From: Jari Williamsson <jari.williamsson@...>
Date: 2008-01-31T23:14:03+09:00
Subject: Re: can ik make this more beautifull?

Peter Hickman wrote:
> Jari Williamsson wrote:
>> Remco Hh wrote:
>>> nowadays i try to improve my coding style to produce nicer and beter
>>> readable code. I try to improve the following code but i dont know how.
>>>
>>> if condtion1
>>>       x=1
>>>     else
>>>       if condition2
>>>          x=2
>>>       else
>>>          if condition3
>>>            x=3
>>>         end
>>>       end
>>>       x=nill
>>>   end
>>>
>>> there are three different conditions which can not occur at the same
>>> time
>>> can i make this nicer?
>>
>> A case expression is probably the most clear alternative. The shortest 
>> is perhaps something like:
>>
>> x = condition1 ? 1 : condition2 ? 2 : 3
>>
>>
>> Best regards,
>>
>> Jari Williamsson
>>
>>
> Short it may be but this sort of code can hardly be called beautiful, I 
> have had to maintain crap like this before and the few keystrokes the 
> author saved was made up for 1000 times when someone updated it and 
> things didn't 'quite' work how they thought. Ruby allows simplicity and 
> clarity, this however is heading into obfuscation.
> 
> The better solution is to use the elsif keyword to flatten the indentation:
> 
> if (temp == 'cat')
>  x = 1
> elsif(temp == 'dog')
>  x = 2
> elsif(temp == 'banana')
>  x = 3
> else
>  x = nil
> end

But this elsif solution isn't heading for clarity either, compared to 
using a case expression:
x = case temp
         when 1 then 'cat'
         when 2 then 'dog'
         when 3 then 'banana'
         else nil
     end

In the elsif example, x appears 4 times instead of 1, temp appears 3 
times instead of 1. Apart from require an editor that support 
refactoring and the risk of typos, there will also be a performance hit 
when temp isn't matched.


Best regards,

Jari Williamsson