Re: Bug#478019: zsh: Should handle non-breaking space as word separator

[Peter Stephenson <p.w.stephenson@ntlworld.com>]

On Sat, 26 Apr 2008 16:05:48 +0100
Clint Adams <schizo@debian.org> wrote:
> On Sat, Apr 26, 2008 at 12:00:03PM +0100, Samuel Thibault wrote:
> > On a french keyboard, '|' is typed by using alt-gr, and the non-breaking
> > space is often typed by using alt-gr space. That often leads to this:
> > 
> > € echo a | grep a
> > zsh: command not found:  grep
> > 
> > Because zsh looks for a " grep" command, with leading non-breaking space
> > because my thumb remained a bit too long on the alt-gr key.
> > 
> > This doesn't happen with bash, because bash treats non-breaking space as
> > a word separator.  Could zsh do the same? (currently, I have defined
> > alias  grep=grep
> > alias  vi=vi
> > ...)
> 
> Having locale-based (and multibyte) word separators sounds like a nightmare
> to me, but maybe someone has some ideas.

I tend to agree with this.  It's doable, and the standard (SUS 2004)
supports the idea (see under LC_CTYPE) although it's a little bit
two-faced (only ASCII space characters are listed as requiring quoting,
for example).  However,

- I've been resisting having to convert the byte stream into anything
  else for basic shell parsing.  I've got far better things to do
  than make the shell slower and buggier for a feature of doubtful
  general utility.
- Having basic syntactic elements depending on the locale is really
  nasty.  We have one such kludge ourselves, (NO_)POSIX_IDENTIFIERS,
  which is mostly a sop to traditional pre-multibyte zsh behaviour.  I
  would actively discourage people from assuming this sort of behaviour.
- It seems to me somewhat ludicrous making a change specifically so
  that arguments can be separated by a "non-breaking" space.  Is it
  or isn't it breakable?
- This isn't a general solution to mistyping anyway.  You might be able
  to fix alt-gr space with xmodmap or the terminal emulator translation
  table.

(Yes, I know "a little bit two-faced" is meaningless, strictly
speaking.  I stopped speaking strictly years ago now.)

-- 
Peter Stephenson <p.w.stephenson@ntlworld.com>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/