From: Paul Van Delst <Paul.vanDelst@...>
Date: 2006-07-06T23:52:55+09:00
Subject: Re: newbie Q: conditional object creation

Marcin Miel��y��ski wrote:
> Paul Van Delst wrote:
> 
>> Hello,
>>
>> The subject line may be confusing as I don't know the correct 
>> terminology, so apologies in advance.
>>
>> I'm want to be able to create objects, but I want the object creation 
>> to only proceed if the values passed to the init method are in a valid 
>> list. E.g.:
>>
>> class MyObj
>>   VALID_NAMES=['bananas','dog','water']
>>   attr_reader :name, :value
>>   def initialize(name,value)
>>     i=VALID_NAMES.index(name)
>>     if i then
>>       @name,@value=name,value
>>     else
>>       @name,@value=nil
>>     end
>>   end
>> end
>>
>> This sorta does what I want, but looks clunky, ugly and quite 
>> un-ruby-ish. Is there a better way (idiom?) to achieve this sort of 
> 
> just:
> 
> @name,@value=name,value if VALID_NAMES.index(name)

Excellent! Thanks very much.

cheers,

paulv

-- 
Paul van Delst             Ride lots.
CIMSS @ NOAA/NCEP/EMC               Eddy Merckx