From: Robert Klemme <shortcutter@...>
Date: 2009-12-11T07:10:07+09:00
Subject: Re: human-readable listing of array elements

On 12/10/2009 06:49 PM, Marnen Laibow-Koser wrote:
> Benoit Daloze wrote:

>> As written in "Programming Ruby 1.9",
>> You can really use case as if ... elsif ... else ... end
>>
>> So, in our case:
>>
>> if self.size <= 1
>>   return self.to_s
>> elsif self.size == 2
>>   return self.join " #{conjunction} "
>> else
>>   array = self.dup
>>   array[-1] = [conjunction, array[-1]].join ' '
>>   array.join separator # proper English usage has comma before 'and'
>> end
>>
>> becomes:
>>
>> case
>> when self.size <= 1
>>   return self.to_s
>> when self.size == 2
>>   return self.join " #{conjunction} "
>> else
>>   array = self.dup
>>   array[-1] = [conjunction, array[-1]].join ' '
>>   array.join separator # proper English usage has comma before 'and'
>> end
>>
> 
> Thanks, I had forgotten about that too.

Me, too.

>> Well, that's not especially better I think, but it looks cool and a 
>> little
>> less 'procedural' to me.
> 
> It's no less procedural, and in fact it uses another line of code for no 
> advantage that I can see.

The advantage for me is that "case" conveys a different notion: I am 
reminded of SQL's case which is an expression, i.e. you get a single 
value out of several based on conditions after "where".  "if elsif else 
end" is more about executing different procedural sequences.  The 
difference is less technical and more informal.

> If you truly want this to look less procedural, I think you'd need to 
> somehow implement a polymorphic dispatch based on Array.size...but let's 
> not go there. :)

Not too difficult either, let's see....

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/