Commit: b042492ba42d5532181dcd00bb3f84961bd16e6c - luatexja (git)

ソースコードの管理場所

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• Revisão: b042492ba42d5532181dcd00bb3f84961bd16e6c (tree)
• Hora: 2011-11-22 20:05:25
• Autor: Hironori Kitagawa <h_kitagawa2001@yaho...>
• Commiter: Hironori Kitagawa

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Changed the reference for ptexenc.

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• modified: doc/ajt-devel-ltja.tex

Diff

--- a/doc/ajt-devel-ltja.tex
+++ b/doc/ajt-devel-ltja.tex
@@ -1,1235 +1,1235 @@
-%#!lualatex ajt-devel-ltja
-\documentclass{ajt}
-
-%%% Packages used in this paper
-
-%%% Font setting for \LuaTeX; this is extract from ajt.cls
-\makeatletter
-  \if@print
-    \RequirePackage{fontspec,xunicode}
-    \RequirePackage{luatextra}
-    \setmainfont[Mapping=tex-text]{Palatino LT Std}
-    \setsansfont[Mapping=tex-text]{Optima LT Std}
-  \else
-    \RequirePackage{fontspec,luatextra}
-    \setmainfont[Mapping=tex-text]{TeX Gyre Pagella} % \simeq Palatino
-  \fi
-
-%%% LuaTeX-ja
-\usepackage{luatexja,luatexja-fontspec}
-\ltjsetparameter{jacharrange={-3,-8}}
-\DeclareFontShape{JY3}{mc}{m}{n}{<-> s*[0.92489] file:ipam.ttf:jfm=ujis}{}
-\DeclareFontShape{JY3}{gt}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=ujis}{}
-% quick hack: monospaced Japanese font by \ttfamily
-\DeclareKanjiFamily{JY3}{\ttdefault}{}{}
-\DeclareFontShape{JY3}{\ttdefault}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=mono}{}
-
-
-%%% LTXexample environment
-\usepackage{showexpl,lltjlisting}
-\lstset{basicstyle=\ttfamily\small, width=0.3\textwidth,  basewidth=.5em}
-
-%%% Verbatim environment
-\usepackage{fancyvrb}
-\CustomVerbatimEnvironment{code}{Verbatim}%
-{numbers=left,xleftmargin=1.5em,baselinestretch=1.069,fontsize=\small}
-\CustomVerbatimEnvironment{codewithoutnum}{Verbatim}%
-{xleftmargin=1.5em,baselinestretch=1.069,fontsize=\small}
-\CustomVerbatimEnvironment{codewithoutnumsmall}{Verbatim}%
-{xleftmargin=1.5em,baselinestretch=1.0,fontsize=\footnotesize}
-\DefineShortVerb{\|}
-
-%%% Others
-\usepackage{mflogo,booktabs}
-\definecolor{grayx}{gray}{0.85}
-\hyphenation{
-  kanjiskip
-  xkanjiskip
-}
-
-%%% Mandatory article metadata %%%
-\title{Development of \LuaTeX-ja package}
-\author[北川 弘典]{Hironori Kitagawa}
-\address{\LuaTeX-ja project team}
-\email{h\[e-mail]}
-
-\keywords{\TeX, p\TeX, \LuaTeX, \LuaTeX-ja, Japanese}
-\abstract{%
-\LuaTeX-ja package is a macro package for typesetting Japanese
-documents under \LuaTeX.  The package has more flexibility of
-typesetting than \pTeX, which is widely used Japanese extension of \TeX,
-and has corrected some unwanted features of \pTeX.
-In this paper, we describe specifications, the current status and some
-internal processing methods of \LuaTeX-ja.
-}
-
-\newcommand{\parname}[1]{\textsf{#1}}
-\newcommand{\jstrut}{\vrule width0pt height\cht depth\cdp}
-\newcommand{\imagfm}[1]{\ifvmode\leavevmode\fi%
-  \hbox{\fboxsep=0pt\fbox{\setbox0=\hbox{#1}\copy0\kern-\wd0
-  \smash{\vrule width \wd0 height 0.4pt depth0.4pt}}}}
-\begin{document}
-
-%%% Do not forget to start with \maketitle!
-\maketitle
-
-\section{Introduction}
-\subsection{History}
-To typeset Japanese documents with \TeX, ASCII \pTeX~\cite{ptex} has
-been widely used in Japan.  There are other methods---for example, using
-Omega and OTP~\cite{omega}, or with the CJK package---to do so, however,
-these alternative methods did not become majority.  The author thinks
-that this is because \pTeX\ enables us to produce high-quality documents
-(e.g.,~supporting vertical typesetting), and the appearance of \pTeX\ is
-earlier than that of alternatives described above.
-
-However, \pTeX\ has been left behind from the extensions of \TeX\ such
-as \eTeX\ and \pdfTeX, and the diffusion of UTF-8 encoding.  In recent
-years, the situation has become better, by development of
-|ptexenc|~\cite{ptexenc} by Nobuyuki Tsuchimura (\hbox{土村展之}),
-$\varepsilon$-\pTeX~\cite{eptex} by the author,~and u\pTeX~\cite{uptex}
-by Takuji Tanaka (田中琢爾). However, continuing this approach, namely,
-to develop an engine extension localized for Japanese, is not wise. This
-approach needs lots of work for \emph{each} engine. In addition, if we
-use \LuaTeX, the necessity of an engine extension is getting smaller
-because \LuaTeX\ has an ability to hook \TeX's internal process by using
-Lua callbacks.
-
-
-There were several experimental attempts to typeset
-Japanese documents with \LuaTeX\ before. Here we cite three examples:
-\begin{itemize}
-\item |luaums.sty|~\cite{luaums} developed by the author. This
-      experimental package is for creating a certain Japanese-based presentation
-      with \LuaTeX.
-\item the \emph{luajalayout} package~\cite{luajalayout}, formerly known as the
-      \emph{jafontspec} package, by Kazuki Maeda (前田一貴). This package is based on
-      \LaTeXe\ and \emph{fontspec} package.
-\item the \emph{luajp-test} package~\cite{luajp-test}, a test package made by
-      Atsuhito Kohda (香田温人), based on articles on the web page~\cite{joylua}.
-\end{itemize}
-However, these packages are based on \LaTeXe, and do not have much
-ability to control the typesetting rule. And it is inefficient that more
-than one people separately develop similar packages.  Development of the
-\LuaTeX-ja package is started initially by the author and Kazuki Maeda, because of
-these situations.
-
-\subsection{Development policy of \LuaTeX-ja}
-\label{ssec-pol} 
-The first aim of \LuaTeX-ja project was to implement features (from the
-`primitive' level) of \pTeX\ as macros under \LuaTeX, therefore \LuaTeX-ja is
-much affected by \pTeX.  However, as development proceeded, some
-technical/conceptual difficulties arose. Hence we changed the aim
-of the project as follows:
-\begin{itemize}
-\item\emph{\LuaTeX-ja offers at least the same flexibility of
-     typesetting that p\TeX\ has.}
-
-     We are not satisfied with the ability of producing outputs conformed to
-     JIS~X~4051~\cite{jisx4051}, the Japanese Industrial Standard for
-     typesetting, or to a technical note~\cite{w3c} by W3C;
-     if one wants to produce very incoherent outputs for some reason, it
-     should be possible.
-In this point, previous attempts of Japanese typesetting with \LuaTeX\
-     which we cited in the previous subsection are inadequate.
-
-\pTeX\ has some flexibility of typesetting, by changing internal
-     parameters such as |\kanjiskip| or |\prebreakpenalty|, and by using
-     custom JFM (Japanese TFM). Therefore we decided to include these
-     functionality to \LuaTeX-ja.
-
-\item\emph{\LuaTeX-ja isn't mere re-implementation or porting of \pTeX;
-     some (technically and/or conceptually) inconvenient features of
-     \pTeX\ are modified.} 
-
-     We describe this point in more detail at the next section.
-\end{itemize}
-
-
-\subsection{Overview of the processes}
-\label{ssec-over}
-We describe an outline of \LuaTeX-ja's process in order.
-
-\begin{itemize}
-\item In the |process_input_buffer| callback: treatment of breaking
-      lines after a Japanese character (in Subsection~\ref{ssec-line}).
-
-\item In the |hyphenate| callback: font replacement.
-
-\LuaTeX-ja looks into for each \textit{glyph\_node}~$p$ in the horizontal list. If
-	   the character represented by $p$ is considered as a Japanese
-	   character, the font used at $p$ is replaced by the value of
-	   |\ltj@curjfnt|, an attribute for `the current Japanese font'
-	   at~$p$.
-
-Furthermore, the subtype of $p$ is subtracted by 1 to suppress
-	   hyphenation around $p$ by \LuaTeX, because later processes of
-	   \LuaTeX-ja take care of all things about Japanese characters.
-
-\item In |pre_linebreak_filter| and |hpack_filter| callbacks:
-
-\begin{enumerate}
-\item \LuaTeX-ja has its own stack system, and the current horizontal
-      list is traversed in this stage to determine what the level of
-      \LuaTeX-ja's internal stack at the end of the list is. We will
-      discuss it in Subsection~\ref{ssec-stack}.
-
-\item In this stage, \LuaTeX-ja inserts glues/kerns for Japanese
-      typesetting in the list. This is the core routine of \LuaTeX-ja.
-      We will discuss it in Subsections
-      \ref{ssec-jglue}~and~\ref{ssec-jspec} .
-
-\item To make a match between a metric and a real font, sometimes
-      adjustument of the position of (Japanese) glyphs are performed.
-      We will discuss it in Subsection~\ref{ssec-width}.
-\end{enumerate}
-\item In the |mlist_to_hlist| callback: treatment of Japanese characters
-      in math formulas. This stage is similar to adjustment of the
-      position of glyphs (see above), so we omit to describe this stage
-      from this paper.
-\end{itemize}
-
-In this paper, a \emph{alphabetic character} means a non-Japanese
-character. Similarly, we use the word an \emph{alphabetic font} as the
-counterpart of a jJpanese font.
-
-\subsection{Contents of this paper}
-Here we describe the contents of the rest of this paper briefly.  In
-Section~\ref{sec:differences_with_ptex}, we describe major differences
-between \pTeX\ and \LuaTeX-ja.  The next section,
-Section~\ref{sec:distinction_of_characters}, is concentrated on a
-problem how we distinguish between Japanese characters and alphabetic
-characters. In Section~\ref{sec:current_status}, we show current
-development status of the package.  Finally, in
-Section~\ref{sec:implementation}, we describe some internal routines of
-\LuaTeX-ja.
-
-\subsection{General information of the project}
-This \LuaTeX-ja project is hosted by SourceForge.jp. The official wiki
-is located on
-\url{http://sourceforge.jp/projects/luatex-ja/wiki/}.  There is
-no stable version on October 22, 2011, however a set of developer sources can be
-obtained from the git repository.  Members of the project team are as follows
-(in random order): Hironori Kitagawa, Kazuki Maeda, Takayuki Yato,
-Yusuke Kuroki, Noriyuki Abe, Munehiro Yamamoto, Tomoaki Honda,
-and~Shuzaburo Saito.
-
-
-\section{Major differences with \pTeX}
-\label{sec:differences_with_ptex}
-In this section, we explain several major differences between \pTeX\
-and our \LuaTeX-ja.  For general information of Japanese typesetting and the
-overview of \pTeX, please see Okumura~\cite{ptexjp}.
-
-
-\subsection{Names of control sequences}
-\label{ssec-csname} Because \pTeX\ is an engine modification of Knuth's
-original \TeX82 engine, some of the additional primitives take a form that is
-very difficult to be simulated by a macro.  For example, an additional
-primitive |\prebreakpenalty|$\langle\hbox{\it
-char\_code}\rangle$|[=]|$\langle\hbox{\it penalty}\rangle$ in \pTeX\
-sets the amount of penalty inserted before a character whose code is
-$\langle\hbox{\it char\_code}\rangle$ to $\langle\hbox{\it
-penalty}\rangle$, and this form |\prebreakpenalty|$\langle\hbox{\it
-char\_code}\rangle$ can be also used for retrieving the value.
-
-Moreover, there are some internal parameters of \pTeX\ which values of them at the end of a
-horizontal box or that of a paragraph are valid in whole box or
-paragraph.  However, the implementation of these parameters in
-\LuaTeX-ja is not so easy; we will discuss it in Subsection~\ref{ssec-stack}.
-
-From above two problems  discussed above, the assignment and retrieval
-of most parameters in \LuaTeX-ja are summarized into the following
-three control sequences:
-\begin{itemize}
-\item |\ltjsetparameter{|$\langle\hbox{\it
-      name}\rangle$|=|$\langle\hbox{\it value}\rangle$|,...}|: for local
-      assignment.
-\item |\ltjglobalsetparameter|: for global assignment. Note that these two control
-      sequences obey the value of |\globaldefs| primitive.
-\item |\ltjgetparameter{|$\langle\hbox{\it
-      name}\rangle$|}[{|$\langle\hbox{\it optional
-      argument}\rangle$|}]|: for retrieval. The returned value is always
-      a string.
-\end{itemize}
-
-\subsection{Line-break after a Japanese character}
-\label{ssec-line} 
-
-Japanese texts can break lines almost everywhere, in contrast with
-alphabetic texts can break lines only between words (or use
-hyphenation). Hence, \pTeX's input processor is modified so that a
-line-break after a Japanese character doesn't emit a space. However,
-there is no way to customize the input processor of \LuaTeX, other than
-to hack its CWEB-source. All a macro package can do is to modify an input line before
-when \LuaTeX\ begin to process it, inside the |process_input_buffer|
-callback.
-
-Hence, in \LuaTeX-ja, a comment letter (we reserve U+FFFFF for this
-purpose) will be appended to an input line, if this line ends with a Japanese
-character.\footnote{Strictly speaking, it also requires that the catcode
-of the end-line character is 5~(\emph{end-of-line}). This condition is
-useful under the verbatim environment.}  One might jump to a conclusion
-that the treatment of a line-break by \pTeX\ and that of \LuaTeX-ja are
-totally same, however they are different in the respect that \LuaTeX-ja's
-judgement whether a comment letter will be appended the line is done
-\emph{before} the line is actually processed by \LuaTeX.
-
-Figure~\ref{fig-linebreak} shows an example of this situation; the
-command at the first line marks most of Japanese characters as
-`non-Japanese characters'. In other words, from that command onward, the
-letter `あ' will be treated as an alphabetic character by
-\LuaTeX-ja. Then, it is natural to have a space between `あ' and `y' in
-the output, where the actual output in the figure does not so.  This is
-because `あ' is considered a Japanese character by \LuaTeX-ja,
-when \LuaTeX-ja does the decision whether U+FFFFF will be added to the
-input line~2.
