From: ts Date: 2002-04-25T19:45:51+09:00 Subject: Re: Numberic#prev >>>>> "P" == Paul Brannan writes: P> Perhaps posting this is not wise, but here is an implementation, with P> some examples. Maybe this will make the problem more concrete, or maybe P> it is a Pandora's box. Read it at your own risk. Well, this is not really the reverse of the algorithm for #succ. You can see it for example with "9%". With your algorithm the result is "9$", but for ruby "8%".succ is "9%" (i.e. it search first if it exist alpha-numeric character in the string and if found it make the increment on these characters.) Guy Decoux