* Tcl_GetStringFromObj should panic
				 * instead. */
    NULL			/* SetFromAny function; Tcl_ConvertToType
				 * should panic instead. */
};

/*
 * The [upvar]/[uplevel] level reference type. Uses the twoPtrValue field,
 * encoding the type of level reference in ptr and the actual parsed out
 * offset in ptr2.
 *
 * Uses the default behaviour throughout, and never disposes of the string
 * rep; it's just a cache type.
 */

static const Tcl_ObjType levelReferenceType = {
    "levelReference",

 *	Given a description of a procedure frame, such as the first argument
 *	to an "uplevel" or "upvar" command, locate the call frame for the
 *	appropriate level of procedure.
 *
 * Results:
 *	The return value is -1 if an error occurred in finding the frame (in
 *	this case an error message is left in the interp's result). 1 is
 *	returned if objPtr was either a number or a number preceded by "#" and
 *	it specified a valid frame. 0 is returned if objPtr isn't one of the
 *	two things above (in this case, the lookup acts as if objPtr were
 *	"1"). The variable pointed to by framePtrPtr is filled in with the
 *	address of the desired frame (unless an error occurs, in which case it
 *	isn't modified).
 *
 * Side effects:

    Tcl_Interp *interp,		/* Interpreter in which to find frame. */
    Tcl_Obj *objPtr,		/* Object describing frame. */
    CallFrame **framePtrPtr)	/* Store pointer to frame here (or NULL if
				 * global frame indicated). */
{
    register Interp *iPtr = (Interp *) interp;
    int curLevel, level, result;
    CallFrame *framePtr;
    const char *name = NULL;

    /*
     * Parse object to figure out which level number to go to.
     */

    result = 0;

    if (objPtr == NULL) {
	/* Do nothing */
    } else if (TCL_OK == Tcl_GetIntFromObj(NULL, objPtr, &level)
	    && (level >= 0)) {
	level = curLevel - level;
	result = 1;
    } else if (objPtr->typePtr == &levelReferenceType) {
	level = PTR2INT(objPtr->internalRep.twoPtrValue.ptr1);
	result = 1;
    } else {
	name = TclGetString(objPtr);
	if (name[0] == '#') {
	    if (TCL_OK == Tcl_GetInt(NULL, name+1, &level) && level >= 0) {
		TclFreeIntRep(objPtr);
		objPtr->typePtr = &levelReferenceType;
		objPtr->internalRep.twoPtrValue.ptr1 = INT2PTR(level);
		result = 1;
	    } else {
		result = -1;
	    }
	} else if (isdigit(UCHAR(name[0]))) { /* INTL: digit */
	    /*
	     * If this were an integer, we'd have succeeded already.
	     * Docs say we have to treat this as a 'bad level'  error.
	     */
	    result = -1;
	}
    }

    if (result == 0) {
	level = curLevel - 1;
	name = "1";
    }
    if (result != -1) {
	if (level >= 0) {

	    for (framePtr = iPtr->varFramePtr; framePtr != NULL;
		    framePtr = framePtr->callerVarPtr) {
		if (framePtr->level == level) {
		    *framePtrPtr = framePtr;
		    return result;
		}
	    }