> 5) foreach(c; s1) yields a code point dchars regardless if s1 is string, dstring, wstring. > But you can use foreach(char c; s1) if s1 is a string and you are sure s1 uses only 7 bit chars. But in such cases you can also use a immutable(ubyte)[]. Python3 does something similar, its has a str type that's always UTF16 (or UTF32) and a bytes type that is similar to a ubyte[]. I think D can do something similar. std.string functions can made to work on ubyte[] and immutable(ubyte)[] too.
Actually I think D should depreciate char and wchar in user code except inside externals for compatibility with C and Windows functions. When you are working with individual characters you almost always want either a dchar or a byte.
