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

[Stephane Chazelas <Stephane_Chazelas@yahoo.fr>]

On Sat, Apr 26, 2008 at 04:05:48PM +0100, Clint Adams wrote:
> On Sat, Apr 26, 2008 at 12:00:03PM +0100, Samuel Thibault wrote:
> > Hello,
> > 
> > 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.

Having the shell syntax that depends on the environment looks
like a very bad idea to me (think of scripts!).

There are already problems like that such as

case $x in
  ([a-z]) ...;;
esac

which is locale dependent while in most cases it's not what you
want. And to work around that is a nightmare POSIXly like:

LC_ALL=C command eval 'case $x in ([a-z]) ... esac'
(which doesn't even work in some shells because of bugs).

Another bad example which is causing more harm than benefit:

in ksh93, the decimal point is locale dependent, so you can't
do:

float Pi=3.14159265359

which is a syntax error is some locales:
$ LC_ALL=fr_FR ksh93 -c 'float Pi=3.141592653589'
ksh93[1]: typeset: 3.141592653589: arithmetic syntax error

This one is even harder to overcome:

$ LC_ALL=fr_FR ksh93 -c '
  LC_ALL=C command float Pi=3.141592653589; print $Pi'

$ LC_ALL=fr_FR ksh93 -c 'LC_ALL=C command eval float Pi=3.141592653589
 print $((Pi))'
ksh93: line 2: 3.141592653589: arithmetic syntax error

LC_ALL=fr_FR ksh93 -c 'in_C_locale() { typeset LC_ALL=C; eval "$@"; }
in_C_locale float Pi=3.141592653589; echo $LC_ALL;  print $((Pi))'
C
3.141592653589

All of which look like bugs to me.

Anyway, my point was to say that it's a bad idea to have the
syntax of the shell dependant on the locale.

-- 
Stéphane