int exp2RK(ExpDesc e) {
		this.exp2val(e);
		switch (e.k) {
		case LexState.VKNUM:
		case LexState.VTRUE:
		case LexState.VFALSE:
		case LexState.VNIL: {
			if (this.nk <= MAXINDEXRK) { /* constant fit in RK operand? */
				e.info = (e.k == LexState.VNIL) ? this.nilK()
						: (e.k == LexState.VKNUM) ? this.numberK(e.nval())
								: this.boolK((e.k == LexState.VTRUE));
				e.k = LexState.VK;
				return RKASK(e.info);
			} else
				break;
		}
		case LexState.VK: {
			if (e.info <= MAXINDEXRK) /* constant fit in argC? */
				return RKASK(e.info);
			else
				break;
		}
		default:
			break;
		}
		/* not a constant in the right range: put it in a register */
		return this.exp2anyreg(e);
	}