Re: Noob question regarding custom method

On 11/14/2011 06:57 PM, Robert Klemme wrote:
> On Mon, Nov 14, 2011 at 1:29 PM, Sam Rose<[e-mail]>  wrote:
>> "setter" methods that have "set" in the name are far more idiomatic of
>> Java. Ruby has a different way of doing this:
>>
>> def miles=(new_miles)
>>   @miles = new_miles
>> end
>>
>> Which I know wasn't the question, I just felt like mentioning this first :)
>>
>> You're right, you could use attr_accessor (or reader or writer,
>> whichever suits the purpose best). And in this case, you probably
>> would. There's no reason not to. But some setter methods require, for
>> example, some kind of validation.
>>
>> Say if you didn't want the @miles variable to be less than 0, you could do this:
>>
>> def miles=(new_miles)
>>   if new_miles<  0
>>     raise Exception, "Miles cannot be less than 0."
>>   else
>>     @miles = new_miles
>>   end
>> end
>>
>> Is this making sense? :)
> Just a stylistic remark: I would code it like this
>
> def miles=(new_miles)
>    if new_miles<  0
>      raise Exception, "Miles cannot be less than 0."
>    end
>
>    @miles = new_miles
> end
>
> or even
>
> def miles=(new_miles)
>    raise Exception, "Miles cannot be less than 0." if new_miles<  0
>
>    @miles = new_miles
> end
>
> or
>
> def miles=(new_miles)
>    new_miles<  0 and raise Exception, "Miles cannot be less than 0."
>
>    @miles = new_miles
> end
>
> Especially with the first variant it is immediately clear what the
> main course of action is.  The exception interrupts the regular flow
> anyway so there is really no reason for the "else" branch.
>
> Kind regards
>
> robert
>
Thank you robert and sam for answering the question . It helped.

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Junayeed Ahnaf Nirjhor
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