-
-\begin{figure}
-\begin{LTXexample}
-\font\x=IPAMincho \x
-\ltjsetparameter{jacharrange={-6}}xあ
-y
-\end{LTXexample}
-\caption{A notable sample showing the treatment of a line-break after a
-Japanese character.}\label{fig-linebreak}
-\end{figure}
-
-\subsection{Separation between `real' fonts and metrics}
-\label{ssec-sepmet}
-
-Traditionally, most Japanese fonts used in typesetting are not
-proportional, that is, most glyphs have same size (in most cases,
-square-shaped). Hence, it is not rare that the contents of different
-JFMs are essentially same, and only differ in their names. For example,
-|min10.tfm| and |goth10.tfm|, which are JFMs shipped with \pTeX\ for
-seriffed \emph{mincho} family and sans-seriffed \emph{gothic} family,
-differ their |FAMILY| and |FACE| only. Moreover, |jis.tfm| and
-|jisg.tfm|, which is included in the \emph{jis} font metric, which is
-used in \emph{jsclasses}~\cite{jsclasses} by Haruhiko Okumura (奥村晴彦),
-are totally same as binary files.  Considering this situation, we
-decided to separate `real' fonts and metrics used for them in
-\LuaTeX-ja. Typical declarations of Japanese fonts in the style of plain
-\TeX\ are shown in Figure~\ref{fig-jfdef}. We would like to add several
-remarks:
-\begin{itemize}
-\item A control sequence |\jfont| must be used for Japanese fonts, instead of |\font|.
-\item \LuaTeX-ja automatically loads the \emph{luaotfload} package, so
-      \hbox{\tt file:} and \hbox{\tt name:} prefixes, and various font features can be
-      used as the first line in Figure~\ref{fig-jfdef}.
-\item The |jfm| key specifies the metric for the font. In
-      Figure~\ref{fig-jfdef}, both fonts will use a metric stored in a
-      Lua script named |jfm-ujis.lua|. This metric is the standard
-      metric in \LuaTeX-ja, and is based on JFMs used in the \emph{otf}
-      package~\cite{otf}.
-\item The \hbox{psft:} prefix can be used to specify name-only, non-embedded
-      fonts. When one displays a pdf with these fonts, actual fonts which
-      will be used for them depend on a pdf reader. 
-\end{itemize}
-The specification of a metric for \LuaTeX-ja is similar to that of a JFM
-(see \cite{ptexjp}); characters are grouped into several classes, the
-size information of characters are specified for each class, and
-glue/kern insertions are specified for each pair of classes. Although
-the author have not tried, it may be possible to develop a program that
-`converts' a JFM to a metric for \LuaTeX-ja.  \LuaTeX-ja offers three
-metrics by default; |jfm-ujis.lua|, |jfm-jis.lua| based on the
-\emph{jis} font metric, and |jfm-min.lua| based on old |min10.tfm|.
-
- Note that |-kern| in features
-is important, because kerning information from a real font itself will
-clash with glue/kern information from the metric.
-
-\begin{figure}
-\begin{verbatim}
-\jfont\foo=file:ipam.ttf:jfm=ujis;script=latn;-kern;+jp04 at 12pt
-\jfont\bar=psft:Ryumin-Light:jfm=ujis at 10pt
-\end{verbatim}
-\caption{Typical declarations of Japanese fonts.}
-\label{fig-jfdef}
-\end{figure}
-
-\subsection{Insertion of glues/kerns for Japanese typesetting: timing}
-\label{ssec-jglue}
-
-As described in \cite{luatexref}, \LuaTeX's kerning and ligaturing
-processes are totally different from those of \TeX82.  \TeX82's process is
-done just when a (sequence of) character is appended to the current
-list. Thus we can interrupt this process by writing as
-|f{}irm|. However, \LuaTeX's process is \emph{node-based}, that is, the
-process will be done when a horizontal box or a paragraph is ended, so
-|f{}irm| and |firm| yield  same outputs under \LuaTeX.
-
-The situation for Japanese characters is more complicated.
-Glues (and kerns) which are needed for Japanese
-typesetting are divided into the following three categories:
-\begin{itemize}
-\item Glue (or kern) from the metric of Japanese fonts (\emph{JFM glue},
-      for short). 
-
-\item Default glue between a Japanese character and an alphabetic
-      character (\emph{xkanjiskip}, for short), usually 1/4 of
-      full-width (\emph{shibuaki}) with some stretch and shrink for
-      justifying each line.
-\item Default glue between two consecutive Japanese characters
-      (\emph{kanjiskip}, for short). The main reason of this glue is to
-      enable breaking lines almost everywhere in Japanese texts. In most
-      cases, its natural width is zero, and some stretch/shrink for
-      justifying each line.
-\end{itemize}
-In \pTeX, these three kinds of glues are treated differently. A JFM glue
-is inserted when a (sequence of) Japanese character is appended to the
-current list, same as the case of alphabetic characters in \TeX82. This
-means that one can interrupt the insertion process by saying |{}|.  A
-\emph{xkanjiskip} is inserted just before `hpack' or line-breaking of a
-paragraph; this timing is somewhat similar to that of \LuaTeX's kerning
-process. Finally, A \emph{kanjiskip} is not appeared as a node anywhere;
-only appears implicitly in calculation of the width of a horizontal box,
-that of breaking lines, and the actual output process to a DVI
-file. These specifications have made \pTeX's behavior very hard to
-understand.
-
-\LuaTeX-ja inserts glues in all three categories simultaneously inside
-|hpack_filter| and |pre_linebreak_filter| callbacks.  The reasons of
-this specification are to behave like alphabetic characters in \LuaTeX\
-(as described in the first paragraph in this subsection), and to clarify
-the specification for \LuaTeX-ja's process.
-
-\subsection{Insertion of glues/kerns for Japanese typesetting: specification}
-\label{ssec-jspec}
-
-\begin{table}
-\caption{Examples of differences between \pTeX\ and \LuaTeX-ja.}
-\label{tab-jfmglue}
-\begin{center}
-\begin{tabular}{llllllll}
-\toprule
-&\multicolumn{1}{c}{(1)}&\multicolumn{1}{c}{(2)}&\multicolumn{1}{c}{(3)}&\multicolumn{1}{c}{(4)}\\
-Input      &|あ】{}【〕\/〔|        &|い』\/a| &|う）\hbox{}（| &|え］\special{}［|\\\midrule
-\pTeX      &あ】\hbox{}【〕\hbox{}〔&い』\/a   &う）\hbox{}（   &え］\hbox{}［\\
-\LuaTeX-ja &あ】{}【〕\/〔          &い』\/a   &う）\hbox{}（   &え］\special{}［\\
-\bottomrule
-\end{tabular}
-\end{center}
-\end{table}
-
-\begin{figure}
-\begin{center}
-\fontsize{40}{40}\selectfont
-\imagfm{\jstrut あ}%
-\imagfm{\jstrut 】\inhibitglue}%
-\imagfm{\jstrut\kern.5\zw}%
-\imagfm{\jstrut\kern.5\zw}%
-\imagfm{\jstrut\inhibitglue【}%
-\imagfm{\jstrut 〕\inhibitglue}%
-\imagfm{\jstrut\kern.5\zw}%
-\imagfm{\jstrut\kern.5\zw}%
-\imagfm{\jstrut\inhibitglue〔}%
-\end{center}
-\caption{Detail of the output of \pTeX\ in the input~(1) in Table~\ref{tab-jfmglue}.}
-\label{fig-ptexjfm}
-\end{figure}
-
-Now we will take a look at the insertion process itself through four points.
-
-\begin{description}
-\item[Ignored nodes]
-As noted in the previous subsection, the insertion process in \pTeX\ can
-	   be interrupted by saying |{}| or anything else.\footnote{This
-	   is why some tricks like \texttt{ちょ\char`\{\char`\}っと} for
-	   \texttt{min10.tfm} and other `old' JFMs work.} This leads the
-	   second row in Table~\ref{tab-jfmglue}, or
-	   Figure~\ref{fig-ptexjfm}. Here `the process is interrupted'
-	   means that \pTeX\ does not think the letter `】\inhibitglue'
-	   is followed by `\inhibitglue【', hence two half-width glues
-	   are inserted between `】\inhibitglue' and `\inhibitglue【',
-	   where the left one is from `】\inhibitglue' and the right one
-	   is from `\inhibitglue【'.
-
-	   On the other hand, in \LuaTeX-ja, the process is done inside
-	   |hpack_filter| and |pre_linebreak_filter| callbacks. Hence,
-	   \emph{anything that does not make any node will be
-	   ignored}\ in \LuaTeX-ja, as shown in (1) in
-	   Table~\ref{tab-jfmglue}. \LuaTeX-ja also ignores any nodes
-	   which does not make any contribution to current horizontal
-	   list---\emph{ins\_node}, \emph{adjust\_node},
-	   \emph{mark\_node}, \emph{whatsit\_node} and
-	   \emph{penalty\_node}---, as shown in (4).
-
-
-By the way, around a \emph{glyph\_node} $p$ there may be some nodes
-	   attached to~$p$. These are an accent and kerns for
-	   moving it to the right place, and a kern from the italic
-	   correction\footnote{\TeX82 (and \LuaTeX) does not distinguish
-	   between explicit kern and a kern for italic correction. To
-	   distinguish them, an additional subtype for a kern is introduced
-	   in \pTeX. On the other hand, \LuaTeX-ja uses an additional attribute and
-	   redefines \texttt{\char`\\/} to set this attribute.} for $p$. It is natural that
-	   these attachments should be ignored inside the process. Hence
-	   \LuaTeX-ja takes this approach, as the latest version of
-	   \pTeX\ (version~p3.2). This explains (2) in the Table~\ref{tab-jfmglue}.
-
-Summerizing above, one should put an empty horizontal box |\hbox{}| to
-	   where he/she wants to interrupt the insertion process in
-	   \LuaTeX-ja as (3) in the Table~\ref{tab-jfmglue}.
-
-\item[Fonts with the same metric]
-Recall that \LuaTeX-ja separates `real' fonts and metrics, as in Subsection~\ref{ssec-sepmet}. 
-Consider the following input, where all Japanese fonts use same metric
-	   (in \LuaTeX-ja), and |\gt| selects \emph{gothic} family for
-	   the current Japanese font family:
-\begin{quote}
-\begin{verbatim}
-明朝）\gt （ゴシック
-\end{verbatim}
-\end{quote}
-If the above input is processed by \pTeX, because the insertion process is
-	   interrupt by |\gt|, the result looks like
-\begin{quote}
-\mc 明朝）\hbox{}\gt （ゴシック
-\end{quote}
-However this seems to be unnatural, since two Japanese fonts in the
-	   output use the same metric, i.e.,~the same
-	   typesetting rule.  Hence, we decided that Japanese fonts with
-	   the same metric are treated as one font in the insertion
-	   process of \LuaTeX-ja. Thus, the output from the above input
-	   in \LuaTeX-ja looks like:
-\begin{quote}
-\mc 明朝）\gt （ゴシック
-\end{quote}
-One might have the situation that this default behavior is not
-	   suitable. \LuaTeX-ja offers a way to handle this situation, but
-	   we leave it to the manual~\cite{man}.
-
-\item[Fonts with different metrics] 
-The case where two consecutive Japanese characters use different metrics and/or
-	   different size is similar. Consider the following input where
-	   the \emph{mincho} family and the \emph{gothic} family use
-	   different metrics:
-\begin{quote}
-\begin{verbatim}
-漢）\gt （漢）\large （大
-\end{verbatim}
-\end{quote}
-As the previous paragraph, this input yields the following, by \pTeX:
-\begin{quote}
-\mc 漢）\hbox{}\gt （漢）\hbox{}\large （大
-\end{quote}
-We had thought that amounts of spaces between parentheses in above output
-	   are too much. Hence we have changed the default behavior of
-	   \LuaTeX-ja, so that the amount of a glue between two Japanese
-	   characters with different metrics is the \emph{average} of a glue
-	   from the left character and that from the right
-	   character. For example, Figure~\ref{fig-diffmet} shows the
-	   output from above input. The width of glue indicated `(1)' is
-	   $(a/2 + a/2)/2 = 0.5a$, and the width of glue indicated `(2)'
-	   is $(a/2 + 1.2a/2)/2 = 0.55a$. This default behavior can be
-	   changed by \textsf{diffrentmet} parameter of \LuaTeX-ja.
-
-\begin{figure}
-\begin{center}
-\fontsize{40}{40}\selectfont
-\imagfm{\jstrut\smash{%
-  \vtop{\lineskiplimit=\maxdimen\lineskip2pt\halign{#\cr漢\cr
-    \small\vrule height .5ex depth .5ex\hrulefill\ \lower.5ex\hbox{$a$}\ 
-    \hrulefill\vrule height .5ex depth .5ex\cr}}}}%
-\imagfm{\jstrut ）\inhibitglue}%
-\hbox to .5\zw{\hss\normalsize (1)\hss}%
-\imagfm{\jstrut\inhibitglue\gt （}%
-\imagfm{\jstrut\gt 漢}%
-\imagfm{\jstrut\gt ）\inhibitglue}%
-\hbox to .55\zw{\hss\normalsize (2)\hss}%
-\imagfm{\fontsize{48}{48}\selectfont\jstrut\gt\inhibitglue （}%
-\imagfm{\fontsize{48}{48}\selectfont\jstrut\smash{%
-  \vtop{\lineskiplimit=\maxdimen\lineskip2pt\halign{#\cr\gt 大\cr
-    \small\vrule height .5ex depth .5ex\hrulefill\ \lower.5ex\hbox{$1.2a$}\ 
-    \hrulefill\vrule height .5ex depth .5ex\cr}}}}
-\end{center}
-\caption{Fonts with different metrics.}
-\label{fig-diffmet}
-\end{figure}
-
-\item[\emph{kanjiskip} and \emph{xkanjiskip}]
-In \pTeX, the value of \emph{xkanjiskip} is controlled by a skip named
-	   |\xkanjiskip|. A well-known defect of this implementation is
-	   that the value of \emph{xkanjiskip} is not connected with the
-	   size of the currnt Japanese font. It seems that |EXTRASPACE|,
-	   |EXTRASTRETCH|, |EXTRASHRINK| parameters in a JFM are
-	   reserved for specifying the default value of
-	   \emph{xkanjiskip} in a unit of the design size, but \pTeX\
-	   did not use these parameters, actually.
-
-Considering this situation of p\TeX, \LuaTeX-ja can use the value of
-	   \emph{xkanjiskip} that specified in a metric. If the value of
-	   \emph{xkanjiskip} on user side (this is the value of 
-	   \textsf{xkanjiskip} parameter of |\ltjsetparameter|) is
-	   |\maxdimen|, then \LuaTeX-ja use the specification from
-	   the current used metric as the actual value of
-	   \emph{xkanjiskip}. This description also applies for \emph{kanjiskip}.
-\end{description}
-
-\section{Distinction of characters}
-\label{sec:distinction_of_characters} Since \LuaTeX\ can handle Unicode
-characters natively, it is a major problem that how we distinguish
-Japanese characters and alphabetic characters. For example, the
-multiplication sign (U+00D7) exists both in ISO-8859-1 (hence in Latin-1
-Supplement in Unicode) and in the basic Japanese character set
-JIS~X~0208. It is not desirable that this character is always treated as
-an alphabetic character, because this symbol is often used in the sense
-of `negative' in Japan.
