please help me to reverse a function call order

[Salih Dincer]

On Sunday, 24 July 2022 at 08:16:41 UTC, Test123 wrote:
> On Saturday, 23 July 2022 at 23:14:03 UTC, Salih Dincer wrote:
>> On Saturday, 23 July 2022 at 22:50:55 UTC, Salih Dincer wrote:
>>> [...]
>>
>> I guess my code didn't list all possibilities either. 
>> Moreover, the m and n parameters will be swapped:
>>
>>> [...]
>>
>> **PS.** * marked from version(c) in the above list is from 
>> version(b).
>>
>> SDB at 79
>
> Can you share your code ?
>
>
> The restuls is position unrelated.

Everyone has it, the classic permutation codes.There should even 
be something in the standard library?

I didn't share because I didn't know what you looking for. But 
you know this classic recurisive function:

```d

void permut(T)(T[] x, ref int count, int start = 0) {
   auto len = cast(int)x.length;
   if(start != len)
   {
     for(int i = start; i < len; i++)
     {
       x[start].swap(x[i]);
       x.permut(count, start + 1);
       x[start].swap(x[i]);
     }
   } else if(len < 9) x.writeln(": ", ++count);
   else ++count;   // ^---a lot of output
}

void swap(T)(ref T x, ref T y) {
   auto t = y;
        y = x;
        x = t;
}

T factorial(T)(in T n) pure nothrow @nogc
in(n < 21, "The number is a very large for ulongMax") {
   return n > 1 ? n * factorial(n - 1) : 1;
} unittest { assert (factorial!int(12) == 479001600); }


import std.range, std.stdio;

void main() {
   int totalCount, n = 3;

   iota(1, n + 1).array.permut(totalCount);
   totalCount.writeln(" permutation found...");

   assert(totalCount == n.factorial);
}
```

**PS.** I added extra factorial `assert()`...

SDB at 79