Re: Noob question regarding custom method

"setter" methods that have "set" in the name are far more idiomatic of
Java. Ruby has a different way of doing this:

def miles=3D(new_miles)
  @miles =3D 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=3D(new_miles)
  if new_miles < 0
    raise Exception, "Miles cannot be less than 0."
  else
    @miles =3D new_miles
  end
end

Is this making sense? :)

On 14 November 2011 11:51, Junayeed Ahnaf Nirjhor
<[e-mail]> wrote:
> Hello,
>
> I am still learning ruby. My question is, often we see things like this:
>
> =A0def set_miles(miles)
> =A0 =A0@miles =3D miles
> =A0end
>
> Here, we're defining a custom method set_miles , then passing it an argum=
ent
> (what's the reason of doing so?), then we're setting the instance variabl=
e
> @miles to a local variable miles, why's that for? I know I can use
> attr_accessor but things like this occurs in various place. What's the po=
int
> of doing this?
>
>
> I know I sound funny but i can't understand. Any help would be much much
> much appreciated.
> --
> Junayeed Ahnaf Nirjhor
> /Doing this and that/
> http://twitter.com/nirjhor
>