-
-\subsection{Character ranges}
-Before we describe the approach taken is \LuaTeX-ja, we review the
-approach taken by u\pTeX.  u\pTeX\ extends the |\kcatcode| primitive in
-\pTeX, to use this primitive for setting how a character is treated
-among alphabetic characters~(15), \emph{kanji}~(16), \emph{kana}~(17),
-\emph{kanji}, \emph{Hangul}~(17), or~\emph{other CJK characters}~(18).
-The assignment to |\kcatcode| can be done by a Unicode
-block.\footnote{There are some exceptions. For example, U+FF00--FFEF
-(Halfwidth and Fullwidth Forms) are divided into three blocks in recent
-u\pTeX.}
-
-\LuaTeX-ja adopted a different approach. There are many Unicode blocks
-	   in Basic Multilingual Plane which are not included in
-	   Japanese fonts, therefore it is inconvenient if we process by a Unicode
-	   block.  Furthermore, JIS~X~0208 are not just union of Unicode
-	   blocks; for example, the intersection of JIS~X~0208 and
-	   Latin-1 Supplement is shown in
-	   Table~\ref{tab-inter}. Considering these two points, to
-	   customize the range of Japanese characters in \LuaTeX-ja, one
-	   has to define ranges of character codes in his source in advance.
-
-
-\begin{table}
-\caption{Intersection of JIS~X~0208 and Latin-1 Supplement.}
-\label{tab-inter}
-\begin{center}
-\begin{tabular}{llll}
-\ltjjachar"A7 (U+00A7),&
-\ltjjachar"A8 (U+00A8),&
-\ltjjachar"B0 (U+00B0),&
-\ltjjachar"B1 (U+00B1),\\
-\ltjjachar"B4 (U+00B4),&
-\ltjjachar"B6 (U+00B6),&
-\ltjjachar"D7 (U+00D7),&
-\ltjjachar"F7 (U+00F7)
-\end{tabular}
-\end{center}
-\end{table}
-
-
-We note that \LuaTeX-ja offers two additional control sequences,
-      |\ltjjachar| and |\ltjalchar|. They are similar to |\char|
-      primitive, however |\ltjjachar| always yields a Japanese character, provided that
-      the argument is more than or equal to 128, and |\ltjalchar| always
-      yields an alphabetic character, regardless of the argument. 
-
-\subsection{Default setting of ranges}
-Patches for plain \TeX\ and \LaTeXe\ of \LuaTeX-ja predefine 8~character
-ranges, as shown in Table~\ref{tab-chrrng}.  Almost of these ranges are
-just the union of Unicode blocks, and determined from the Adobe-Japan1-6
-character collection~\cite{aj16}, and JIS~X~0208. Among these 8~ranges,
-the ranges~2, 3, 6, 7, and~8 are considered ranges of Japanese
-characters, and others are considered ranges of alphabetic
-characters.\footnote{Note that ranges 3~and~8 are considered ranges of
-alphabetic characters in this paper.}  We remark on ranges 2~and~8:
-\begin{description}
-\item[The range~2]
-JIS~X~0208 includes Greek letters and Cyrillic letters, however, these
-	   letters cannot be used for typesetting Greek or Russian, of
-	   course. Hence it is reasonable that Greek letters and
-	   Cyrillic consist another character range.
-\item[The range~8] 
-If one want to use 8-bit TFMs, such as T1 or TS1 encodings, he should
-	   mark this range~8 as a range of alphabetic characters by
-\begin{quote}
-|\ltjsetparameter{jacharrange={-8}}|
-\end{quote}
-This is because some 8-bit TFMs have a glyph in this range; for example,
-	   the character `\OE' is located at |"D7| in the T1 encoding. %"
-\end{description}
-
-
-\begin{table}
-\caption{Predefined ranges in \LuaTeX-ja.}
-\label{tab-chrrng}
-\begin{center}
-\begin{tabular}{@{\bf}rl}
-1&(Additional) Latin characters which are not belonged in the range~8.\\
-2&Greek and Cyrillic letters.\\
-3&Punctuations and miscellaneous symbols.\\
-4&Unicode blocks which does not intersect with Adobe-Japan1-6.\\
-5&Surrogates and supplementary private use Areas.\\
-6&Characters used in Japanese typesetting.\\
-7&Characters possibly used in CJK typesetting, but not in Japanese.\\
-8&Characters in Table~\ref{tab-inter}.
-\end{tabular}
-\end{center}
-\end{table}
-
-\subsection{Control sequences producing Unicode characters}
-\label{ssec-unichar}
-
-The \emph{fontspec} package\footnote{Preciously saying, it is the
-\emph{xunicode} package, originally a package for \XeTeX and
-automatically loaded by the \emph{fontspec} package.} offers various
-control sequences that produce Unicode characters.  However, these
-control sequences as it stands cannot work correctly with the default
-range setting of \LuaTeX-ja.  For example, |\textquotedblleft| is just
-an abbreviation of |\char"201C\relax|, and the character U+201C (LEFT %"
-DOUBLE QUOTATION MARK) is treated as an Japanese character, because it
-belongs to the range~3.  This problem is resolved by using |\ltjalchar|
-instead of the |\char| primitive.  It is included in an optional package
-named \texttt{luatexja-\penalty0fontspec.sty}.  Figure~\ref{fig-unitxt}
-shows several ways o typeset a character , both as a Japanese character
-and as as an alphabetic characters.
-
-\begin{figure}
-\begin{LTXexample}
-×, \char`×,   % depend on range setting 
-\ltjalchar`×, % alphabetic char
-\ltjjachar`×, % Japanese char
-\texttimes     % alph. char (by fontspec)
-\end{LTXexample}
-\caption{Control sequences producing a Unicode character.}
-\label{fig-unitxt}
-\end{figure}
-
-The situation looks similar in math formulas, but in fact it differs.
-Each control sequence that represents an ordinary symbol defined by the
-\emph{unicode-math} package is just synonym of a character. For example,
-the meaning of |\otimes| is just the character U+2297 (CIRCLED TIMES),
-which is included in the range~3.  However, it is difficult to define a
-control sequence like |\ltjalUmathchar| as a counterpart of
-|\Umathchar|, since an input like `|\sum^\ltjalUmathchar ...|' has to be
-permitted.
-
-However, we couldn't develop a satisfactory solution to this problem in
-time for this paper, due to a lack of time. We are just testing a
-solution below:
-\begin{itemize}
-\item \LuaTeX-ja has a list of character codes which will be always reated as
-      alphabetic characters in math mode. Considering 8-bit TFMs for
-      math symbols, this list includes natural numbers between |"80| and
-      |"FF| by default.
-\item Redefine internal commands defined in the \emph{unicode-math}
-      package so that
-codes of characters which are mentioned in the \emph{unicode-math}
-      package will be included in the list.
-\end{itemize}
-
-
-We would like to extend treatments described in this subsection to 8-bit
-font encodings, but we leave it to further development too.
-
-\section{Current status of development}
-\label{sec:current_status}
-At the moment, \LuaTeX-ja can be used under plain \TeX, and under
-\LaTeXe. Generally speaking, one only has to read |luatexja.sty|, by
-|\input| command or |\usepackage| (in~\LaTeXe), if you merely want to
-typeset Japanese characters.  We look more detail by parts. 
-
-\subsection{`Engine extension'}
-The lowest part of \LuaTeX-ja corresponds to the \pTeX\ extension as
-\emph{an engine extension of \TeX}. We, the project menbers, think that
-this part is almost done. There is one more feature of \LuaTeX-ja which
-we are going to explain:
-
-\begin{description}
-\item[Shifting baseline]
-In order to make a match between Japanese fonts and alphabetic fonts,
-	   sometimes shifting the baseline of alphabetic characters may
-	   be needed. \pTeX\ has a dimension |\ybaselineshift|, which
-	   corresponds to the amount of shifting down the baseline of alphabetic
-	   characters. This is useful for Japanese-based documents, but
-	   not for documents mainly in languages with alphabetic
-	   characters.
-
-Hence, \LuaTeX-ja extends \pTeX's |\ybaselineshift| to Japanese
-	   characters. Namely, \LuaTeX-ja offers two parameters,
-	   \textsf{yjabaselineshift} and \textsf{yalbaselineshift}, for the
-	   amount of shifting the baseline of Japanese characters and
-	   that of alphabetic characters, respectively. 
-\begin{figure}
-\begin{center}
-\fontsize{40}{40}\selectfont\fboxsep0mm
-\vrule width 0.9\textwidth height0.4pt depth0.4pt\kern-0.9\textwidth
-\hbox to 0.9\linewidth{%
-\hfil
-\raise-10pt\imagfm{\jstrut 漢}%
-\raise-10pt\imagfm{\jstrut 字}\hskip.25\zw%
-\imagfm{p}%
-\imagfm{h}%
-\hfil\hfil
-\imagfm{\jstrut 漢}%
-\imagfm{\jstrut 字}\hskip.25\zw%
-\raise-10pt\imagfm{p}%
-\raise-10pt\imagfm{h}%
-\hfil
-}
-\end{center}
-
-\caption{First example of shifting baseline.}
-\label{fig-bls}
-\end{figure}
-
-\begin{figure}
-\begin{center}
-\fontsize{30}{30}\selectfont\fboxsep0mm
-\vrule width 0.9\textwidth height0.4pt depth0.4pt\kern-0.9\textwidth
-\hbox to 0.9\linewidth{%
-\hfil
-\imagfm{a}%
-\imagfm{b}\hskip.25\zw%
-\imagfm{\jstrut 本}%
-\imagfm{\jstrut 文}\hskip.33333\zw%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut\inhibitglue （}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut 注}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut 釈}\hskip.1666667\zw%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont c}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont o}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont m}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont m}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont e}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont n}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont t}%
-\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut ）\inhibitglue}%
-\hskip.33333\zw%
-\imagfm{\jstrut 本}%
-\imagfm{\jstrut 文}%
-\hfil
-}
-\end{center}
-
-\caption{Second example of shifting baseline.}
-\label{fig-small}
-\end{figure}
-
-An example output is shown in Figure~\ref{fig-bls}. The left half is the
-	   output when \textsf{yjabaselineshift} is positive, hence the
-	   baseline of Japanese characters is shifted down. On the other
-	   hand, the right half is the output when
-	   \textsf{yalbaselineshift} is positive, hence the baseline of
-	   alphabetic characters is shifted down. Figure~\ref{fig-small}
-	   shows an intresting use of these parameters.
-
-\end{description}
-Note that \LuaTeX-ja doesn't support vertical typesetting, \emph{tategaki}, for now. 
-
-\subsection{Patches for plain \TeX\ and \LaTeXe}
-\pTeX\ has a patch for plain \TeX, namely |ptex.tex|, that for \LaTeXe\
-macro (this patch and \LaTeXe\ consist \emph{p\LaTeXe}), and
-|kinsoku.tex| which includes the default setting of \emph{kinsoku
-shori}, the Japanese hyphenation.  We ported them to \LuaTeX-ja, except
-the codes related to vertical typesetting, because \LuaTeX-ja doesn't
-support vertical typesetting yet. We remark one point related to the
-porting:
-\begin{description}
-
-\item[Behavior of\/ {\tt\char92fontfamily\/}]
-The control sequence |\fontfamily| in p\LaTeXe\ changes the current alphabetic
-	   font family and/or the current Japanese font family,
-	   depending the argument. More concretely,
-	   |\fontfamily{|$\langle\hbox{\it arg\/}\rangle$|}| changes the
-	   current alphabetic font family to $\langle\hbox{\it
-	   arg\/}\rangle$, if and only if one of the following
-	   conditions are satisfied:
-\begin{itemize}
-\item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$ in
-      \emph{some} alphabetic encoding is already defined in the document.
-\item There exists an alphabetic encoding $\langle\hbox{\it
-      enc\/}\rangle$ already defined in the document such that a font
-      definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it
-      arg\/}\rangle$|.fd| (all lowercase) exists.
-\end{itemize}
-The same criterion is used for changing Japanese font family.
-
-To work this behavior well, a list of all (alphabetic) encodings defined
-	   already in the document is needed. However, since \LuaTeX-ja
-	   is loaded as a package, \LuaTeX-ja cannot have this list.
-	   Hence \LuaTeX-ja adopted a different approach, namely
-	   |\fontfamily{|$\langle\hbox{\it arg\/}\rangle$|}| changes the
-	   current alphabetic font family to $\langle\hbox{\it
-	   arg\/}\rangle$, if and only if:
-\begin{itemize}
-\item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$
-      in the current alphabetic encoding $\langle\hbox{\it
-      enc\/}\rangle$ is already defined in the document.
-\item A  font definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it
-      arg\/}\rangle$|.fd| (all lowercase) exists.
-\end{itemize}
-
-
-\end{description}
-
-
-
-\subsection{Classes for Japanese documents}
-To produce `high-quality' Japanese documents, we need not only that
-Japanese characters are correctly placed, but also class files for
-Japanese documents. Two major families of classes are widely used in Japan:
-\emph{jclasses} which is distributed with the official p\LaTeXe\ macros,
-and \emph{jsclasses}.  At the present, \LuaTeX-ja
-simply contains their counterparts: \emph{ltjclasses} and
-\emph{ltjsclasses}. However, the policy on classes is not determined
-now, and we hope to have another family of classes which are useful for
-commercial printing.  In the author's opinion, \emph{ltjclasses} is
-better to stay as an example of porting of class files for \pTeX\ to
-\LuaTeX-ja.
-
-\subsection{Patches for packages}
-Apart from patches for the \LaTeXe~kernel and classes for Japanese
-documents, we need to make patches for several packages. At the present,
-we considered the following packages, and made patches or porting for
-the former two packages.
-
-\begin{description}
-\item[The \emph{fontspec} package] The \emph{fontspec} package is built
-	   on NFSS2, hence control sequences offered by the
-	   \emph{fontspec} package, such as |\setmainfont|, are only
-	   effective for alphabetic fonts if \LuaTeX-ja is loaded.
-	   \texttt{luatexja-\penalty0fontspec.sty} (not automatically
-	   loaded) offers these counterparts for Japanese fonts, with
-	   additional `j' in the name of control sequences, such as
-	   |\setmainjfont|. As described in
-	   Subsection~\ref{ssec-unichar}, it also includes a patch for
-	   control sequences producing Unicode characters.
-
-\item[The \emph{otf} package]
-This package is widely used in \pTeX\ for typesetting characters which is
-not in JIS~X~0208, and for using more than one weight in \emph{mincho}
-and \emph{gothic} font families. Therefore \LuaTeX-ja supports features
-in the \emph{otf} package, by loading \texttt{luatexja-\penalty0otf.sty}
-	   manually. Note that characters by |\UTF{xxxx}| and
-	   |\CID{xxxx}| are not appended to the current list as a
-	   \emph{glyph\_node}, to avoid from callbacks by the
-	   \emph{luaotfload} package. We have another remark; |\CID|
-	   does not work with TrueType fonts, since |\CID| use the
-	   conversion table between CID and the glyph order of the
-	   current Japanese font.
