unsigned int nodesAvailable = 64; /* Initial size of the storage array. This
				 * value establishes a minimum tree memory
				 * cost of only about 1 kibyte, and is large
				 * enough for most expressions to parse with
				 * no need for array growth and
				 * reallocation. */
    unsigned int nodesUsed = 0;	/* Number of OpNodes filled. */
    size_t scanned = 0;		/* Capture number of byte scanned by parsing
				 * routines. */
    int lastParsed;		/* Stores info about what the lexeme parsed
				 * the previous pass through the parsing loop
				 * was. If it was an operator, lastParsed is
				 * the index of the OpNode for that operator.
				 * If it was not an operator, lastParsed holds
				 * an OperandTypes value encoding what we need

				 * message where the error location is
				 * reported, this "mark" substring is inserted
				 * into the string being parsed to aid in
				 * pinpointing the location of the syntax
				 * error in the expression. */
    int insertMark = 0;		/* A boolean controlling whether the "mark"
				 * should be inserted. */
    const unsigned limit = 25;	/* Portions of the error message are
				 * constructed out of substrings of the
				 * original expression. In order to keep the
				 * error message readable, we impose this
				 * limit on the substring size we extract. */

    TclParseInit(interp, start, numBytes, parsePtr);

	 * Add a detailed quote from the bad expression, displaying and
	 * sometimes marking the precise location of the syntax error.
	 */

	Tcl_AppendPrintfToObj(msg, "\nin expression \"%s%.*s%.*s%s%s%.*s%s\"",
		((start - limit) < parsePtr->string) ? "" : "...",
		((start - limit) < parsePtr->string)
			? (int) (start - parsePtr->string) : (int)limit - 3,
		((start - limit) < parsePtr->string)
			? parsePtr->string : start - limit + 3,
		(scanned < limit) ? scanned : limit - 3, start,
		(scanned < limit) ? "" : "...", insertMark ? mark : "",
		(start + scanned + limit > parsePtr->end)
			? (int) (parsePtr->end - start) - scanned : limit-3,
		start + scanned,

	/*
	 * Finally, place context information in the errorInfo.
	 */

	numBytes = parsePtr->end - parsePtr->string;
	Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
		"\n    (parsing expression \"%.*s%s\")",
		(numBytes < (int)limit) ? numBytes : (int)limit - 3,
		parsePtr->string, (numBytes < (int)limit) ? "" : "..."));
	if (errCode) {
	    Tcl_SetErrorCode(interp, "TCL", "PARSE", "EXPR", errCode,
		    subErrCode, NULL);
	}
    }

    return TCL_ERROR;