Is_iso_alpha function

Where did we get this function from? Whats magical about char-code 128, 159, 189, 190, and 191? Aren’t we assuming a certain character encoding with this function?

More of my research on this. It turns out that at least in Windows encoding:

  • 159 is a Y with two dots on top of it Ÿ
  • 189 is the one-half sign ½
  • 190 is the 3/4 sign ¾
  • 191 is the inverted question mark ¿.

My again I don’t know why these characters are treated separately? Why not
195×which stands for an A with a ~ on top of it.