-
-\item[The \emph{listings} package]
-It is known for users of \pTeX\ that there is a patch |jlisting.sty| for
-	   the \emph{listings} package, to use Japanese characters in
-	   the |lstlisting| environment. Generally speaking, it also can
-	   be used in \LuaTeX-ja. However, it seems to be that a
-	   Japanese character after a space does not recieve any process
-	   of the \emph{listings} package; this is inconvinient when we
-	   use the \emph{showexpl} package.
-
-There is another way to use characters above 256 with the
-	   \emph{listings} package (described in\cite{apl}). However,
-	   this method is not suitable for Japanese, since the number of
-	   Japanese characters is very large. We hope that the
-	   \emph{listings} package will be able to handle all characters above
-	   256 without any patch, in the future.
-
-
-\end{description}
-
-
-
-\section{Implementation}
-\label{sec:implementation}
-\subsection{Handling of Japanese fonts}
-In \pTeX, there are three slots for maintaining current fonts, namely
-|\font| for alphabetic fonts, |\jfont| for Japanese fonts (in horizontal
-direction) and |\tfont| for Japanese fonts (in vertical direction). With
-these slots, we can manage the current font for alphabetic characters
-and that for Japanese characters separately in \pTeX.  However, \LuaTeX\
-has only one slot for maintaining the current font, as \TeX82.  This
-situation leads a problem: how can we maintain the `current Japanese
-font'?
-
-There are three approaches for this problem. One approach is to make a
-mapping table from alphabetic fonts to corresponding Japanese fonts
-(here we don't assume that NFSS2 is available).  Another approach is
-that we always use composite fonts with alphabetic fonts and Japanese
-fonts. The third approach is that the information of the current
-Japanese font is stored in an attribute. We adopted the third approach,
-since \LuaTeX-ja is much affected by \pTeX\ as we noted in
-Subsection~\ref{ssec-pol}.
-
-As in Figure~\ref{fig-jfdef}, \LuaTeX-ja uses |\jfont| for defining
-Japanese fonts, as \pTeX.  However, because the information of the current
-Japanese font is stored into an attribute, control sequences defined by
-|\jfont| (e.g.,~|\foo| and |\bar| in Figure~\ref{fig-jfdef}) is
-not representing a font by the means of \TeX82. In other words, each of
-these control sequences is just an assignment to an attribute, therefore
-they cannot be an argument of |\the|, |\fontname|, nor |\textfont|.
-
-
-Callbacks by the \emph{luaotfload} package, e.g.,~replacement of glyphs
-according to OpenType font features, are performed just after `Examination of
-stack level' (see Subsections
-\ref{ssec-over}~and~\ref{ssec-stack}). Also note that calculation of
-character classes for each Japanese character is done \emph{after} the
-these callbacks for now. 
-
-\subsection{Stack management}
-\label{ssec-stack}
-
-As we noted in Subsection~\ref{ssec-csname}, parameters that the values
-at the end of a horizontal box or that of a paragraph are valid in
-whole box or paragraph, such as \emph{kanjiskip}, cannot be implemented
-by internal integers or registers of other types in \TeX. We explain it
-in this subsection.
-
-\begin{figure}
-\begin{lstlisting}
-void package(int c)
-{
-    ...
-    d = box_max_depth;
-    unsave();
-    save_ptr -= 4;
-    if (cur_list.mode_field == -hmode) {
-        cur_box = filtered_hpack(cur_list.head_field,
-                                 cur_list.tail_field, saved_value(1),
-                                 saved_level(1), grp, saved_level(2));
-        subtype(cur_box) = HLIST_SUBTYPE_HBOX;
-    } else {
-\end{lstlisting}
-\caption{An extract of a CWEB-source \texttt{tex/packaging.w} of \LuaTeX.}
-\label{fig-ltsrc}
-\end{figure}
-
-Figure~\ref{fig-ltsrc} is an extract of a CWEB-source
-\texttt{tex/packaging.w} of \LuaTeX\ (SVN revision 4358). This function
-is called just when an explicit |\hbox{...}| or |\vbox{...}| is ended, and
-the function |filtered_hpack()| is where the |hpack_filter| and then the
-actual `hpack' process are performed. Notice that the |unsave()|
-function is called before |filtered_hpack()|. This is the problem;
-because of |unsave()|, we can retrive only the values of registers
-\emph{outside} the box, even in the |hpack_filter| callback.
-
-To cope with this problem, \LuaTeX-ja has its own stack system, based on
-Lua codes in \cite{stack-mail}. Furthermore, \emph{whatsit} nodes whose
-\emph{user\_id} is 30112 (\emph{stack\_node}, for short) will be
-appended to the current horizontal list each time the current stack
-level is incremented, and their values are the values of
-|\currentgrouplevel| at that time. In the beginning of the |hpack_filter|
-callback, the list in question is traversed to determine whether the
-stack level at the end of the list and that outside the box coincides.
-
-Let $x$ be the value of |\currentgrouplevel|, and $y$ be the current
-stack level, both inside the |hpack_filter| callback, i.e.,~outside a
-horizontal box. Consider a list which represents the content of the box,
-then we have:
-\begin{itemize}
-\item A \emph{stack\_node} whose value is $x+1$ (because all materials
-      in the box are included in a group |\hbox{...}|, the value of
-      |\currentgrouplevel| inside the box is at least $x+1$) in the list
-      corresponds to an assignment related to the stack system in just
-      top-level of the list, like
-\begin{quote}
-\begin{verbatim}
-\hbox{...(assignment)...}
-\end{verbatim}
-\end{quote}
-In this case, the current stack level is incremented to $y+1$ after the assignment.
-\item A \emph{stack\_node} whose value is more than  $x+1$ in the list corresponds
-to an assignment inside another group contained in the box. For example,
-      the following input creates
-a \emph{stack\_node} whose value is $x+3=(x+1)+2$:
-\begin{quote}
-\begin{verbatim}
-\hbox{...{...{...(assignment)}...}...}
-\end{verbatim}
-\end{quote}
-\end{itemize}
-Thus, we can conclude that the stack level at the end of the list is
-$y+1$, if and only if there is a \emph{stack\_node} whose value is
-$x+1$. Otherwise, the stack level is just $y$.
-
-\subsection{Adjustment of the position of Japanese characters}
-\label{ssec-width}
-
-The size of a glyph specified in a metric and that of a real font
-usually differ. For example, the letter `\inhibitglue【' is half-width
-in |jfm-ujis.lua| or |jis.tfm|, while this letter is full-width like `【'
-in most TrueType fonts used in Japanese typesetting, such as
-IPA~Mincho. Hence the adjustment of position of such glyphs is
-needed. In the context of \pTeX, this process was performed using virtual fonts.
-
-On the other hand, Lua\TeX-ja does the adjustment by encapsuling a glyph
-into a horizontal box. There are two main reasons why we adopted this
-method; one is that we feared Lua codes for coexisting with callbacks by
-the |luaotfload| package would be large if we use virtual fonts, and the
-other is to cope with shifting of the baseline of characters at the
-same time. 
-
-\begin{figure}
-\begin{center}\unitlength=9pt\small
-\begin{picture}(15,12)(-1,-3)
-
-\color{grayx}% real glyph
-\put(-1,-1.5){\vrule width 6\unitlength height 7\unitlength depth 2.5\unitlength}
-
-\color{black}% real glyph :step1
-\thicklines
-\put(-1,-1.5){\line(0,1){7}\line(0,-1){2.5}}
-\put(5,-1.5){\line(0,1){7}\line(0,-1){2.5}}
-\put(-1,5.5){\line(1,0){6}}
-\put(-1,-4){\line(1,0){6}}
-\put(-1,0){\makebox(0,0)[r]{\strut$R$\,}}
-
-\thicklines
-\put(0,0){\vector(0,1){9}\line(0,-1){3}\vector(1,0){12}}
-\put(12,9){\makebox(0,0)[rt]{\strut$M$\,}}
-\put(12,0){\line(0,1){9}\vector(0,-1){3}}
-\put(0,9){\line(1,0){12}}
-\put(0,-3){\line(1,0){12}}
-\put(0.2,4.5){\makebox(0,0)[l]{\texttt{height}}}
-\put(12.2,-1.5){\makebox(0,0)[l]{\texttt{depth}}}
-\put(6,0.2){\makebox(0,0)[b]{\texttt{width}}}
-
-\thicklines
-\put(3,0){\line(0,1){7}\line(0,-1){2.5}\line(1,0){6}}
-\put(9,0){\line(0,1){7}\line(0,-1){2.5}}
-\put(3,7){\line(1,0){6}}
-\put(3,-2.5){\line(1,0){6}}
-\newsavebox{\eqdist}
-\savebox{\eqdist}(0,0)[c]{%
-  \thinlines
-  \put(-0.08,0.2){\line(0,-1){0.4}}%
-  \put(0.08,0.2){\line(0,-1){0.4}}}
-\put(1.5,0){\usebox{\eqdist}}
-\put(10.5,0){\usebox{\eqdist}}
-
-\thicklines
-\put(3,-1.5){\vector(-1,0){4}}
-\put(1,-1.7){\makebox(0,0)[t]{\texttt{left}}}
-\put(3,0){\vector(0,-1){1.5}}
-\put(3.2,-0.75){\makebox(0,0)[l]{\texttt{down}}}
-\end{picture} 
-\end{center}
-\caption{The position of the `real' glyph.}
-\label{fig-pos}
-\end{figure}
-
-Figure~\ref{fig-pos} shows the adjustment process. A large square $M$ is
-the imaginary body specified in the metric, and a vertical
-rectangle is the imaginary body of a real glyph. First, the real glyph
-is aligned with respect to the width of $M$. In the figure, the real
-glyph is aligned `middle'; this setting is useful for the full-width
-middle dot `・'. We have other settings, `left' and `right'.
-After that, it is shifted according to the value of |left| and |down|,
-which are specified in the metric, too. The final position of the real glyph
-is shown by the gray rectangle~$R$. If the amount of shifting the baseline is
-not zero, $M$ (and hence the real glyph) is shifted by that amount.
-
-We would like to remark briefly on the vertical position of a real
-glyph.  A JFM (or a metric used in \LuaTeX-ja) and a real font used for
-it may have different height or depth.  In that case, it may look better
-if the real glyph is shifted vertically to match the height-depth ratio
-specified in the metric, while any vertical adjustment except the
-adjustment by the |down| value does not performed in the present
-implementation of \LuaTeX-ja . This situation is carefully studied by
-Otobe~\cite{min10}. Here the policy on this problem is not determined
-now, however we would like to offer several solutions in future
-development.
-
-\section{Conclusion}
-We have discussed about our \LuaTeX-ja package, which is much affected
-by \pTeX. For now, it can be used for experimental use, however there
-are much refinements which are needed for regular use. The author hopes
-that this paper and \LuaTeX-ja project contribute the typesetting Japanese,
-and possibly other Asian languages, under \LuaTeX.
-
-\section*{Acknowledgements}
-The author would like to thank Ken Nakano and Hideaki Togashi for their
-development of ASCII \pTeX.  The author is very grateful to Haruhiko
-Okumura for his leadership in the Japanese \TeX\ community. The author
-is also very grateful to members of \LuaTeX-ja project team for their
-valuable cooperation in development.
-
-%%% The style of the bibiliogrphy is `amsplain'.
-\providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}
-\providecommand{\href}[2]{#2}
-\begin{thebibliography}{99}
-
-\bibitem{aj16}
-Adobe Systems Incorporated, \emph{Adobe-Japan1-6 Character Collection
-	for CID-Keyed Fonts}, Technical Note~\#5078, 2004.
-\url{http://partners.adobe.com/public/developer/en/font/5078.Adobe-Japan1-6.pdf}
-
-\bibitem{ptex}
-ASCII MEDIA WORKS，アスキー日本語\TeX\ (\pTeX)．\url{http://ascii.asciimw.jp/pb/ptex/}
-
-\bibitem{apl}
-John Baker, \emph{Typesetting UTF8 APL code with the \LaTeX\ lstlisting package}.
-\url{http://bakerjd99.wordpress.com/2011/08/15/}
-
-\bibitem{omega}
-Jin-Hwan~Cho and Haruhiko Okumura, \emph{Typesetting CJK Languages with Omega},
-\TeX, XML, and Digital Typography, Lecture Notes in Computer Science, vol.~3130,
-Springer, 2004, 139--148.
-
-\bibitem{joylua}
-Yannis Haralambous. \emph{The Joy of \LuaTeX}. \url{http://luatex.bluwiki.com/}
-
-\bibitem{jisx4051}
-Japanese Industrial Standards Committee. \emph{JIS~X~4051: Formatting
-	rules for Japanese documents}, 1993, 1995, 2004.
-
-\bibitem{eptex}
-北川弘典，$\varepsilon$-\pTeX についてのwiki．
-\url{http://sourceforge.jp/projects/eptex/wiki/FrontPage}
-
-\bibitem{luaums}
-北川弘典，\LuaTeX で日本語．
-\url{http://oku.edu.mie-u.ac.jp/tex/mod/forum/discuss.php?d=378}
-
-\bibitem{luatexref}
-\LuaTeX\ development team, \emph{The \LuaTeX\ reference}. 
-\url{http://www.luatex.org/svn/trunk/manual/luatexref-t.pdf} (snapshot of SVN trunk)
-
-\bibitem{man}
-\LuaTeX-ja project team, \emph{The \LuaTeX-ja package}. 
-Not completed for now. Available at |doc/man-en.pdf| (in English) or
-	|doc/man-ja.pdf| (in Japanese)
-in the Git repository.
-
-\bibitem{luajp-test}
-香田温人，\LuaTeX と日本語．
-\url{http://www1.pm.tokushima-u.ac.jp/~kohda/tex/luatex-old.html}
-
-\bibitem{luajalayout}
-前田一貴，luajalayout パッケージ---Lua\LaTeX によ
-	る日本語組版---．
-\url{http://www-is.amp.i.kyoto-u.ac.jp/lab/kmaeda/lualatex/luajalayout/}
-
-\bibitem{jsclasses}
-奥村晴彦，p\LaTeXe 新ドキュメントクラス．
-\url{http://oku.edu.mie-u.ac.jp/~okumura/jsclasses/}
-
-\bibitem{ptexjp}
-Haruhiko Okumura, \emph{\pTeX\ and Japanese Typesetting},
-	The Asian Journal of \TeX\ \textbf{2}~(2008), 43--51.
-
-\bibitem{min10}
-乙部厳己，min10フォントについて．
-\url{http://argent.shinshu-u.ac.jp/~otobe/tex/files/min10.pdf}
-
-\bibitem{otf}
-齋藤修三郎，Open Type Font用VF．
-\url{http://psitau.kitunebi.com/otf.html}
-
-\bibitem{stack-mail}
-Jonathan Sauer, \emph{[Dev-luatex] tex.currentgrouplevel}. 
-\url{http://www.ntg.nl/pipermail/dev-luatex/2008-August/001765.html}
-
-\bibitem{uptex}
-Takuji Tanaka, \emph{u\pTeX, up\LaTeX---unicode version of \pTeX, p\LaTeX}.
-\url{http://homepage3.nifty.com/ttk/comp/tex/uptex_en.html}
-
-\bibitem{ptexenc}
-Nobuyuki Tsuchimura, \emph{Development of a Japanese \TeX\ Distribution~`ptetex3'},
-Computer Software\ \textbf{24} (2007), no.~4, 40--50, (in Japanese).
