From: Florian Gross <flgr@...>
Date: 2005-03-24T09:39:50+09:00
Subject: Re: Credit Card Verification as an exercise

Ben Giddings wrote:

> Florian Gross wrote:
> 
>> case card_type
>>   when 'visa' then
>>     [13, 16].include?(digit_length) and number[0, 1] == "4"
>>   when 'mastercard' then
>>     digit_length == 16 and ("51" .. "55").include?(number[0, 2])
>>   when 'amex' then
>>     digit_length == 15 and %w(34 37).include?(number[0, 2])
>>   when 'discover' then
>>     digit_length == 16 and number[0, 4] == "6011"
>> end
>>
> 
> Actually, you don't need the "then"s either (and you should probably 
> have an else, even though nil is "untrue" as well)

I know, but I somehow think it looks more balanced that way. Though I 
was not sure whether to use "then" or ":" in this case -- I guess it is 
a matter of taste and not too important. :)