Obsecure problem 1

[Salih Dincer]

On Sunday, 31 July 2022 at 14:52:03 UTC, FeepingCreature wrote:
> Note sure if I'm misunderstanding, but: D does not copy strings 
> on value passing, because they're inherently reference types.
>
> You can think of a string (or any array) as a `struct { size_t 
> length; T* ptr; }` combined with a bunch of syntax magic.

You got it right, but I didn't explain it right. I think you are 
right. How could I forget! String is actually a struct, embedded 
in the language. For example, it has members like .dub, .ptr, 
capacity and .length (get/set).

Of course we should get a copy with .dub to avoid side effects.  
But now that I've tested it, I haven't seen a problem with 
split() and sort() .  Okay, yes sort() can have side effects, for 
example nums is affected by this.  I also had to use to!(dchar[]) 
because of the UTF:

```d
auto sortStr(string E)(string str) {
   import std.algorithm, std.conv;
   return str.to!(dchar[]).sort!E;
}

auto splitStr(string E)(string str) {
   import std.string;
   return str.split!string(E);
}

auto sortArray(T)(T[] arr)
{
   import std.algorithm;
   return arr.sort;
}

void main()
{
   import std.stdio : writeln;

   string test = "alphabet";
   auto nums = [ 1, 9, 4, 0, 3 ];

   test.sortStr!"a > b".writeln;
   assert(test == "alphabet");

   test.splitStr!"a".writeln;
   assert(test == "alphabet");

   test.sortStr!"a < b".writeln;
   assert(test == "alphabet");

   nums.sortArray.writeln;
   assert(nums == [0, 1, 3, 4, 9]);
}
/* Prints:
tplhebaa
["", "lph", "bet"]
aabehlpt
[0, 1, 3, 4, 9]
*/
```
In conclusion, one has to be careful, but D is a reliable 
language.

SDB at 79