-
-\bibitem{w3c}
-W3C Working Group, \emph{Requirements for Japanese Text Layout}. 
-\url{http://www.w3.org/TR/jlreq/}
-\end{thebibliography}
-
-\end{document}
+%#!lualatex ajt-devel-ltja
+\documentclass{ajt}
+
+%%% Packages used in this paper
+
+%%% Font setting for \LuaTeX; this is extract from ajt.cls
+\makeatletter
+  \if@print
+    \RequirePackage{fontspec,xunicode}
+    \RequirePackage{luatextra}
+    \setmainfont[Mapping=tex-text]{Palatino LT Std}
+    \setsansfont[Mapping=tex-text]{Optima LT Std}
+  \else
+    \RequirePackage{fontspec,luatextra}
+    \setmainfont[Mapping=tex-text]{TeX Gyre Pagella} % \simeq Palatino
+  \fi
+
+%%% LuaTeX-ja
+\usepackage{luatexja,luatexja-fontspec}
+\ltjsetparameter{jacharrange={-3,-8}}
+\DeclareFontShape{JY3}{mc}{m}{n}{<-> s*[0.92489] file:ipam.ttf:jfm=ujis}{}
+\DeclareFontShape{JY3}{gt}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=ujis}{}
+% quick hack: monospaced Japanese font by \ttfamily
+\DeclareKanjiFamily{JY3}{\ttdefault}{}{}
+\DeclareFontShape{JY3}{\ttdefault}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=mono}{}
+
+
+%%% LTXexample environment
+\usepackage{showexpl,lltjlisting}
+\lstset{basicstyle=\ttfamily\small, width=0.3\textwidth,  basewidth=.5em}
+
+%%% Verbatim environment
+\usepackage{fancyvrb}
+\CustomVerbatimEnvironment{code}{Verbatim}%
+{numbers=left,xleftmargin=1.5em,baselinestretch=1.069,fontsize=\small}
+\CustomVerbatimEnvironment{codewithoutnum}{Verbatim}%
+{xleftmargin=1.5em,baselinestretch=1.069,fontsize=\small}
+\CustomVerbatimEnvironment{codewithoutnumsmall}{Verbatim}%
+{xleftmargin=1.5em,baselinestretch=1.0,fontsize=\footnotesize}
+\DefineShortVerb{\|}
+
+%%% Others
+\usepackage{mflogo,booktabs}
+\definecolor{grayx}{gray}{0.85}
+\hyphenation{
+  kanjiskip
+  xkanjiskip
+}
+
+%%% Mandatory article metadata %%%
+\title{Development of \LuaTeX-ja package}
+\author[北川 弘典]{Hironori Kitagawa}
+\address{\LuaTeX-ja project team}
+\email{h\[e-mail]}
+
+\keywords{\TeX, p\TeX, \LuaTeX, \LuaTeX-ja, Japanese}
+\abstract{%
+\LuaTeX-ja package is a macro package for typesetting Japanese
+documents under \LuaTeX.  The package has more flexibility of
+typesetting than \pTeX, which is widely used Japanese extension of \TeX,
+and has corrected some unwanted features of \pTeX.
+In this paper, we describe specifications, the current status and some
+internal processing methods of \LuaTeX-ja.
+}
+
+\newcommand{\parname}[1]{\textsf{#1}}
+\newcommand{\jstrut}{\vrule width0pt height\cht depth\cdp}
+\newcommand{\imagfm}[1]{\ifvmode\leavevmode\fi%
+  \hbox{\fboxsep=0pt\fbox{\setbox0=\hbox{#1}\copy0\kern-\wd0
+  \smash{\vrule width \wd0 height 0.4pt depth0.4pt}}}}
+\begin{document}
+
+%%% Do not forget to start with \maketitle!
+\maketitle
+
+\section{Introduction}
+\subsection{History}
+To typeset Japanese documents with \TeX, ASCII \pTeX~\cite{ptex} has
+been widely used in Japan.  There are other methods---for example, using
+Omega and OTP~\cite{omega}, or with the CJK package---to do so, however,
+these alternative methods did not become majority.  The author thinks
+that this is because \pTeX\ enables us to produce high-quality documents
+(e.g.,~supporting vertical typesetting), and the appearance of \pTeX\ is
+earlier than that of alternatives described above.
+
+However, \pTeX\ has been left behind from the extensions of \TeX\ such
+as \eTeX\ and \pdfTeX, and the diffusion of UTF-8 encoding.  In recent
+years, the situation has become better, by development of
+|ptexenc|~\cite{ptexenc} by Nobuyuki Tsuchimura (\hbox{土村展之}),
+$\varepsilon$-\pTeX~\cite{eptex} by the author,~and u\pTeX~\cite{uptex}
+by Takuji Tanaka (田中琢爾). However, continuing this approach, namely,
+to develop an engine extension localized for Japanese, is not wise. This
+approach needs lots of work for \emph{each} engine. In addition, if we
+use \LuaTeX, the necessity of an engine extension is getting smaller
+because \LuaTeX\ has an ability to hook \TeX's internal process by using
+Lua callbacks.
+
+
+There were several experimental attempts to typeset
+Japanese documents with \LuaTeX\ before. Here we cite three examples:
+\begin{itemize}
+\item |luaums.sty|~\cite{luaums} developed by the author. This
+      experimental package is for creating a certain Japanese-based presentation
+      with \LuaTeX.
+\item the \emph{luajalayout} package~\cite{luajalayout}, formerly known as the
+      \emph{jafontspec} package, by Kazuki Maeda (前田一貴). This package is based on
+      \LaTeXe\ and \emph{fontspec} package.
+\item the \emph{luajp-test} package~\cite{luajp-test}, a test package made by
+      Atsuhito Kohda (香田温人), based on articles on the web page~\cite{joylua}.
+\end{itemize}
+However, these packages are based on \LaTeXe, and do not have much
+ability to control the typesetting rule. And it is inefficient that more
+than one people separately develop similar packages.  Development of the
+\LuaTeX-ja package is started initially by the author and Kazuki Maeda, because of
+these situations.
+
+\subsection{Development policy of \LuaTeX-ja}
+\label{ssec-pol} 
+The first aim of \LuaTeX-ja project was to implement features (from the
+`primitive' level) of \pTeX\ as macros under \LuaTeX, therefore \LuaTeX-ja is
+much affected by \pTeX.  However, as development proceeded, some
+technical/conceptual difficulties arose. Hence we changed the aim
+of the project as follows:
+\begin{itemize}
+\item\emph{\LuaTeX-ja offers at least the same flexibility of
+     typesetting that p\TeX\ has.}
+
+     We are not satisfied with the ability of producing outputs conformed to
+     JIS~X~4051~\cite{jisx4051}, the Japanese Industrial Standard for
+     typesetting, or to a technical note~\cite{w3c} by W3C;
+     if one wants to produce very incoherent outputs for some reason, it
+     should be possible.
+In this point, previous attempts of Japanese typesetting with \LuaTeX\
+     which we cited in the previous subsection are inadequate.
+
+\pTeX\ has some flexibility of typesetting, by changing internal
+     parameters such as |\kanjiskip| or |\prebreakpenalty|, and by using
+     custom JFM (Japanese TFM). Therefore we decided to include these
+     functionality to \LuaTeX-ja.
+
+\item\emph{\LuaTeX-ja isn't mere re-implementation or porting of \pTeX;
+     some (technically and/or conceptually) inconvenient features of
+     \pTeX\ are modified.} 
+
+     We describe this point in more detail at the next section.
+\end{itemize}
+
+
+\subsection{Overview of the processes}
+\label{ssec-over}
+We describe an outline of \LuaTeX-ja's process in order.
+
+\begin{itemize}
+\item In the |process_input_buffer| callback: treatment of breaking
+      lines after a Japanese character (in Subsection~\ref{ssec-line}).
+
+\item In the |hyphenate| callback: font replacement.
+
+\LuaTeX-ja looks into for each \textit{glyph\_node}~$p$ in the horizontal list. If
+	   the character represented by $p$ is considered as a Japanese
+	   character, the font used at $p$ is replaced by the value of
+	   |\ltj@curjfnt|, an attribute for `the current Japanese font'
+	   at~$p$.
+
+Furthermore, the subtype of $p$ is subtracted by 1 to suppress
+	   hyphenation around $p$ by \LuaTeX, because later processes of
+	   \LuaTeX-ja take care of all things about Japanese characters.
+
+\item In |pre_linebreak_filter| and |hpack_filter| callbacks:
+
+\begin{enumerate}
+\item \LuaTeX-ja has its own stack system, and the current horizontal
+      list is traversed in this stage to determine what the level of
+      \LuaTeX-ja's internal stack at the end of the list is. We will
+      discuss it in Subsection~\ref{ssec-stack}.
+
+\item In this stage, \LuaTeX-ja inserts glues/kerns for Japanese
+      typesetting in the list. This is the core routine of \LuaTeX-ja.
+      We will discuss it in Subsections
+      \ref{ssec-jglue}~and~\ref{ssec-jspec} .
+
+\item To make a match between a metric and a real font, sometimes
+      adjustument of the position of (Japanese) glyphs are performed.
+      We will discuss it in Subsection~\ref{ssec-width}.
+\end{enumerate}
+\item In the |mlist_to_hlist| callback: treatment of Japanese characters
+      in math formulas. This stage is similar to adjustment of the
+      position of glyphs (see above), so we omit to describe this stage
+      from this paper.
+\end{itemize}
+
+In this paper, a \emph{alphabetic character} means a non-Japanese
+character. Similarly, we use the word an \emph{alphabetic font} as the
+counterpart of a jJpanese font.
+
+\subsection{Contents of this paper}
+Here we describe the contents of the rest of this paper briefly.  In
+Section~\ref{sec:differences_with_ptex}, we describe major differences
+between \pTeX\ and \LuaTeX-ja.  The next section,
+Section~\ref{sec:distinction_of_characters}, is concentrated on a
+problem how we distinguish between Japanese characters and alphabetic
+characters. In Section~\ref{sec:current_status}, we show current
+development status of the package.  Finally, in
+Section~\ref{sec:implementation}, we describe some internal routines of
+\LuaTeX-ja.
+
+\subsection{General information of the project}
+This \LuaTeX-ja project is hosted by SourceForge.jp. The official wiki
+is located on
+\url{http://sourceforge.jp/projects/luatex-ja/wiki/}.  There is
+no stable version on October 22, 2011, however a set of developer sources can be
+obtained from the git repository.  Members of the project team are as follows
+(in random order): Hironori Kitagawa, Kazuki Maeda, Takayuki Yato,
+Yusuke Kuroki, Noriyuki Abe, Munehiro Yamamoto, Tomoaki Honda,
+and~Shuzaburo Saito.
+
+
+\section{Major differences with \pTeX}
+\label{sec:differences_with_ptex}
+In this section, we explain several major differences between \pTeX\
+and our \LuaTeX-ja.  For general information of Japanese typesetting and the
+overview of \pTeX, please see Okumura~\cite{ptexjp}.
+
+
+\subsection{Names of control sequences}
+\label{ssec-csname} Because \pTeX\ is an engine modification of Knuth's
+original \TeX82 engine, some of the additional primitives take a form that is
+very difficult to be simulated by a macro.  For example, an additional
+primitive |\prebreakpenalty|$\langle\hbox{\it
+char\_code}\rangle$|[=]|$\langle\hbox{\it penalty}\rangle$ in \pTeX\
+sets the amount of penalty inserted before a character whose code is
+$\langle\hbox{\it char\_code}\rangle$ to $\langle\hbox{\it
+penalty}\rangle$, and this form |\prebreakpenalty|$\langle\hbox{\it
+char\_code}\rangle$ can be also used for retrieving the value.
+
+Moreover, there are some internal parameters of \pTeX\ which values of them at the end of a
+horizontal box or that of a paragraph are valid in whole box or
+paragraph.  However, the implementation of these parameters in
+\LuaTeX-ja is not so easy; we will discuss it in Subsection~\ref{ssec-stack}.
+
+From above two problems  discussed above, the assignment and retrieval
+of most parameters in \LuaTeX-ja are summarized into the following
+three control sequences:
+\begin{itemize}
+\item |\ltjsetparameter{|$\langle\hbox{\it
+      name}\rangle$|=|$\langle\hbox{\it value}\rangle$|,...}|: for local
+      assignment.
+\item |\ltjglobalsetparameter|: for global assignment. Note that these two control
+      sequences obey the value of |\globaldefs| primitive.
+\item |\ltjgetparameter{|$\langle\hbox{\it
+      name}\rangle$|}[{|$\langle\hbox{\it optional
+      argument}\rangle$|}]|: for retrieval. The returned value is always
+      a string.
+\end{itemize}
+
+\subsection{Line-break after a Japanese character}
+\label{ssec-line} 
+
+Japanese texts can break lines almost everywhere, in contrast with
+alphabetic texts can break lines only between words (or use
+hyphenation). Hence, \pTeX's input processor is modified so that a
+line-break after a Japanese character doesn't emit a space. However,
+there is no way to customize the input processor of \LuaTeX, other than
+to hack its CWEB-source. All a macro package can do is to modify an input line before
+when \LuaTeX\ begin to process it, inside the |process_input_buffer|
+callback.
+
+Hence, in \LuaTeX-ja, a comment letter (we reserve U+FFFFF for this
+purpose) will be appended to an input line, if this line ends with a Japanese
+character.\footnote{Strictly speaking, it also requires that the catcode
+of the end-line character is 5~(\emph{end-of-line}). This condition is
+useful under the verbatim environment.}  One might jump to a conclusion
+that the treatment of a line-break by \pTeX\ and that of \LuaTeX-ja are
+totally same, however they are different in the respect that \LuaTeX-ja's
+judgement whether a comment letter will be appended the line is done
+\emph{before} the line is actually processed by \LuaTeX.
+
+Figure~\ref{fig-linebreak} shows an example of this situation; the
+command at the first line marks most of Japanese characters as
+`non-Japanese characters'. In other words, from that command onward, the
+letter `あ' will be treated as an alphabetic character by
+\LuaTeX-ja. Then, it is natural to have a space between `あ' and `y' in
+the output, where the actual output in the figure does not so.  This is
+because `あ' is considered a Japanese character by \LuaTeX-ja,
+when \LuaTeX-ja does the decision whether U+FFFFF will be added to the
+input line~2.
