[Haskell-i18n] Unicode in source

Sven Moritz Hallberg pesco@gmx.de
26 Aug 2002 12:19:14 +0200

On Mon, 2002-08-26 at 11:33, Simon Marlow wrote:
> Allowing characters to span more than one column wouldn't break the
> layout rule, as long as the character to column mapping is generally
> agreed upon across editors and locales.  (I think we established that
> this is not necessarily the always case, although in practice it should
> be).

I guess we can just refer to the Unicode standard for the mapping?

> Requiring a newline before a new layout context would break *a lot* of
> code.   You can't write 'let x = 42 in x + 1' for example.  Sure, a
> refinement could be made to allow these kind of things, but this will
> serve to make the layout rule more complex, rather than less.  So to
> extend gracefully while keeping backwards compatibility, I propose:
>    - There be a fixed character->column mapping

I agree.

>    - Tab stops are every 8 columns

This appears to be the only viable solution if we don't want to force
layout blocks to start after newlines, your argument against which I

>    - We recommend that programmers avoid using indentation levels
>      which depend on the widths of non-space characters.
> Obeying the third requirement means that your code will look fine in a
> proportional font.  The compiler could warn about violations quite
> easily.  Note that it is ok to write 'let x = 42 in x + 1', because the
> meaning of the code doesn't depend on the actual indentation level of
> the first 'x'.

Good point, I'd be happy with it.

Sven Moritz