D graph library -- update

[Joseph Rushton Wakeling]

On Thursday, 11 July 2013 at 18:14:01 UTC, w0rp wrote:
> I don't like it. Here is why.
>
> 1. You can only use a size_t type as the vertex type. What 
> about strings?

This is a core graph type designed explicitly for speed and 
efficiency. If you want string ids for vertices, it's better to 
wrap this with maps from string to size_t and back again. Having 
strings or other arbitrary data types involved in the core data 
type will just be a nightmare space- and speed-wise.

> 2. The distinction between directed and undirected graphs is 
> made with an boolean type parameter? Why not an enum?

It is an enum.

> why not just use interfaces? (You are already using classes and 
> garbage collected memory.)

It's in consideration. I haven't yet identified a clear need.

> 3. I have to control the graph's capacity manually, and I can't 
> use arbitrary numbers for edges.
> 4. Adding an edge doesn't add vertices.

Again, those things are probably best achieved by wrappers that 
mediate the adding of edges.

> My most common use of graphs is to start from nothing, build 
> from adding edges arbitrarily, usually from IDs which may be 
> integers, and may be strings, and then use graph algorithms to 
> gain some understanding of the relation between objects mapped 
> to these IDs. With this library, this will be difficult or 
> impossible.

I understand those requirements, I just think that the core data 
structure on which calculations are done is not the ideal place 
to implement them.

(Sorry for terse replies, I'm writing on my phone...)