+
+\begin{figure}
+\begin{LTXexample}
+\font\x=IPAMincho \x
+\ltjsetparameter{jacharrange={-6}}xあ
+y
+\end{LTXexample}
+\caption{A notable sample showing the treatment of a line-break after a
+Japanese character.}\label{fig-linebreak}
+\end{figure}
+
+\subsection{Separation between `real' fonts and metrics}
+\label{ssec-sepmet}
+
+Traditionally, most Japanese fonts used in typesetting are not
+proportional, that is, most glyphs have same size (in most cases,
+square-shaped). Hence, it is not rare that the contents of different
+JFMs are essentially same, and only differ in their names. For example,
+|min10.tfm| and |goth10.tfm|, which are JFMs shipped with \pTeX\ for
+seriffed \emph{mincho} family and sans-seriffed \emph{gothic} family,
+differ their |FAMILY| and |FACE| only. Moreover, |jis.tfm| and
+|jisg.tfm|, which is included in the \emph{jis} font metric, which is
+used in \emph{jsclasses}~\cite{jsclasses} by Haruhiko Okumura (奥村晴彦),
+are totally same as binary files.  Considering this situation, we
+decided to separate `real' fonts and metrics used for them in
+\LuaTeX-ja. Typical declarations of Japanese fonts in the style of plain
+\TeX\ are shown in Figure~\ref{fig-jfdef}. We would like to add several
+remarks:
+\begin{itemize}
+\item A control sequence |\jfont| must be used for Japanese fonts, instead of |\font|.
+\item \LuaTeX-ja automatically loads the \emph{luaotfload} package, so
+      \hbox{\tt file:} and \hbox{\tt name:} prefixes, and various font features can be
+      used as the first line in Figure~\ref{fig-jfdef}.
+\item The |jfm| key specifies the metric for the font. In
+      Figure~\ref{fig-jfdef}, both fonts will use a metric stored in a
+      Lua script named |jfm-ujis.lua|. This metric is the standard
+      metric in \LuaTeX-ja, and is based on JFMs used in the \emph{otf}
+      package~\cite{otf}.
+\item The \hbox{psft:} prefix can be used to specify name-only, non-embedded
+      fonts. When one displays a pdf with these fonts, actual fonts which
+      will be used for them depend on a pdf reader. 
+\end{itemize}
+The specification of a metric for \LuaTeX-ja is similar to that of a JFM
+(see \cite{ptexjp}); characters are grouped into several classes, the
+size information of characters are specified for each class, and
+glue/kern insertions are specified for each pair of classes. Although
+the author have not tried, it may be possible to develop a program that
+`converts' a JFM to a metric for \LuaTeX-ja.  \LuaTeX-ja offers three
+metrics by default; |jfm-ujis.lua|, |jfm-jis.lua| based on the
+\emph{jis} font metric, and |jfm-min.lua| based on old |min10.tfm|.
+
+ Note that |-kern| in features
+is important, because kerning information from a real font itself will
+clash with glue/kern information from the metric.
+
+\begin{figure}
+\begin{verbatim}
+\jfont\foo=file:ipam.ttf:jfm=ujis;script=latn;-kern;+jp04 at 12pt
+\jfont\bar=psft:Ryumin-Light:jfm=ujis at 10pt
+\end{verbatim}
+\caption{Typical declarations of Japanese fonts.}
+\label{fig-jfdef}
+\end{figure}
+
+\subsection{Insertion of glues/kerns for Japanese typesetting: timing}
+\label{ssec-jglue}
+
+As described in \cite{luatexref}, \LuaTeX's kerning and ligaturing
+processes are totally different from those of \TeX82.  \TeX82's process is
+done just when a (sequence of) character is appended to the current
+list. Thus we can interrupt this process by writing as
+|f{}irm|. However, \LuaTeX's process is \emph{node-based}, that is, the
+process will be done when a horizontal box or a paragraph is ended, so
+|f{}irm| and |firm| yield  same outputs under \LuaTeX.
+
+The situation for Japanese characters is more complicated.
+Glues (and kerns) which are needed for Japanese
+typesetting are divided into the following three categories:
+\begin{itemize}
+\item Glue (or kern) from the metric of Japanese fonts (\emph{JFM glue},
+      for short). 
+
+\item Default glue between a Japanese character and an alphabetic
+      character (\emph{xkanjiskip}, for short), usually 1/4 of
+      full-width (\emph{shibuaki}) with some stretch and shrink for
+      justifying each line.
+\item Default glue between two consecutive Japanese characters
+      (\emph{kanjiskip}, for short). The main reason of this glue is to
+      enable breaking lines almost everywhere in Japanese texts. In most
+      cases, its natural width is zero, and some stretch/shrink for
+      justifying each line.
+\end{itemize}
+In \pTeX, these three kinds of glues are treated differently. A JFM glue
+is inserted when a (sequence of) Japanese character is appended to the
+current list, same as the case of alphabetic characters in \TeX82. This
+means that one can interrupt the insertion process by saying |{}|.  A
+\emph{xkanjiskip} is inserted just before `hpack' or line-breaking of a
+paragraph; this timing is somewhat similar to that of \LuaTeX's kerning
+process. Finally, A \emph{kanjiskip} is not appeared as a node anywhere;
+only appears implicitly in calculation of the width of a horizontal box,
+that of breaking lines, and the actual output process to a DVI
+file. These specifications have made \pTeX's behavior very hard to
+understand.
+
+\LuaTeX-ja inserts glues in all three categories simultaneously inside
+|hpack_filter| and |pre_linebreak_filter| callbacks.  The reasons of
+this specification are to behave like alphabetic characters in \LuaTeX\
+(as described in the first paragraph in this subsection), and to clarify
+the specification for \LuaTeX-ja's process.
+
+\subsection{Insertion of glues/kerns for Japanese typesetting: specification}
+\label{ssec-jspec}
+
+\begin{table}
+\caption{Examples of differences between \pTeX\ and \LuaTeX-ja.}
+\label{tab-jfmglue}
+\begin{center}
+\begin{tabular}{llllllll}
+\toprule
+&\multicolumn{1}{c}{(1)}&\multicolumn{1}{c}{(2)}&\multicolumn{1}{c}{(3)}&\multicolumn{1}{c}{(4)}\\
+Input      &|あ】{}【〕\/〔|        &|い』\/a| &|う）\hbox{}（| &|え］\special{}［|\\\midrule
+\pTeX      &あ】\hbox{}【〕\hbox{}〔&い』\/a   &う）\hbox{}（   &え］\hbox{}［\\
+\LuaTeX-ja &あ】{}【〕\/〔          &い』\/a   &う）\hbox{}（   &え］\special{}［\\
+\bottomrule
+\end{tabular}
+\end{center}
+\end{table}
+
+\begin{figure}
+\begin{center}
+\fontsize{40}{40}\selectfont
+\imagfm{\jstrut あ}%
+\imagfm{\jstrut 】\inhibitglue}%
+\imagfm{\jstrut\kern.5\zw}%
+\imagfm{\jstrut\kern.5\zw}%
+\imagfm{\jstrut\inhibitglue【}%
+\imagfm{\jstrut 〕\inhibitglue}%
+\imagfm{\jstrut\kern.5\zw}%
+\imagfm{\jstrut\kern.5\zw}%
+\imagfm{\jstrut\inhibitglue〔}%
+\end{center}
+\caption{Detail of the output of \pTeX\ in the input~(1) in Table~\ref{tab-jfmglue}.}
+\label{fig-ptexjfm}
+\end{figure}
+
+Now we will take a look at the insertion process itself through four points.
+
+\begin{description}
+\item[Ignored nodes]
+As noted in the previous subsection, the insertion process in \pTeX\ can
+	   be interrupted by saying |{}| or anything else.\footnote{This
+	   is why some tricks like \texttt{ちょ\char`\{\char`\}っと} for
+	   \texttt{min10.tfm} and other `old' JFMs work.} This leads the
+	   second row in Table~\ref{tab-jfmglue}, or
+	   Figure~\ref{fig-ptexjfm}. Here `the process is interrupted'
+	   means that \pTeX\ does not think the letter `】\inhibitglue'
+	   is followed by `\inhibitglue【', hence two half-width glues
+	   are inserted between `】\inhibitglue' and `\inhibitglue【',
+	   where the left one is from `】\inhibitglue' and the right one
+	   is from `\inhibitglue【'.
+
+	   On the other hand, in \LuaTeX-ja, the process is done inside
+	   |hpack_filter| and |pre_linebreak_filter| callbacks. Hence,
+	   \emph{anything that does not make any node will be
+	   ignored}\ in \LuaTeX-ja, as shown in (1) in
+	   Table~\ref{tab-jfmglue}. \LuaTeX-ja also ignores any nodes
+	   which does not make any contribution to current horizontal
+	   list---\emph{ins\_node}, \emph{adjust\_node},
+	   \emph{mark\_node}, \emph{whatsit\_node} and
+	   \emph{penalty\_node}---, as shown in (4).
+
+
+By the way, around a \emph{glyph\_node} $p$ there may be some nodes
+	   attached to~$p$. These are an accent and kerns for
+	   moving it to the right place, and a kern from the italic
+	   correction\footnote{\TeX82 (and \LuaTeX) does not distinguish
+	   between explicit kern and a kern for italic correction. To
+	   distinguish them, an additional subtype for a kern is introduced
+	   in \pTeX. On the other hand, \LuaTeX-ja uses an additional attribute and
+	   redefines \texttt{\char`\\/} to set this attribute.} for $p$. It is natural that
+	   these attachments should be ignored inside the process. Hence
+	   \LuaTeX-ja takes this approach, as the latest version of
+	   \pTeX\ (version~p3.2). This explains (2) in the Table~\ref{tab-jfmglue}.
+
+Summerizing above, one should put an empty horizontal box |\hbox{}| to
+	   where he/she wants to interrupt the insertion process in
+	   \LuaTeX-ja as (3) in the Table~\ref{tab-jfmglue}.
+
+\item[Fonts with the same metric]
+Recall that \LuaTeX-ja separates `real' fonts and metrics, as in Subsection~\ref{ssec-sepmet}. 
+Consider the following input, where all Japanese fonts use same metric
+	   (in \LuaTeX-ja), and |\gt| selects \emph{gothic} family for
+	   the current Japanese font family:
+\begin{quote}
+\begin{verbatim}
+明朝）\gt （ゴシック
+\end{verbatim}
+\end{quote}
+If the above input is processed by \pTeX, because the insertion process is
+	   interrupt by |\gt|, the result looks like
+\begin{quote}
+\mc 明朝）\hbox{}\gt （ゴシック
+\end{quote}
+However this seems to be unnatural, since two Japanese fonts in the
+	   output use the same metric, i.e.,~the same
+	   typesetting rule.  Hence, we decided that Japanese fonts with
+	   the same metric are treated as one font in the insertion
+	   process of \LuaTeX-ja. Thus, the output from the above input
+	   in \LuaTeX-ja looks like:
+\begin{quote}
+\mc 明朝）\gt （ゴシック
+\end{quote}
+One might have the situation that this default behavior is not
+	   suitable. \LuaTeX-ja offers a way to handle this situation, but
+	   we leave it to the manual~\cite{man}.
+
+\item[Fonts with different metrics] 
+The case where two consecutive Japanese characters use different metrics and/or
+	   different size is similar. Consider the following input where
+	   the \emph{mincho} family and the \emph{gothic} family use
+	   different metrics:
+\begin{quote}
+\begin{verbatim}
+漢）\gt （漢）\large （大
+\end{verbatim}
+\end{quote}
+As the previous paragraph, this input yields the following, by \pTeX:
+\begin{quote}
+\mc 漢）\hbox{}\gt （漢）\hbox{}\large （大
+\end{quote}
+We had thought that amounts of spaces between parentheses in above output
+	   are too much. Hence we have changed the default behavior of
+	   \LuaTeX-ja, so that the amount of a glue between two Japanese
+	   characters with different metrics is the \emph{average} of a glue
+	   from the left character and that from the right
+	   character. For example, Figure~\ref{fig-diffmet} shows the
+	   output from above input. The width of glue indicated `(1)' is
+	   $(a/2 + a/2)/2 = 0.5a$, and the width of glue indicated `(2)'
+	   is $(a/2 + 1.2a/2)/2 = 0.55a$. This default behavior can be
+	   changed by \textsf{diffrentmet} parameter of \LuaTeX-ja.
+
+\begin{figure}
+\begin{center}
+\fontsize{40}{40}\selectfont
+\imagfm{\jstrut\smash{%
+  \vtop{\lineskiplimit=\maxdimen\lineskip2pt\halign{#\cr漢\cr
+    \small\vrule height .5ex depth .5ex\hrulefill\ \lower.5ex\hbox{$a$}\ 
+    \hrulefill\vrule height .5ex depth .5ex\cr}}}}%
+\imagfm{\jstrut ）\inhibitglue}%
+\hbox to .5\zw{\hss\normalsize (1)\hss}%
+\imagfm{\jstrut\inhibitglue\gt （}%
+\imagfm{\jstrut\gt 漢}%
+\imagfm{\jstrut\gt ）\inhibitglue}%
+\hbox to .55\zw{\hss\normalsize (2)\hss}%
+\imagfm{\fontsize{48}{48}\selectfont\jstrut\gt\inhibitglue （}%
+\imagfm{\fontsize{48}{48}\selectfont\jstrut\smash{%
+  \vtop{\lineskiplimit=\maxdimen\lineskip2pt\halign{#\cr\gt 大\cr
+    \small\vrule height .5ex depth .5ex\hrulefill\ \lower.5ex\hbox{$1.2a$}\ 
+    \hrulefill\vrule height .5ex depth .5ex\cr}}}}
+\end{center}
+\caption{Fonts with different metrics.}
+\label{fig-diffmet}
+\end{figure}
+
+\item[\emph{kanjiskip} and \emph{xkanjiskip}]
+In \pTeX, the value of \emph{xkanjiskip} is controlled by a skip named
+	   |\xkanjiskip|. A well-known defect of this implementation is
+	   that the value of \emph{xkanjiskip} is not connected with the
+	   size of the currnt Japanese font. It seems that |EXTRASPACE|,
+	   |EXTRASTRETCH|, |EXTRASHRINK| parameters in a JFM are
+	   reserved for specifying the default value of
+	   \emph{xkanjiskip} in a unit of the design size, but \pTeX\
+	   did not use these parameters, actually.
+
+Considering this situation of p\TeX, \LuaTeX-ja can use the value of
+	   \emph{xkanjiskip} that specified in a metric. If the value of
+	   \emph{xkanjiskip} on user side (this is the value of 
+	   \textsf{xkanjiskip} parameter of |\ltjsetparameter|) is
+	   |\maxdimen|, then \LuaTeX-ja use the specification from
+	   the current used metric as the actual value of
+	   \emph{xkanjiskip}. This description also applies for \emph{kanjiskip}.
+\end{description}
+
+\section{Distinction of characters}
+\label{sec:distinction_of_characters} Since \LuaTeX\ can handle Unicode
+characters natively, it is a major problem that how we distinguish
+Japanese characters and alphabetic characters. For example, the
+multiplication sign (U+00D7) exists both in ISO-8859-1 (hence in Latin-1
+Supplement in Unicode) and in the basic Japanese character set
+JIS~X~0208. It is not desirable that this character is always treated as
+an alphabetic character, because this symbol is often used in the sense
+of `negative' in Japan.
+
+\subsection{Character ranges}
+Before we describe the approach taken is \LuaTeX-ja, we review the
+approach taken by u\pTeX.  u\pTeX\ extends the |\kcatcode| primitive in
+\pTeX, to use this primitive for setting how a character is treated
+among alphabetic characters~(15), \emph{kanji}~(16), \emph{kana}~(17),
+\emph{kanji}, \emph{Hangul}~(17), or~\emph{other CJK characters}~(18).
