How can I check if an element is iterable?

[Marcone]

On Monday, 4 May 2020 at 01:49:28 UTC, Ali Çehreli wrote:
> On 5/3/20 1:44 PM, Marcone wrote:
>> [...]
>
> Still, the type of a variable would determine whether whether 
> it's iterable.
>
> As an improvement, the following program can be changed to call 
> use() recursively to visit all members of e.g. structs (which 
> can be determined by 'is (T == struct)').
>
> import std.stdio;
> import std.traits;
>
> void use(T)(T var, size_t indent = 0) {
>   static if (isIterable!T && !isSomeString!T) {
>     foreach (i, e; var) {
>       writefln!"%*s: %s"(indent, i, e);
>     }
>
>   } else {
>     writefln!"%*s"(indent, var);
>   }
> }
>
> void main() {
>   int i = 42;
>   string s = "hello";
>   double[] arr = [ 1.5, 2.5, 3.5 ];
>   use(i);
>   use(s);
>   use(arr);
> }
>
> Ali

Very good! Thank you!