Clarify isUpper and isLower use ASCII

[ianbollinger]

Clarify that Char.isUpper and Char.isLower only recognize ASCII letters.

[evancz]

What do you think of using this approach instead? Looks like we could capture unicode stuff as well, but honestly, I'm not 100% sure what that means in practice.

[evancz]

What do you think of using this approach instead? Looks like we could capture unicode stuff as well, but honestly, I'm not 100% sure what that means in practice.

[jvoigtlaender]

I'm going to merge the documentation change here. It is a fact that the current implementations of isUpper and isLower work only for ASCII characters. Making them work for unicode characters would be a separate issue. Right now, the documentation should state the correct thing, which this PR achieves.

[jvoigtlaender]

I'm going to merge the documentation change here. It is a fact that the current implementations of isUpper and isLower work only for ASCII characters. Making them work for unicode characters would be a separate issue. Right now, the documentation should state the correct thing, which this PR achieves.

[rofrol]

@evancz I like this approach better http://stackoverflow.com/questions/1027224/how-can-i-test-if-a-letter-in-a-string-is-uppercase-or-lowercase-using-javascrip/9728437#9728437

And here is a quick workaround in elm:

isUpper: Char -> Bool
isUpper c =
  let
    s = String.fromChar c
  in
    s == String.toUpper s && s /= String.toLower s

isLower: Char -> Bool
isLower c =
  let
    s = String.fromChar c
  in
    s /= String.toUpper s && s == String.toLower s

[rofrol]

@evancz I like this approach better http://stackoverflow.com/questions/1027224/how-can-i-test-if-a-letter-in-a-string-is-uppercase-or-lowercase-using-javascrip/9728437#9728437

And here is a quick workaround in elm:

isUpper: Char -> Bool
isUpper c =
  let
    s = String.fromChar c
  in
    s == String.toUpper s && s /= String.toLower s

isLower: Char -> Bool
isLower c =
  let
    s = String.fromChar c
  in
    s /= String.toUpper s && s == String.toLower s