+The assignment to |\kcatcode| can be done by a Unicode
+block.\footnote{There are some exceptions. For example, U+FF00--FFEF
+(Halfwidth and Fullwidth Forms) are divided into three blocks in recent
+u\pTeX.}
+
+\LuaTeX-ja adopted a different approach. There are many Unicode blocks
+	   in Basic Multilingual Plane which are not included in
+	   Japanese fonts, therefore it is inconvenient if we process by a Unicode
+	   block.  Furthermore, JIS~X~0208 are not just union of Unicode
+	   blocks; for example, the intersection of JIS~X~0208 and
+	   Latin-1 Supplement is shown in
+	   Table~\ref{tab-inter}. Considering these two points, to
+	   customize the range of Japanese characters in \LuaTeX-ja, one
+	   has to define ranges of character codes in his source in advance.
+
+
+\begin{table}
+\caption{Intersection of JIS~X~0208 and Latin-1 Supplement.}
+\label{tab-inter}
+\begin{center}
+\begin{tabular}{llll}
+\ltjjachar"A7 (U+00A7),&
+\ltjjachar"A8 (U+00A8),&
+\ltjjachar"B0 (U+00B0),&
+\ltjjachar"B1 (U+00B1),\\
+\ltjjachar"B4 (U+00B4),&
+\ltjjachar"B6 (U+00B6),&
+\ltjjachar"D7 (U+00D7),&
+\ltjjachar"F7 (U+00F7)
+\end{tabular}
+\end{center}
+\end{table}
+
+
+We note that \LuaTeX-ja offers two additional control sequences,
+      |\ltjjachar| and |\ltjalchar|. They are similar to |\char|
+      primitive, however |\ltjjachar| always yields a Japanese character, provided that
+      the argument is more than or equal to 128, and |\ltjalchar| always
+      yields an alphabetic character, regardless of the argument. 
+
+\subsection{Default setting of ranges}
+Patches for plain \TeX\ and \LaTeXe\ of \LuaTeX-ja predefine 8~character
+ranges, as shown in Table~\ref{tab-chrrng}.  Almost of these ranges are
+just the union of Unicode blocks, and determined from the Adobe-Japan1-6
+character collection~\cite{aj16}, and JIS~X~0208. Among these 8~ranges,
+the ranges~2, 3, 6, 7, and~8 are considered ranges of Japanese
+characters, and others are considered ranges of alphabetic
+characters.\footnote{Note that ranges 3~and~8 are considered ranges of
+alphabetic characters in this paper.}  We remark on ranges 2~and~8:
+\begin{description}
+\item[The range~2]
+JIS~X~0208 includes Greek letters and Cyrillic letters, however, these
+	   letters cannot be used for typesetting Greek or Russian, of
+	   course. Hence it is reasonable that Greek letters and
+	   Cyrillic consist another character range.
+\item[The range~8] 
+If one want to use 8-bit TFMs, such as T1 or TS1 encodings, he should
+	   mark this range~8 as a range of alphabetic characters by
+\begin{quote}
+|\ltjsetparameter{jacharrange={-8}}|
+\end{quote}
+This is because some 8-bit TFMs have a glyph in this range; for example,
+	   the character `\OE' is located at |"D7| in the T1 encoding. %"
+\end{description}
+
+
+\begin{table}
+\caption{Predefined ranges in \LuaTeX-ja.}
+\label{tab-chrrng}
+\begin{center}
+\begin{tabular}{@{\bf}rl}
+1&(Additional) Latin characters which are not belonged in the range~8.\\
+2&Greek and Cyrillic letters.\\
+3&Punctuations and miscellaneous symbols.\\
+4&Unicode blocks which does not intersect with Adobe-Japan1-6.\\
+5&Surrogates and supplementary private use Areas.\\
+6&Characters used in Japanese typesetting.\\
+7&Characters possibly used in CJK typesetting, but not in Japanese.\\
+8&Characters in Table~\ref{tab-inter}.
+\end{tabular}
+\end{center}
+\end{table}
+
+\subsection{Control sequences producing Unicode characters}
+\label{ssec-unichar}
+
+The \emph{fontspec} package\footnote{Preciously saying, it is the
+\emph{xunicode} package, originally a package for \XeTeX and
+automatically loaded by the \emph{fontspec} package.} offers various
+control sequences that produce Unicode characters.  However, these
+control sequences as it stands cannot work correctly with the default
+range setting of \LuaTeX-ja.  For example, |\textquotedblleft| is just
+an abbreviation of |\char"201C\relax|, and the character U+201C (LEFT %"
+DOUBLE QUOTATION MARK) is treated as an Japanese character, because it
+belongs to the range~3.  This problem is resolved by using |\ltjalchar|
+instead of the |\char| primitive.  It is included in an optional package
+named \texttt{luatexja-\penalty0fontspec.sty}.  Figure~\ref{fig-unitxt}
+shows several ways o typeset a character , both as a Japanese character
+and as as an alphabetic characters.
+
+\begin{figure}
+\begin{LTXexample}
+×, \char`×,   % depend on range setting 
+\ltjalchar`×, % alphabetic char
+\ltjjachar`×, % Japanese char
+\texttimes     % alph. char (by fontspec)
+\end{LTXexample}
+\caption{Control sequences producing a Unicode character.}
+\label{fig-unitxt}
+\end{figure}
+
+The situation looks similar in math formulas, but in fact it differs.
+Each control sequence that represents an ordinary symbol defined by the
+\emph{unicode-math} package is just synonym of a character. For example,
+the meaning of |\otimes| is just the character U+2297 (CIRCLED TIMES),
+which is included in the range~3.  However, it is difficult to define a
+control sequence like |\ltjalUmathchar| as a counterpart of
+|\Umathchar|, since an input like `|\sum^\ltjalUmathchar ...|' has to be
+permitted.
+
+However, we couldn't develop a satisfactory solution to this problem in
+time for this paper, due to a lack of time. We are just testing a
+solution below:
+\begin{itemize}
+\item \LuaTeX-ja has a list of character codes which will be always reated as
+      alphabetic characters in math mode. Considering 8-bit TFMs for
+      math symbols, this list includes natural numbers between |"80| and
+      |"FF| by default.
+\item Redefine internal commands defined in the \emph{unicode-math}
+      package so that
+codes of characters which are mentioned in the \emph{unicode-math}
+      package will be included in the list.
+\end{itemize}
+
+
+We would like to extend treatments described in this subsection to 8-bit
+font encodings, but we leave it to further development too.
+
+\section{Current status of development}
+\label{sec:current_status}
+At the moment, \LuaTeX-ja can be used under plain \TeX, and under
+\LaTeXe. Generally speaking, one only has to read |luatexja.sty|, by
+|\input| command or |\usepackage| (in~\LaTeXe), if you merely want to
+typeset Japanese characters.  We look more detail by parts. 
+
+\subsection{`Engine extension'}
+The lowest part of \LuaTeX-ja corresponds to the \pTeX\ extension as
+\emph{an engine extension of \TeX}. We, the project menbers, think that
+this part is almost done. There is one more feature of \LuaTeX-ja which
+we are going to explain:
+
+\begin{description}
+\item[Shifting baseline]
+In order to make a match between Japanese fonts and alphabetic fonts,
+	   sometimes shifting the baseline of alphabetic characters may
+	   be needed. \pTeX\ has a dimension |\ybaselineshift|, which
+	   corresponds to the amount of shifting down the baseline of alphabetic
+	   characters. This is useful for Japanese-based documents, but
+	   not for documents mainly in languages with alphabetic
+	   characters.
+
+Hence, \LuaTeX-ja extends \pTeX's |\ybaselineshift| to Japanese
+	   characters. Namely, \LuaTeX-ja offers two parameters,
+	   \textsf{yjabaselineshift} and \textsf{yalbaselineshift}, for the
+	   amount of shifting the baseline of Japanese characters and
+	   that of alphabetic characters, respectively. 
+\begin{figure}
+\begin{center}
+\fontsize{40}{40}\selectfont\fboxsep0mm
+\vrule width 0.9\textwidth height0.4pt depth0.4pt\kern-0.9\textwidth
+\hbox to 0.9\linewidth{%
+\hfil
+\raise-10pt\imagfm{\jstrut 漢}%
+\raise-10pt\imagfm{\jstrut 字}\hskip.25\zw%
+\imagfm{p}%
+\imagfm{h}%
+\hfil\hfil
+\imagfm{\jstrut 漢}%
+\imagfm{\jstrut 字}\hskip.25\zw%
+\raise-10pt\imagfm{p}%
+\raise-10pt\imagfm{h}%
+\hfil
+}
+\end{center}
+
+\caption{First example of shifting baseline.}
+\label{fig-bls}
+\end{figure}
+
+\begin{figure}
+\begin{center}
+\fontsize{30}{30}\selectfont\fboxsep0mm
+\vrule width 0.9\textwidth height0.4pt depth0.4pt\kern-0.9\textwidth
+\hbox to 0.9\linewidth{%
+\hfil
+\imagfm{a}%
+\imagfm{b}\hskip.25\zw%
+\imagfm{\jstrut 本}%
+\imagfm{\jstrut 文}\hskip.33333\zw%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut\inhibitglue （}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut 注}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut 釈}\hskip.1666667\zw%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont c}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont o}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont m}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont m}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont e}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont n}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont t}%
+\raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut ）\inhibitglue}%
+\hskip.33333\zw%
+\imagfm{\jstrut 本}%
+\imagfm{\jstrut 文}%
+\hfil
+}
+\end{center}
+
+\caption{Second example of shifting baseline.}
+\label{fig-small}
+\end{figure}
+
+An example output is shown in Figure~\ref{fig-bls}. The left half is the
+	   output when \textsf{yjabaselineshift} is positive, hence the
+	   baseline of Japanese characters is shifted down. On the other
+	   hand, the right half is the output when
+	   \textsf{yalbaselineshift} is positive, hence the baseline of
+	   alphabetic characters is shifted down. Figure~\ref{fig-small}
+	   shows an intresting use of these parameters.
+
+\end{description}
+Note that \LuaTeX-ja doesn't support vertical typesetting, \emph{tategaki}, for now. 
+
+\subsection{Patches for plain \TeX\ and \LaTeXe}
+\pTeX\ has a patch for plain \TeX, namely |ptex.tex|, that for \LaTeXe\
+macro (this patch and \LaTeXe\ consist \emph{p\LaTeXe}), and
+|kinsoku.tex| which includes the default setting of \emph{kinsoku
+shori}, the Japanese hyphenation.  We ported them to \LuaTeX-ja, except
+the codes related to vertical typesetting, because \LuaTeX-ja doesn't
+support vertical typesetting yet. We remark one point related to the
+porting:
+\begin{description}
+
+\item[Behavior of\/ {\tt\char92fontfamily\/}]
+The control sequence |\fontfamily| in p\LaTeXe\ changes the current alphabetic
+	   font family and/or the current Japanese font family,
+	   depending the argument. More concretely,
+	   |\fontfamily{|$\langle\hbox{\it arg\/}\rangle$|}| changes the
+	   current alphabetic font family to $\langle\hbox{\it
+	   arg\/}\rangle$, if and only if one of the following
+	   conditions are satisfied:
+\begin{itemize}
+\item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$ in
+      \emph{some} alphabetic encoding is already defined in the document.
+\item There exists an alphabetic encoding $\langle\hbox{\it
+      enc\/}\rangle$ already defined in the document such that a font
+      definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it
+      arg\/}\rangle$|.fd| (all lowercase) exists.
+\end{itemize}
+The same criterion is used for changing Japanese font family.
+
+To work this behavior well, a list of all (alphabetic) encodings defined
+	   already in the document is needed. However, since \LuaTeX-ja
+	   is loaded as a package, \LuaTeX-ja cannot have this list.
+	   Hence \LuaTeX-ja adopted a different approach, namely
+	   |\fontfamily{|$\langle\hbox{\it arg\/}\rangle$|}| changes the
+	   current alphabetic font family to $\langle\hbox{\it
+	   arg\/}\rangle$, if and only if:
+\begin{itemize}
+\item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$
+      in the current alphabetic encoding $\langle\hbox{\it
+      enc\/}\rangle$ is already defined in the document.
+\item A  font definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it
+      arg\/}\rangle$|.fd| (all lowercase) exists.
+\end{itemize}
+
+
+\end{description}
+
+
+
+\subsection{Classes for Japanese documents}
+To produce `high-quality' Japanese documents, we need not only that
+Japanese characters are correctly placed, but also class files for
+Japanese documents. Two major families of classes are widely used in Japan:
+\emph{jclasses} which is distributed with the official p\LaTeXe\ macros,
+and \emph{jsclasses}.  At the present, \LuaTeX-ja
+simply contains their counterparts: \emph{ltjclasses} and
+\emph{ltjsclasses}. However, the policy on classes is not determined
+now, and we hope to have another family of classes which are useful for
+commercial printing.  In the author's opinion, \emph{ltjclasses} is
+better to stay as an example of porting of class files for \pTeX\ to
+\LuaTeX-ja.
+
+\subsection{Patches for packages}
+Apart from patches for the \LaTeXe~kernel and classes for Japanese
+documents, we need to make patches for several packages. At the present,
+we considered the following packages, and made patches or porting for
+the former two packages.
+
+\begin{description}
+\item[The \emph{fontspec} package] The \emph{fontspec} package is built
+	   on NFSS2, hence control sequences offered by the
+	   \emph{fontspec} package, such as |\setmainfont|, are only
+	   effective for alphabetic fonts if \LuaTeX-ja is loaded.
+	   \texttt{luatexja-\penalty0fontspec.sty} (not automatically
+	   loaded) offers these counterparts for Japanese fonts, with
+	   additional `j' in the name of control sequences, such as
+	   |\setmainjfont|. As described in
+	   Subsection~\ref{ssec-unichar}, it also includes a patch for
+	   control sequences producing Unicode characters.
+
+\item[The \emph{otf} package]
+This package is widely used in \pTeX\ for typesetting characters which is
+not in JIS~X~0208, and for using more than one weight in \emph{mincho}
+and \emph{gothic} font families. Therefore \LuaTeX-ja supports features
+in the \emph{otf} package, by loading \texttt{luatexja-\penalty0otf.sty}
+	   manually. Note that characters by |\UTF{xxxx}| and
+	   |\CID{xxxx}| are not appended to the current list as a
+	   \emph{glyph\_node}, to avoid from callbacks by the
+	   \emph{luaotfload} package. We have another remark; |\CID|
+	   does not work with TrueType fonts, since |\CID| use the
+	   conversion table between CID and the glyph order of the
+	   current Japanese font.
+
+\item[The \emph{listings} package]
+It is known for users of \pTeX\ that there is a patch |jlisting.sty| for
+	   the \emph{listings} package, to use Japanese characters in
+	   the |lstlisting| environment. Generally speaking, it also can
+	   be used in \LuaTeX-ja. However, it seems to be that a
+	   Japanese character after a space does not recieve any process
+	   of the \emph{listings} package; this is inconvinient when we
+	   use the \emph{showexpl} package.
+
+There is another way to use characters above 256 with the
+	   \emph{listings} package (described in\cite{apl}). However,
+	   this method is not suitable for Japanese, since the number of
+	   Japanese characters is very large. We hope that the
+	   \emph{listings} package will be able to handle all characters above
+	   256 without any patch, in the future.
+
+
+\end{description}
+
+
+
+\section{Implementation}
+\label{sec:implementation}
+\subsection{Handling of Japanese fonts}
+In \pTeX, there are three slots for maintaining current fonts, namely
+|\font| for alphabetic fonts, |\jfont| for Japanese fonts (in horizontal
+direction) and |\tfont| for Japanese fonts (in vertical direction). With
+these slots, we can manage the current font for alphabetic characters
+and that for Japanese characters separately in \pTeX.  However, \LuaTeX\
+has only one slot for maintaining the current font, as \TeX82.  This
+situation leads a problem: how can we maintain the `current Japanese
+font'?
+
+There are three approaches for this problem. One approach is to make a
+mapping table from alphabetic fonts to corresponding Japanese fonts
+(here we don't assume that NFSS2 is available).  Another approach is
+that we always use composite fonts with alphabetic fonts and Japanese
+fonts. The third approach is that the information of the current
+Japanese font is stored in an attribute. We adopted the third approach,
+since \LuaTeX-ja is much affected by \pTeX\ as we noted in
+Subsection~\ref{ssec-pol}.
+
+As in Figure~\ref{fig-jfdef}, \LuaTeX-ja uses |\jfont| for defining
+Japanese fonts, as \pTeX.  However, because the information of the current
+Japanese font is stored into an attribute, control sequences defined by
+|\jfont| (e.g.,~|\foo| and |\bar| in Figure~\ref{fig-jfdef}) is
+not representing a font by the means of \TeX82. In other words, each of
+these control sequences is just an assignment to an attribute, therefore
+they cannot be an argument of |\the|, |\fontname|, nor |\textfont|.
+
+
+Callbacks by the \emph{luaotfload} package, e.g.,~replacement of glyphs
+according to OpenType font features, are performed just after `Examination of
+stack level' (see Subsections
+\ref{ssec-over}~and~\ref{ssec-stack}). Also note that calculation of
+character classes for each Japanese character is done \emph{after} the
+these callbacks for now. 
+
+\subsection{Stack management}
+\label{ssec-stack}
+
+As we noted in Subsection~\ref{ssec-csname}, parameters that the values
+at the end of a horizontal box or that of a paragraph are valid in
+whole box or paragraph, such as \emph{kanjiskip}, cannot be implemented
+by internal integers or registers of other types in \TeX. We explain it
+in this subsection.
+
+\begin{figure}
+\begin{lstlisting}
+void package(int c)
+{
+    ...
+    d = box_max_depth;
+    unsave();
+    save_ptr -= 4;
+    if (cur_list.mode_field == -hmode) {
+        cur_box = filtered_hpack(cur_list.head_field,
+                                 cur_list.tail_field, saved_value(1),
+                                 saved_level(1), grp, saved_level(2));
+        subtype(cur_box) = HLIST_SUBTYPE_HBOX;
+    } else {
+\end{lstlisting}
+\caption{An extract of a CWEB-source \texttt{tex/packaging.w} of \LuaTeX.}
+\label{fig-ltsrc}
+\end{figure}
+
+Figure~\ref{fig-ltsrc} is an extract of a CWEB-source
+\texttt{tex/packaging.w} of \LuaTeX\ (SVN revision 4358). This function
+is called just when an explicit |\hbox{...}| or |\vbox{...}| is ended, and
+the function |filtered_hpack()| is where the |hpack_filter| and then the
+actual `hpack' process are performed. Notice that the |unsave()|
+function is called before |filtered_hpack()|. This is the problem;
+because of |unsave()|, we can retrive only the values of registers
+\emph{outside} the box, even in the |hpack_filter| callback.
+
+To cope with this problem, \LuaTeX-ja has its own stack system, based on
+Lua codes in \cite{stack-mail}. Furthermore, \emph{whatsit} nodes whose
+\emph{user\_id} is 30112 (\emph{stack\_node}, for short) will be
+appended to the current horizontal list each time the current stack
+level is incremented, and their values are the values of
+|\currentgrouplevel| at that time. In the beginning of the |hpack_filter|
+callback, the list in question is traversed to determine whether the
+stack level at the end of the list and that outside the box coincides.
+
+Let $x$ be the value of |\currentgrouplevel|, and $y$ be the current
+stack level, both inside the |hpack_filter| callback, i.e.,~outside a
+horizontal box. Consider a list which represents the content of the box,
+then we have:
+\begin{itemize}
+\item A \emph{stack\_node} whose value is $x+1$ (because all materials
+      in the box are included in a group |\hbox{...}|, the value of
+      |\currentgrouplevel| inside the box is at least $x+1$) in the list
+      corresponds to an assignment related to the stack system in just
+      top-level of the list, like
+\begin{quote}
+\begin{verbatim}
+\hbox{...(assignment)...}
+\end{verbatim}
+\end{quote}
+In this case, the current stack level is incremented to $y+1$ after the assignment.
+\item A \emph{stack\_node} whose value is more than  $x+1$ in the list corresponds
+to an assignment inside another group contained in the box. For example,
+      the following input creates
+a \emph{stack\_node} whose value is $x+3=(x+1)+2$:
+\begin{quote}
+\begin{verbatim}
+\hbox{...{...{...(assignment)}...}...}
+\end{verbatim}
+\end{quote}
+\end{itemize}
+Thus, we can conclude that the stack level at the end of the list is
+$y+1$, if and only if there is a \emph{stack\_node} whose value is
+$x+1$. Otherwise, the stack level is just $y$.
+
+\subsection{Adjustment of the position of Japanese characters}
+\label{ssec-width}
+
+The size of a glyph specified in a metric and that of a real font
+usually differ. For example, the letter `\inhibitglue【' is half-width
+in |jfm-ujis.lua| or |jis.tfm|, while this letter is full-width like `【'
+in most TrueType fonts used in Japanese typesetting, such as
+IPA~Mincho. Hence the adjustment of position of such glyphs is
+needed. In the context of \pTeX, this process was performed using virtual fonts.
+
+On the other hand, Lua\TeX-ja does the adjustment by encapsuling a glyph
+into a horizontal box. There are two main reasons why we adopted this
+method; one is that we feared Lua codes for coexisting with callbacks by
+the |luaotfload| package would be large if we use virtual fonts, and the
+other is to cope with shifting of the baseline of characters at the
+same time. 
+
+\begin{figure}
+\begin{center}\unitlength=9pt\small
+\begin{picture}(15,12)(-1,-3)
+
+\color{grayx}% real glyph
+\put(-1,-1.5){\vrule width 6\unitlength height 7\unitlength depth 2.5\unitlength}
+
+\color{black}% real glyph :step1
+\thicklines
+\put(-1,-1.5){\line(0,1){7}\line(0,-1){2.5}}
+\put(5,-1.5){\line(0,1){7}\line(0,-1){2.5}}
+\put(-1,5.5){\line(1,0){6}}
+\put(-1,-4){\line(1,0){6}}
+\put(-1,0){\makebox(0,0)[r]{\strut$R$\,}}
+
+\thicklines
+\put(0,0){\vector(0,1){9}\line(0,-1){3}\vector(1,0){12}}
+\put(12,9){\makebox(0,0)[rt]{\strut$M$\,}}
+\put(12,0){\line(0,1){9}\vector(0,-1){3}}
+\put(0,9){\line(1,0){12}}
+\put(0,-3){\line(1,0){12}}
+\put(0.2,4.5){\makebox(0,0)[l]{\texttt{height}}}
+\put(12.2,-1.5){\makebox(0,0)[l]{\texttt{depth}}}
+\put(6,0.2){\makebox(0,0)[b]{\texttt{width}}}
+
+\thicklines
+\put(3,0){\line(0,1){7}\line(0,-1){2.5}\line(1,0){6}}
+\put(9,0){\line(0,1){7}\line(0,-1){2.5}}
+\put(3,7){\line(1,0){6}}
+\put(3,-2.5){\line(1,0){6}}
+\newsavebox{\eqdist}
+\savebox{\eqdist}(0,0)[c]{%
+  \thinlines
+  \put(-0.08,0.2){\line(0,-1){0.4}}%
+  \put(0.08,0.2){\line(0,-1){0.4}}}
+\put(1.5,0){\usebox{\eqdist}}
+\put(10.5,0){\usebox{\eqdist}}
+
+\thicklines
+\put(3,-1.5){\vector(-1,0){4}}
+\put(1,-1.7){\makebox(0,0)[t]{\texttt{left}}}
+\put(3,0){\vector(0,-1){1.5}}
+\put(3.2,-0.75){\makebox(0,0)[l]{\texttt{down}}}
+\end{picture} 
+\end{center}
+\caption{The position of the `real' glyph.}
+\label{fig-pos}
+\end{figure}
+
+Figure~\ref{fig-pos} shows the adjustment process. A large square $M$ is
+the imaginary body specified in the metric, and a vertical
+rectangle is the imaginary body of a real glyph. First, the real glyph
+is aligned with respect to the width of $M$. In the figure, the real
+glyph is aligned `middle'; this setting is useful for the full-width
+middle dot `・'. We have other settings, `left' and `right'.
+After that, it is shifted according to the value of |left| and |down|,
+which are specified in the metric, too. The final position of the real glyph
+is shown by the gray rectangle~$R$. If the amount of shifting the baseline is
+not zero, $M$ (and hence the real glyph) is shifted by that amount.
+
+We would like to remark briefly on the vertical position of a real
+glyph.  A JFM (or a metric used in \LuaTeX-ja) and a real font used for
+it may have different height or depth.  In that case, it may look better
+if the real glyph is shifted vertically to match the height-depth ratio
+specified in the metric, while any vertical adjustment except the
+adjustment by the |down| value does not performed in the present
+implementation of \LuaTeX-ja . This situation is carefully studied by
+Otobe~\cite{min10}. Here the policy on this problem is not determined
+now, however we would like to offer several solutions in future
+development.
+
+\section{Conclusion}
+We have discussed about our \LuaTeX-ja package, which is much affected
+by \pTeX. For now, it can be used for experimental use, however there
+are much refinements which are needed for regular use. The author hopes
+that this paper and \LuaTeX-ja project contribute the typesetting Japanese,
+and possibly other Asian languages, under \LuaTeX.
+
+\section*{Acknowledgements}
+The author would like to thank Ken Nakano and Hideaki Togashi for their
+development of ASCII \pTeX.  The author is very grateful to Haruhiko
+Okumura for his leadership in the Japanese \TeX\ community. The author
+is also very grateful to members of \LuaTeX-ja project team for their
+valuable cooperation in development.
+
+%%% The style of the bibiliogrphy is `amsplain'.
+\providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}
+\providecommand{\href}[2]{#2}
+\begin{thebibliography}{99}
+
+\bibitem{aj16}
+Adobe Systems Incorporated, \emph{Adobe-Japan1-6 Character Collection
+	for CID-Keyed Fonts}, Technical Note~\#5078, 2004.
+\url{http://partners.adobe.com/public/developer/en/font/5078.Adobe-Japan1-6.pdf}
+
+\bibitem{ptex}
+ASCII MEDIA WORKS，アスキー日本語\TeX\ (\pTeX)．\url{http://ascii.asciimw.jp/pb/ptex/}
+
+\bibitem{apl}
+John Baker, \emph{Typesetting UTF8 APL code with the \LaTeX\ lstlisting package}.
+\url{http://bakerjd99.wordpress.com/2011/08/15/}
+
+\bibitem{omega}
+Jin-Hwan~Cho and Haruhiko Okumura, \emph{Typesetting CJK Languages with Omega},
+\TeX, XML, and Digital Typography, Lecture Notes in Computer Science, vol.~3130,
+Springer, 2004, 139--148.
+
+\bibitem{joylua}
+Yannis Haralambous. \emph{The Joy of \LuaTeX}. \url{http://luatex.bluwiki.com/}
+
+\bibitem{jisx4051}
+Japanese Industrial Standards Committee. \emph{JIS~X~4051: Formatting
+	rules for Japanese documents}, 1993, 1995, 2004.
+
+\bibitem{eptex}
+北川弘典，$\varepsilon$-\pTeX についてのwiki．
+\url{http://sourceforge.jp/projects/eptex/wiki/FrontPage}
+
+\bibitem{luaums}
+北川弘典，\LuaTeX で日本語．
+\url{http://oku.edu.mie-u.ac.jp/tex/mod/forum/discuss.php?d=378}
+
+\bibitem{luatexref}
+\LuaTeX\ development team, \emph{The \LuaTeX\ reference}. 
+\url{http://www.luatex.org/svn/trunk/manual/luatexref-t.pdf} (snapshot of SVN trunk)
+
+\bibitem{man}
+\LuaTeX-ja project team, \emph{The \LuaTeX-ja package}. 
+Not completed for now. Available at |doc/man-en.pdf| (in English) or
+	|doc/man-ja.pdf| (in Japanese)
+in the Git repository.
+
+\bibitem{luajp-test}
+香田温人，\LuaTeX と日本語．
+\url{http://www1.pm.tokushima-u.ac.jp/~kohda/tex/luatex-old.html}
+
+\bibitem{luajalayout}
+前田一貴，luajalayout パッケージ---Lua\LaTeX によ
+	る日本語組版---．
+\url{http://www-is.amp.i.kyoto-u.ac.jp/lab/kmaeda/lualatex/luajalayout/}
+
+\bibitem{jsclasses}
+奥村晴彦，p\LaTeXe 新ドキュメントクラス．
+\url{http://oku.edu.mie-u.ac.jp/~okumura/jsclasses/}
+
+\bibitem{ptexjp}
+Haruhiko Okumura, \emph{\pTeX\ and Japanese Typesetting},
+	The Asian Journal of \TeX\ \textbf{2}~(2008), 43--51.
+
+\bibitem{min10}
+乙部厳己，min10フォントについて．
+\url{http://argent.shinshu-u.ac.jp/~otobe/tex/files/min10.pdf}
+
+\bibitem{otf}
+齋藤修三郎，Open Type Font用VF．
+\url{http://psitau.kitunebi.com/otf.html}
+
+\bibitem{stack-mail}
+Jonathan Sauer, \emph{[Dev-luatex] tex.currentgrouplevel}. 
+\url{http://www.ntg.nl/pipermail/dev-luatex/2008-August/001765.html}
+
+\bibitem{uptex}
+Takuji Tanaka, \emph{u\pTeX, up\LaTeX---unicode version of \pTeX, p\LaTeX}.
+\url{http://homepage3.nifty.com/ttk/comp/tex/uptex_en.html}
+
+\bibitem{ptexenc}
+Nobuyuki Tsuchimura and Yusuke Kuroki, \emph{Development of Japanese \TeX\ Environment},
+	The Asian Journal of \TeX\ \textbf{2}~(2008), 53--62.
+
+\bibitem{w3c}
+W3C Working Group, \emph{Requirements for Japanese Text Layout}. 
+\url{http://www.w3.org/TR/jlreq/}
+\end{thebibliography}
+
+\end{document}