Is the idea here to offer a wrapping API for such collections to Groovy application developers, or merely use immutable collections inside Groovy, without exposing them to application developers?
On Wed, Oct 14, 2015 at 10:55 AM, Jochen Theodorou <blackd...@gmx.org> wrote: > Hi all, > > I was thinking of adding persistent collections to Groovy for quite a while > now. but I am wondering what library we should depend on here and wanted to > ask what you people generally use. Like pcollections, Guava, functional > Java, maybe stuff from Clojure or Scala? > > Background: > > persistent collection are collections (may or may not implement the > Collection interface) which cannot be modified later on. they have nothing > to do with persisting data in a database or on hard disc. They are just more > functional structures. Even though you cannot modify them, you can combine > the structure with new elements and get a new structure. So a list+element > will create a new list consisting of the old list and the new element. But > they will not just copy over data, they will reuse the internal structure of > the old list. A very simple form is that of a filo stack. It can be a simple > linked list of elements and we add the new element in front, letting us to > reuse the old list to almost 100% and to create only a very small amount of > new objects. There are of course lists, sets and maps. > > So why use them? Unlike unmodifiable made collections in Java, these > persistent collections are relatively safe to share between threads with > minimal synchronizations. Also, if you are working with functional idioms > they are more fitting the implicit assumptions of the data not being > modifiable. > > Java collections are in general a bad fit here, since Collections are more > or less assumed to be modifiable. pcollections for example tries to bridge > that. In a Java8 world there is of course streams, which are a much better > fit in that. > > bye blackdrag
