lojix/wam_prolog/src/main/com/thesett/aima/logic/fol/wam/machine/WAMResolvingJavaMachine.java
private String printSlot(int xi, int mode)
    {
        return ((mode == STACK_ADDR) ? "Y" : "X") + ((mode == STACK_ADDR) ? (xi - ep - 3) : xi);
    }
private String printSlot(int xi, int mode)
    {
        return ((mode == STACK_ADDR) ? "Y" : "X") + ((mode == STACK_ADDR) ? (xi - ep - 3) : xi);
    }
Pretty prints a variable allocation slot for tracing purposes.

@param  xi   The allocation slot to print.
@param  mode The addressing mode, stack or register.

@return The pretty printed slot.