Nim and OO, Part II

Fri, 31 Oct 2014 00:00:00 +0000

In the previous article when I explored OO mechanisms in Nim I felt I dropped the ball a bit in my Fruit example. This is a followup.

In that article we first implemented some Fruit “classes” mixing methods and procs. Then I presented a cleaned up version using methods only, and a teeny template in order to reuse a base method. This template was needed since Nim currently doesn’t have a “call-next-method-matching” for multimethods like Dylan or CLOS have. This is being discussed and I think all agree that there needs to be some mechanism so that you can call a “next lesser match” of all matching multimethods.

But I also wrote that the example can be written perfectly well using generics and procs only, thus ensuring static binding and maximum speed. But the “super call” problem also existed for procs, and the template hack was just a hack. After more experimentation I now think I found the proper Nim way to do this so let’s take a look…

Nim and OO, Part III

Fri, 31 Oct 2014 00:00:00 +0000

So previously in Nim and OO Part II we saw how we could solve the “super call” issue using only procs and generics in Nim . This means that all code is statically bound.

But if you have read all these article you know I also tried the more appropriate mechanism for OO - so called methods. In Nim a proc is a regular statically bound function, simple and fast. A method on the other hand uses dynamic multimethod dispatch on the runtime types of all object parameters. The easy way to do objects in Nim (with inheritance of behavior) is using methods - but of course, this means dynamic lookup that has a runtime cost, but quite small as we will see.

Time for benchmarking!

Generics on Roads Less Taken

Nim and OO, Part II

Nim and OO, Part III