toggleCase() for Narrow String

[Paul Backus]

On Sunday, 13 April 2025 at 17:28:12 UTC, Salih Dincer wrote:
> Hi,
>
> Please watch: https://youtu.be/siw602gzPaU
>
> If he had learned this method like me, he would not have needed 
> if's and long explanations. :)
>
> It's a very redundant thing (ASCII magic) that also weeds out 
> the incompatible character set. This approach adopts the 
> toggle/flip method through XOR rather than toLower/toUpper:

This is clever, but you are still missing something important. 
Take a look at this example:

     string test = "I love dlang!";
     test.toggleCase().writeln(); // "iLOVEDLANG" - wrong!