Templates and Associative Arrays - boring version

[downs]

dsimcha wrote:
> Wow, that is an impressive hack.  While it's certainly better than nothing, this
> is one area where it would be nice if the template system in D improved to make
> this cleaner and more obvious.  I am trying to learn/use D to replace scripting
> languages for programs involving huge CSV files, because the scripting languages
> are painfully slow for this.  I have a small custom library in PHP (which I use
> for general-purpose, not just web, scripting) for handling CSVs, and am trying to
> port it to D, and creating simple, clean templates for processing arrays without
> knowing at compile time whether they are regular or associative is a major hangup.

Alright, so here's the boring version :)

> 
> import std.stdio;
> 
> template Init(T) { T Init; }
> 
> template ElemType(T) {
>   static if (is(typeof(Init!(T).keys)))
>     alias typeof(Init!(T)[Init!(T).keys[0]]) ElemType;
>   else
>     alias typeof(Init!(T)[0]) ElemType;
> }
> 
> void main() {
>   writefln(ElemType!(ElemType!(int[][])).stringof);
>   writefln(ElemType!(ElemType!(float[string][string])).stringof);
>   writefln(ElemType!(ElemType!(real[float][])).stringof);
> }

 --downs