Yeah of course the preference is not to have setters... -Jay
On Fri, May 25, 2012 at 2:29 PM, Prashanth Menon <prashanth.men...@gmail.com > wrote: > Yup, option 4 is much nicer and very much idiomatic Scala, aside from > allowing mutation. > > We should also reconsider how we're using Option's through our code as I'm > seeing things like "if(option.isDefined)" which should be avoided. > Checking for the condition of the option defeats the purpose of having > one. Instead, we should leverage the map and getOrElse funcitonality > that's awesome to work with :) > > - Prashanth > > On Fri, May 25, 2012 at 5:29 PM, Jay Kreps <jay.kr...@gmail.com> wrote: > > > Yes, that's my understanding. This blog gives a reasonable overview: > > http://www.dustinmartin.net/2009/10/getters-and-setters-in-scala/ > > > > Kind of sad that a year or so in we are just figuring this out, but I > guess > > better late then never. :-) > > > > -Jay > > > > On Fri, May 25, 2012 at 2:13 PM, Joel Koshy <jjkosh...@gmail.com> wrote: > > > > > Personally, I like options 3 and 4. (Option 4 more than 3, but I'm not > > sure > > > I follow it correctly - and I did not know that shorthand for > > overloading! > > > So is this right:) > > > > > > class GetSetXYZ { > > > private var underlying = 10 > > > def xyz = underlying > > > def xyz_=(x: Int) {underlying = x} > > > } > > > > > > val o = new GetSetXYZ > > > println(o.xyz) // 10 > > > o.xyz=5 > > > println(o.xyz) // 5 > > > > > > On Fri, May 25, 2012 at 10:17 AM, Jay Kreps <jay.kr...@gmail.com> > wrote: > > > > > > > Oh no, you are no using xyz_() you are overriding =. So you define > > > > xyz_=(x:Int) > > > > but to call it you do > > > > o.xyz = 5 > > > > The reason this is nice is because you can start with a simple > > > > var xyz > > > > and not need any getter/setter. Then later when you need to change > the > > > > behavior of the get you make > > > > def xyz = ... > > > > and none of the calling code changes. Later still you decide you need > > to > > > > override the setter you do > > > > def xyz_=(x: Int)... > > > > and that overrides o.xyz=5, again without changing the calling code. > > > > > > > > Basically the point is that scala generates these getters and setters > > no > > > > matter what so you might as well use the official scala mechanism. > > > > > > > > Since I am only semi-scala literate any of the above may be wrong. > > > > > > > > -Jay > > > > > > > > On Fri, May 25, 2012 at 9:42 AM, Jun Rao <jun...@gmail.com> wrote: > > > > > > > > > I think separating out the getter and setter makes the > implementation > > > > > cleaner. I am not sure how intuitive it is to use xyz_() as the > > setter, > > > > > although it is concise. > > > > > > > > > > Thanks, > > > > > > > > > > Jun > > > > > > > > > > On Tue, May 22, 2012 at 9:13 PM, Jay Kreps <jay.kr...@gmail.com> > > > wrote: > > > > > > > > > > > We are a little inconsistent in our use of setters and getters. I > > > think > > > > > for > > > > > > the most part well-written code shouldn't have too many setters > and > > > > > getters > > > > > > (especially setters) since they expose internal details of the > > > object. > > > > > But > > > > > > sometimes you need them. I see three common conventions: > > > > > > > > > > > > 1. Java-style getXyz() and/or setXyz() method > > > > > > 2. xyz() plus semantically named setter that describes what it > > > does. > > > > > > 3. In some newer code I see xyz(x: Option[Int]) > > > > > > > > > > > > There is also a forth option. My understanding of the proper > scala > > > > idiom > > > > > > was actually that scala automatically created get and set methods > > for > > > > > you, > > > > > > and the appropriate thing to do is to override these. This is > > > described > > > > > > here: > > > > > > http://www.codecommit.com/blog/scala/scala-for-java-refugees-part-2 > > > > > > > > > > > > Essentially you can start with just > > > > > > > > > > > > val xyz = ... > > > > > > > > > > > > Then later if you want to override the getter you would do > > > > > > > > > > > > private val x = ... > > > > > > > > > > > > // getter > > > > > > > > > > > > def xyz = if(check_something) x else throw new > > IllegalStateException > > > > > > > > > > > > Then if you also want to add a setter you do > > > > > > > > > > > > private val x = ... > > > > > > > > > > > > def xyz = if(check_something) x else throw new > > IllegalStateException > > > > > > def xyz_=(x: Int) {xyz = x} > > > > > > > > > > > > Let's pick one of these and refactor towards it as we see code > that > > > > > doesn't > > > > > > match. My vote would be for option 4. > > > > > > > > > > > > -Jay > > > > > > > > > > > > > > > > > > > > >
