Possible candidate for addition to the Option API?

[Ken McDonald]

Forgive me if there's already a method for doing this--I just looked through the list of Option methods and couldn't find anything, but might have missed it. I'm just wondering if others find the following usage pattern common enough to add a (very simple) method to Option.

Basically:

var o: Option[A]

def f: A => B

var b: B

I frequently do something like:

o match {

    case Some(a) => f(a)

    case _ => b

}

I'd really like to just be able to say "o.applyOrElse(f, b)"

Opinions?

Thanks,

Ken

[Alex Cruise]

On Fri, Sep 9, 2011 at 6:37 PM, Ken McDonald <ykke...@gmail.com> wrote:

I'd really like to just be able to say "o.applyOrElse(f, b)"

o.map(f).getOrElse(b) innit?

-0xe1a

[Kevin Wright]

o map f getOrElse b

[Tony Morris]

class Option[A] {
// All Option methods can be defined in terms of this one
// aka catamorphism
def fold[B](some: A => B, none: => B) =
map(some) getOrElse none
}

--
Tony Morris
http://tmorris.net/

[Tony Morris]

http://blog.tmorris.net/further-understanding-scalaoption/
http://blog.tmorris.net/even-further-understanding-scalaoption-part-2/

HTH

[Debasish Ghosh]

+1 for fold .. just like we have in Either ..

Also if someone can explain why Option extends Product despite itself being a Sum type ..

Thanks.

--
Debasish Ghosh
http://manning.com/ghosh

Twttr: @debasishg
Blog: http://debasishg.blogspot.com
Code: http://github.com/debasishg

[√iktor Ҡlang]

On Sat, Sep 10, 2011 at 1:50 PM, Debasish Ghosh <ghosh.d...@gmail.com> wrote:

+1 for fold .. just like we have in Either ..

+1!
 

--
Viktor Klang

Akka Tech Lead

Typesafe - Enterprise-Grade Scala from the Experts

Twitter: @viktorklang

[Ken McDonald]

Boy, talk about being obvious in retrospect. But, that's why I asked--it wasn't obvious in prespect :-) Many thanks.

Ken

[Tony Morris]

BTW, we have it on List too, only it is called foldRight.