = argv;
	body = -1;

	if (argv[2].toString().equals("in")) {
	    i = 3;
	} else {
	    i = 2;
	}

	/*
	 * If all of the pattern/command pairs are lumped into a single
	 * argument, split them out again.
	 */

	if (argv.length - i == 1) {
	    caseArgv = TclList.getElements(interp, argv[i]);
	    i = 0;
	}

	match_loop: {
	    for (; i < caseArgv.length; i += 2) {
		int j;

		if (i == (caseArgv.length-1)) {
		    throw new TclException(interp,
			    "extra case pattern with no body");
		}

		/*
		 * Check for special case of single pattern (no list) with
		 * no backslash sequences.
		 */

		String caseString = caseArgv[i].toString();
		int len = caseString.length();
		for (j=0; j<len; j++) {
		    char c = caseString.charAt(j);
		    if (Character.isWhitespace(c) || (c == '\\')) {
			break;
		    }
		}
		if (j == len) {
		    if (caseString.equals("default")) {
			body = i+1;
		    }
		    if (Util.stringMatch(string, caseString)) {
			body = i+1;
			break match_loop;
		    }
		    continue;
		}

		/*
		 * Break up pattern lists, then check each of the patterns
		 * in the list.
		 */

		int numPats = TclList.getLength(interp, caseArgv[i]);
		for (j = 0; j < numPats; j++) {
		    if (Util.stringMatch(string, TclList.index(interp,
			    caseArgv[i], j).toString())) {
			body = i+1;
			break match_loop;
		    }
		}
	    }
	}

	if (body != -1) {
	    try {
		interp.eval(caseArgv[body], 0);
	    } catch (TclException e) {
		if (e.getCompletionCode() == TCL.ERROR) {
		    interp.addErrorInfo("\n    (\"" + caseArgv[body-1] + 
			    "\" arm line " + interp.errorLine + ")");
		}
		throw e;
	    }
	}
    }
}