How can this best be done?

[Johan Fjeldtvedt]

This post concerns the following code:

https://gist.github.com/Jaffe-/6983847

It is an attempt to abstract away the details of storing a 
collection of struct elements as so-called parallel arrays 
(http://en.wikipedia.org/wiki/Parallel_array) instead of storing 
them sequentially.

The ParallelArray template takes a struct, S, and a number of 
elements, SIZE, and creates a struct where each field is an array 
of size SIZE, for each field of S. The struct overloads opIndex, 
opIndexAssign and opApply, so that it can be used just like an 
ordinary array of structs.

It's pretty neat and works fine, but I feel it's somewhat hacky. 
Is it okay to use .tupleof the way I do here? It does work, but I 
can't say I understand exactly how. Also, the recursive template 
bugs me. Can the code which declares the struct members be 
generated in some better way? I've tried writing a CTFE-able 
function to build the string instead of doing it recursively in 
the template, but I haven't been able to do it yet.