From: Eleanor McHugh <eleanor@...>
Date: 2008-05-07T00:58:20+09:00
Subject: Re: I know this code is not very 'ruby'

On 6 May 2008, at 15:48, Robert Klemme wrote:
> 2008/5/6 Eleanor McHugh <eleanor@games-with-brains.com>:
>> Remember that case statements are expressions, hence:
>>
>> def discount(discount_category)
>>        case discount_category
>>        when 1 :        40
>>        when 2 :        100
>>        when 3 :        160
>>        else            discount_out
>
> I guess this should read
>
> else 0

That's what happens when I write code before my second cup of tea of  
the morning ;)

> I was going to suggest something similar, i.e. use more verbose
> category "names".  If categories are read from somewhere they could be
> mapped on input.
>
> But, as Todd also mentions, this cries for a Hash.  With a Hash method
> #discount is basically superfluous.
>
> DISCOUNT = Hash.new(0).update(
>  :friend => 40,
>  :vet => 100,
>  :super_vet => 160
> ).freeze
>
> Then a method call essentially becomes
>
> DISCOUNT[:foo]
>
> instead of
>
> discount :foo

I'd probably use a Hash as well for a trivial mapping like this, but I  
thought it was more instructive to just abolish the unnecessary  
variable seeing as Tim clearly didn't realise that Ruby uses a case  
expression rather than a case statement. And of course if the discount  
were to rely on several parameters then the case expression form might  
well be much easier to maintain.


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason