I'm looking for a way to obtain automatically the following layout of French "continuous guillemets", used in old typography when a citation includes another citation that spreads over several lines (ok, this might look strange at first sight):
« When Bill arrived at the door, he
saw him. The boy said: «Hello, I'm John
» and I'm 10 years old. I live
» with my parents in town. What
» do you want? » Bill was surprised
but answered the boy. »
I would like to do this automatically with XeLaTeX. The LaTeX code might look like this:
« When Bill arrived at the door, he saw him. The boy said: \continuousguil{Hello, I'm John and I'm 10 years old. I live with my parents in town. What do you want?} Bill was surprised but answered the boy. »
This is almost David's great answer in this post: Environment prints same character at beginning of each output line
But there are some differences, though, and I'm not able to adapt the code myself... Indeed, David's environment begins necessarily on a new line (whereas I want to begin in the middle of a line, possibly), and the same at the end: I'd like to be able to continue on the same line...
When I try to adapt the code, I am running into an error: "Improper \prevdepth".
Any idea on how to do this?
Thanks in advance!
Edit following David Carlisle's answer:
When trying your solution, I get something like this:
Two problems here: the first line of the nested citation is not justified, and there is some extra vertical space before the last line of the nested citation... This last problem does not always occur, though.
Just to be complete, I should mention that I replaced the "prefix" » in your code by \nospace{»}\hspace{.25em}, where the nospace command disables the automatic French spacing of the polyglossia package. Here is the complete code (I changed almost nothing to David's code; the \phantom{} at the beginning of the command is an ugly hack to have proper spacing after the guillemet):
\documentclass[12pt]{article} % Essai de guillemets continus
\usepackage{fontspec}
\defaultfontfeatures{Mapping=tex-text}
\setmainfont[Ligatures={TeX}, Numbers={OldStyle}]{Adobe Garamond Pro}
\usepackage{polyglossia}
\setdefaultlanguage{french}
\renewcommand\labelitemi{---}
\usepackage{microtype}
\setlength\textwidth{10cm}
% Enlever espace avant ponctuation
\makeatletter
\newcommand{\nospace}[1]{\nofrench@punctuation#1\french@punctuation}
\makeatother
% Commande guilcont
\makeatletter
%https://tex.stackexchange.com/questions/107726/how-to-get-the-natural-width-of-the-last-box-in-a-paragraph/107727#107727
\def\lastlinelength{%
{\abovedisplayshortskip\z@\abovedisplayskip\z@
\belowdisplayshortskip\z@\belowdisplayskip\z@
$$\global\dimen\@ne\dimexpr\predisplaysize-2em\relax
\xdef\tmp{%
\predisplaysize\the\predisplaysize
\prevgraf\the\prevgraf\relax}%
$$\vskip\dimexpr-\parskip-\baselineskip\relax}\tmp}
% The code for the start of environment
\def\guilcont#1{«\phantom{}%
\lastlinelength
% save the depth of the previous line (Normally
% TeX uses this automatically but would lose the
% informatiom due to the boxing/reboxing)
\dimen0\prevdepth
% Save the prefix text from `#1` in box 0.
% In this version make it red, probably real code
% should not do that and should just have `#1` you
% could always add colour or font changes in the argument.
\setbox0\hbox{\nospace{»}\hspace{.25em}}%
% start saving the paragraph in box 2
\setbox2\vbox\bgroup\bgroup\vskip94sp
% by resetting the prevdepth to the saved value
% Tex will automatically insert glue to maintain even spacing
% before the first line.
\prevdepth\dimen0
% Reduce the width for line breaking by the width of box 0 to allow for
% the insertion of the prefix string later.
\advance\hsize-\wd0
% end of begin environment code
\noindent\vadjust{\penalty123}\kern\dimen1 #1%
% close off the saving of box 2 started above.
\endgraf\egroup\egroup
% So at those point box 2 contains the body of the environment
% with lines broken to a short line length.
%
% Clear box 1 ready to start collecting the modified lines
\global\setbox1\vbox{}%
% Use unbox box2 (onto itself)
\setbox2\vbox{%
\unvbox2
\global\setbox5\lastbox
\unskip
% at this point we are at the end of box 2 now
% loop backwards up the vertical list copying glue and penalties
% but modifying boxes to add the prefix.
\loop
%
% an e-tex primitive that reports the last item in the vertical list.
% type 1 is a box, so remove the box (a line of text) and then
% put into box 1 a box that is this box together with the prefix which
% was saved in box 0
\ifnum\lastnodetype=1
\global\setbox3\lastbox
\global\setbox1\vbox{%
\hbox{\copy0\box3}%
\unvbox1}%
\fi
%
% type 11 is glue so remove it from this list and add
% equivalent glue to box 1
\ifnum\lastnodetype=11
\skip0\lastskip\unskip
\global\setbox1\vbox{\vskip\skip0\unvbox1}%
\fi
%
% same for penalty
\ifnum\lastnodetype=13
\count0\lastpenalty\unpenalty
\ifnum\count0=123
\setbox0\hbox{}%
\else
\global\setbox1\vbox{\penalty\count0 \unvbox1}%
\fi
\fi
%
% other node types are not handled here: either they won't happen
% or they can't be removed anyway so would break the loop \special
% for example would be bad.
%
% -1 means the vertical list is empty: we have reached the top of the box.
\ifnum\lastnodetype=-1
\else
\repeat}%
% Tip the modified box back onto the main list for the page, unbox
% it so that page breaking may still happen (if it could happen in the
% original context).
\vskip-\baselineskip
\unvbox1
\noindent\nospace{»}\hspace{.25em}\unhbox5\unskip\unskip\ »%
}
\begin{document}
«Il y a huit ans que je suis avec vous, n'est-ce pas? Eh bien, dès le premier
jour, je me suis dit : \guilcont{Dès que j'aurai amassé cinq mille francs, je
m'en retournerai là-bas; j'achèterai la maison à Lagache, et je vivrai bien
heureuse…} C'est une promesse que je me suis faite, vous comprenez.»
\end{document}
Any idea on how I could fix these two minor problems? Thanks!
polyglossiainstead ofbabel, do you know if the same exists with polyglossia? And btw, what is the difference between babel and polyglossia: which one should I use preferably?polyglossia, only tested it once, because it seems the options for the french language are scarce inpolyglossiacompared to whatbabel-frenchprovides.