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