From: Marnen Laibow-Koser <marnen@...>
Date: 2009-12-11T02:49:19+09:00
Subject: Re: human-readable listing of array elements

Benoit Daloze wrote:
> Hi,
> 
> 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.

> 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.

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. :)

> 
> Anyway, I'm wondering how case manage the comma(,), is it acting like a 
> OR
> on each of the elements? I thought first to Array#=== but that isn't
> defined. So, is it sort of syntactic sugar ?
> 
> 2009/12/10 Robert Klemme <shortcutter@googlemail.com>

Best,
-- 
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
Posted via http://www.ruby-forum.com/.