#define BAREWORD	3	/* Ambigous. Resolves to BOOLEAN or to
				 * FUNCTION or a parse error according to
				 * context and value. */
#define INCOMPLETE	4	/* A parse error. Used only when the single
				 * "=" is encountered.  */
#define INVALID		5	/* A parse error. Used when any punctuation
				 * appears that's not a supported operator. */
#define COMMENT		6	/* Comment. Lasts to end of line or end of
				 * expression, whichever comes first. */

/* Leaf lexemes */

#define NUMBER		(LEAF | 1)
				/* For literal numbers */
#define SCRIPT		(LEAF | 2)
				/* Script substitution; [foo] */

	INVALID		/* DC4 */,	INVALID		/* NAK */,
	INVALID		/* SYN */,	INVALID		/* ETB */,
	INVALID		/* CAN */,	INVALID		/* EM */,
	INVALID		/* SUB */,	INVALID		/* ESC */,
	INVALID		/* FS */,	INVALID		/* GS */,
	INVALID		/* RS */,	INVALID		/* US */,
	INVALID		/* SPACE */,	0		/* ! or != */,
	QUOTED		/* " */,	INVALID		/* # */,
	QUOTED		/* " */,	0		/* # */,
	VARIABLE	/* $ */,	MOD		/* % */,
	0		/* & or && */,	INVALID		/* ' */,
	OPEN_PAREN	/* ( */,	CLOSE_PAREN	/* ) */,
	0		/* * or ** */,	PLUS		/* + */,
	COMMA		/* , */,	MINUS		/* - */,
	0		/* . */,	DIVIDE		/* / */,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0,			/* 0-9 */

	 * Use context to categorize the lexemes that are ambiguous.
	 */

	if ((NODE_TYPE & lexeme) == 0) {
	    int b;

	    switch (lexeme) {
	    case COMMENT:
		start += scanned;
		numBytes -= scanned;
		continue;
	    case INVALID:
		msg = Tcl_ObjPrintf("invalid character \"%.*s\"",
			scanned, start);
		errCode = "BADCHAR";
		goto error;
	    case INCOMPLETE:
		msg = Tcl_ObjPrintf("incomplete operator \"%.*s\"",

    int numBytes,		/* Number of bytes in string. */
    unsigned char *lexemePtr,	/* Write code of parsed lexeme to this
				 * storage. */
    Tcl_Obj **literalPtr)	/* Write corresponding literal value to this
				   storage, if non-NULL. */
{
    const char *end;
    int scanned;
    int scanned, size;
    Tcl_UniChar ch = 0;
    Tcl_Obj *literal = NULL;
    unsigned char byte;

    if (numBytes == 0) {
	*lexemePtr = END;
	return 0;
    }
    byte = UCHAR(*start);
    if (byte < sizeof(Lexeme) && Lexeme[byte] != 0) {
	*lexemePtr = Lexeme[byte];
	return 1;
    }
    switch (byte) {
    case '#':
	/*
	 * Scan forward over the comment contents.
	 */
	for (size = 0; byte != '\n' && byte != 0 && size < numBytes; size++) {
	    byte = UCHAR(start[size]);
	}
	*lexemePtr = COMMENT;
	return size - (byte == '\n');

    case '*':
	if ((numBytes > 1) && (start[1] == '*')) {
	    *lexemePtr = EXPON;
	    return 2;
	}
	*lexemePtr = MULT;
	return 1;