/*
 * SubstCmd.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: SubstCmd.java,v 1.1.1.1 1998/10/14 21:09:19 cvsadmin Exp $
 *
 */

package tcl.lang;

import java.util.*;

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

class SubstCmd implements Command {
    static final private String validCmds[] = {
	"-nobackslashes",
	"-nocommands",
	"-novariables"
    };

    static final int OPT_NOBACKSLASHES		= 0;
    static final int OPT_NOCOMMANDS		= 1;
    static final int OPT_NOVARS			= 2;

    /**
     * This procedure is invoked to process the "subst" Tcl command.
     * See the user documentation for details on what it does.
     *
     * @param interp the current interpreter.
     * @param argv command arguments.
     * @exception TclException if wrong # of args or invalid argument(s).
     */

    public void cmdProc(Interp interp, TclObject argv[])
	    throws TclException {
	int currentObjIndex, len, i;
	int objc = argv.length - 1;
	boolean doBackslashes = true;
	boolean doCmds = true;
	boolean doVars = true;
	String result = "";
	String s;
	char c;

	for (currentObjIndex = 1; currentObjIndex < objc; currentObjIndex++) {
	    if (!argv[currentObjIndex].toString().startsWith("-")) {
		break;
	    }
	    int opt = TclIndex.get(interp, argv[currentObjIndex], 
		    validCmds, "switch", 0);
	    switch (opt) {
	        case OPT_NOBACKSLASHES:
		    doBackslashes = false;
		    break;
	        case OPT_NOCOMMANDS:
		    doCmds = false;
		    break;
	        case OPT_NOVARS:
		    doVars = false;
		    break;
	        default:
		    throw new TclException(interp, 
			    "SubstCmd.cmdProc: bad option " + opt 
			    + " index to cmds");
	    }
	}
	if (currentObjIndex != objc) {
	    throw new TclNumArgsException(interp, currentObjIndex, argv, 
		    "?-nobackslashes? ?-nocommands? ?-novariables? string");
	}

	/*
	 * Scan through the string one character at a time, performing
	 * command, variable, and backslash substitutions.
	 */
	
	s = argv[currentObjIndex].toString();
	len = s.length();
	i = 0;
	while (i < len) {
	    c = s.charAt(i);
	    
	    if ((c == '[') && doCmds) {
		ParseResult res;
		try {
		    interp.evalFlags = Parser.TCL_BRACKET_TERM;
		    interp.eval(s.substring(i + 1, len));
		    res = new ParseResult(interp.getResult(), 
			    i + interp.termOffset);		    
		} catch (TclException e) {
		    i = e.errIndex + 1;
		    throw e;
		}
		i = res.nextIndex + 2;
		result = result + res.value.toString();
		
	    } else if (c == '\r') {
		/*
		 * (ToDo) may not be portable on Mac
		 */
		
		i++;
	    } else if ((c == '$') && doVars) {
		ParseResult vres = Parser.parseVar(interp,
			s.substring(i, len));
		i += vres.nextIndex;
		result = result + vres.value.toString();
	    } else if ((c == '\\') && doBackslashes) {
		BackSlashResult bs = interp.backslash(s, i, len);
		i = bs.nextIndex;
		if (bs.isWordSep) {
		    break;
		} else {
		    result = result + bs.c;
		}
	    } else {
		result = result + c;
		i++;
	    }
	    if (i >= len) {
		break;
	    }
	}

	interp.setResult(result);
    }
}