Automatic Follower

[Nick Sabalausky]

On Sat, 18 May 2013 16:35:29 +0200
"bearophile" <bearophileHUGS at lycos.com> wrote:

> Some of you maybe remember the idea of the roles of variables:
> 
> http://en.wikibooks.org/wiki/A-level_Computing/AQA/Problem_Solving,_Programming,_Data_Representation_and_Practical_Exercise/Fundamentals_of_Programming/The_Role_of_Variables
> 
> http://www.cs.joensuu.fi/~saja/var_roles/role_list.html
> 
> The idea is that in a program many variables have roles that can 
> be classified in few categories. Modern languages often offer 
> ways to express explicitly some of such roles, this makes the 
> code more readable and sometimes less bug prone.
> 
> One of the roles that isn't built-in in D is the Follower, that 
> is variables that get their value by following another data 
> entity. They are "used to keep check of a previous value of a 
> variable, so that a new value can be compared."
> 
> This is a basic implementation of a Follower in D (based on 
> std.typecons.Nullable), with an usage example on doubly linked 
> lists:
> 
> 
> struct WithFollower(T, size_t N) {


That's an interesting idea, I like it.