[Haskell-i18n] Unicode in source

[Simon Marlow]

> I think it would be a good idea to *allow* the current rules, but
> *recommend* that blocks (of more than one line) are made up by lines
> indented with whitespace, and whitespace only.  Ideally, I'd like a
> compiler warning for this, but at least we should warn when
> multi-(or unknown-)column characters may affect indentation levels? 

erm... isn't that exactly what I suggested?

   - We recommend that programmers avoid using indentation levels
     which depend on the widths of non-space characters.

Ok, I'll re-word it to be a bit more precise:

   - We recommend that programmers avoid writing code whose syntactic
     interpretation depends on the widths of non-space characters.

which amounts to not writing code like:

    case x of True  -> e1
              False -> e2

or 
  
    case x of
      {- case 1 -} True  -> e1
      {- case 2 -} False -> e2

(note that simply requiring a newline before the first declaration
wouldn't outlaw the second case, you would also have to require that the
line begins with whitespace only).

Cheers,
	Simon