Wrong spacing around guillemets

Question

I use UTF-8 encoding to type a document in French, with the following definitions for guillemets:

\DeclareUnicodeCharacter{AB}{\og}
\DeclareUnicodeCharacter{BB}{\fg\xspace}

and the Babel package:

\usepackage[francais]{babel}

However, when I type a text like ceci cela «~quoted~» ceci cela, the spacing is wrong around the opening guillemet:

Notice that the space before the opening guillemet is too small, and the spacing after is too large. The closing guillemet has correct spacing. How could I fix that?

Answer 1

The spacing is already inserted by \og and \fg, so you shouldn't type the ~. You can consider changing the definition of the Unicode character as

\DeclareUnicodeCharacter{AB}{\og\ignorespaces}
\DeclareUnicodeCharacter{BB}{\unskip\fg}

so that inputting

Ces simulations «directes» sont ainsi

Ces simulations « directes » sont ainsi

will be equivalent.

Notice that \xspace does nothing.

If you insist to type «~directes~», then the definition for the open guillemets character could be

\makeatletter
\DeclareUnicodeCharacter{AB}{%
  \og\@ifnextchar~{\@gobble}{}}
\makeatother

_{Say what you want, but I find this spacing awful. ;-)}