D语言字符

import std.stdio;
import std.uni;

void main() { 
   writeln(Is ğ lowercase? , isLower('ğ')); 
   writeln(Is Ş lowercase? , isLower('Ş'));  

   writeln(Is İ uppercase? , isUpper('İ')); 
   writeln(Is ç uppercase? , isUpper('ç')); 

   writeln(Is z alphanumeric? ,       isAlpha('z'));  
   writeln(Is new-line whitespace? ,  isWhite('\n')); 

   writeln(Is underline whitespace? , isWhite('_'));  

   writeln(The lowercase of Ğ: , toLower('Ğ')); 
   writeln(The lowercase of İ: , toLower('İ')); 

   writeln(The uppercase of ş: , toupper('ş')); 
   writeln(The uppercase of ı: , toupper('ı')); 
}