Getting the next and previous values

The two methods, pred and succ, correspondingly return the previous and the next values for integer arguments:

say 42.pred; # 41
say 42.succ; # 43

This method also works with non-integer values, when they add or subtract 1, as shown in the next fragment: 

say pi.pred;    # 2.14159265358979
say (3/4).succ; # 1.75

The names of the methods come from the words predecessor and successor.