d - Templated Multi-Dimensional Arrays -

i'm trying experiment templates , tried implement templated arrays, can declared like:

array!(float, 3, 2, 1) myarray; 

i've browsed through several implementations of problem in c++ can't seem convert d have little experience language (with d).

anyways these stuff tried, unfortunately none of them worked:

1. compile-time functions - generate code of format

"datatype[d0][d1]...[dn] identifier"

import std.conv;  static string generatearray(d...)(string type, string identifier, d dimensions) {     string result = type;      for(int = 0; < dimensions.length; i++)     {         result ~= "[" ~ to!(string)(dimensions[i]) ~ "]";     }      result ~= " " ~ identifier ~ ";";      return result; }  int main(string[] args) {     enum deb = generatearray("float", "data", 3, 2, 1);     pragma(msg, deb);      return 0; } 

which can wrap simple array class

class array(t, d...) {     mixin(generatearray(t, "data", d)); } 

but code fails with:

./template_recursion.d(10): error: variable cannot read @ compile time ./template_recursion.d(18): error: template instance template_recursion.expandtuple!(int, int, int) error instantiating ./template_recursion.d(18): error: ctfe failed because of previous errors in expandtuple 

2. recursive templates - stated earlier have seen implementations of in c++, can't seem transform statements d compiler accepts.

variadic templates in c++

template<class t, unsigned ... restd> struct array;  template<class t, unsigned primaryd >    struct array<t, primaryd> {   typedef t type[primaryd];   type data;   t& operator[](unsigned i) { return data[i]; }  };  template<class t, unsigned primaryd, unsigned ... restd >     struct array<t, primaryd, restd...> {   typedef typename array<t, restd...>::type onedimensiondownarrayt;   typedef onedimensiondownarrayt type[primaryd];   type data;   onedimensiondownarrayt& operator[](unsigned i) { return data[i]; } }; 

first code, using mixins:

dimensions aliasseq (aka typetuple, misnomer because 1 contains integers), can indexed values known @ compile time, runtime loop doesn't supply.

you can, however, use compile-time foreach loop, such:

foreach(auto dimension; dimensions) {     result ~= "[" ~ to!(string)(dimensions[i]) ~ "]"; } 

second code, using templates:

template multiarray(basetype, dimentions...) {     static if(dimensions.length == 0)         alias multiarray = basetype;     else         alias multiarray = multiarray!(basetype[dimensions[0]], dimensions[1..$]; }