[latex3-commits] [latex2e-public] r1316 - rough first draft of some words about TU encoding

[noreply at latex-project.org]

Author: carlisle
Date: 2016-12-31 14:37:39 +0100 (Sat, 31 Dec 2016)
New Revision: 1316

Modified:
   trunk/doc/ltnews26.tex
Log:
rough first draft of some words about TU encoding

Modified: trunk/doc/ltnews26.tex
===================================================================
--- trunk/doc/ltnews26.tex	2016-12-30 18:27:36 UTC (rev 1315)
+++ trunk/doc/ltnews26.tex	2016-12-31 13:37:39 UTC (rev 1316)
@@ -1,77 +1,113 @@
-% \iffalse meta-comment
-%
-% Copyright 2016
-% The LaTeX3 Project and any individual authors listed elsewhere
-% in this file.
-%
-% This file is part of the LaTeX base system.
-% -------------------------------------------
-%
-% It may be distributed and/or modified under the
-% conditions of the LaTeX Project Public License, either version 1.3c
-% of this license or (at your option) any later version.
-% The latest version of this license is in
-%    http://www.latex-project.org/lppl.txt
-% and version 1.3c or later is part of all distributions of LaTeX
-% version 2005/12/01 or later.
-%
-% This file has the LPPL maintenance status "maintained".
-%
-% The list of all files belonging to the LaTeX base distribution is
-% given in the file `manifest.txt'. See also `legal.txt' for additional
-% information.
-%
-% The list of derived (unpacked) files belonging to the distribution
-% and covered by LPPL is defined by the unpacking scripts (with
-% extension .ins) which are part of the distribution.
-%
-% \fi
-% Filename: ltnews26.tex
-%
-% This is issue 26 of LaTeX News.
-
-\documentclass{ltnews}
-\usepackage[T1]{fontenc}
-
-\usepackage{lmodern,url,hologo}
-
-
-\publicationmonth{December}
-\publicationyear{2016}
-
-\publicationissue{26}
-
-\begin{document}
-
-\maketitle
-
-\section{\eTeX{}}
-
-In \LaTeX{} News~16 (December 2003) the team announced
-\begin{quotation}
-We expect that within the next two years, releases of \LaTeX{} will
-change modestly in order to run best under an extended \TeX{} engine
-that contains the \eTeX{} primitives, e.g., \eTeX{} or pdf\TeX{}.
-\end{quotation}
-and also said
-\begin{quotation}
-Although the current release does not \emph{require} \eTeX{} features, we
-certainly recommend using an extended \TeX{}, especially if you need to debug
-macros.
-\end{quotation}
-
-For many years the team have worked on the basis that users will have \eTeX{}
-available but had not revisited the above statements formally. As of the
-January 2017 release of \LaTeXe{}, \eTeX{} is \emph{required} to build the
-format, and attempting to build a format without the extensions will fail.
-
-Practically, modern \TeX{} distributions provide the extensions in all engines
-other than the ``pure'' Knuth \texttt{tex}, and indeed parts of the
-format-building process already require \eTeX{}, most notably some of the UTF-8
-hyphenation patterns. As such, there should be no noticeable affect on users of
-this change.
-
-The team expect to make wider use of \eTeX{} within the kernel in future;
-details will be announced where they impact on end users in a visible way.
-
+% \iffalse meta-comment
+%
+% Copyright 2016
+% The LaTeX3 Project and any individual authors listed elsewhere
+% in this file.
+%
+% This file is part of the LaTeX base system.
+% -------------------------------------------
+%
+% It may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3c
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%    http://www.latex-project.org/lppl.txt
+% and version 1.3c or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This file has the LPPL maintenance status "maintained".
+%
+% The list of all files belonging to the LaTeX base distribution is
+% given in the file `manifest.txt'. See also `legal.txt' for additional
+% information.
+%
+% The list of derived (unpacked) files belonging to the distribution
+% and covered by LPPL is defined by the unpacking scripts (with
+% extension .ins) which are part of the distribution.
+%
+% \fi
+% Filename: ltnews26.tex
+%
+% This is issue 26 of LaTeX News.
+
+\documentclass{ltnews}
+\usepackage[T1]{fontenc}
+
+\usepackage{lmodern,url,hologo}
+
+
+\publicationmonth{December}
+\publicationyear{2016}
+
+\publicationissue{26}
+
+\begin{document}
+
+\maketitle
+
+\section{\eTeX{}}
+
+In \LaTeX{} News~16 (December 2003) the team announced
+\begin{quotation}
+We expect that within the next two years, releases of \LaTeX{} will
+change modestly in order to run best under an extended \TeX{} engine
+that contains the \eTeX{} primitives, e.g., \eTeX{} or pdf\TeX{}.
+\end{quotation}
+and also said
+\begin{quotation}
+Although the current release does not \emph{require} \eTeX{} features, we
+certainly recommend using an extended \TeX{}, especially if you need to debug
+macros.
+\end{quotation}
+
+For many years the team have worked on the basis that users will have \eTeX{}
+available but had not revisited the above statements formally. As of the
+January 2017 release of \LaTeXe{}, \eTeX{} is \emph{required} to build the
+format, and attempting to build a format without the extensions will fail.
+
+Practically, modern \TeX{} distributions provide the extensions in all engines
+other than the ``pure'' Knuth \texttt{tex}, and indeed parts of the
+format-building process already require \eTeX{}, most notably some of the UTF-8
+hyphenation patterns. As such, there should be no noticeable affect on users of
+this change.
+
+The team expect to make wider use of \eTeX{} within the kernel in future;
+details will be announced where they impact on end users in a visible way.
+
+\section{Default Encodings in \hologo{XeLaTeX} and \hologo{LuaLaTeX}}
+The default encoding in \LaTeX\ has always been the original
+127-character encoding ``OT1''.  For Unicode based \TeX\ engines, this
+is not really suitable, and is especially problematic with
+\hologo{XeLaTeX} as in the major distributions this is built with
+Unicode base hyphenation patterns in the format.  In practice this has
+not been a major problem as documents use the contributed
+\textsf{fontspec} package in order to switch to a
+Unicode encoded font..
+
+In this release we are adding ``\textbf{TU}'' as a new supported
+encoding in addition to the previously supported encodings such as OT1
+and T1. This denotes a Unicode based font encoding. It is essentially
+the same as the TU encoding that has been on trial with the
+experimental \texttt{tuenc} option to \textsf{fontspec} for the past
+year.
+
+The \hologo{XeLaTeX} and \hologo{LuaLaTeX} formats will now default
+to \texttt{TU} encoding and \texttt{lmr} (Latin Modern) family. In the
+case of \hologo{LuaLaTeX} the contributed \textsf{luaotfload} Lua
+module will be loaded at the start of each run to enable the loading
+of OpenType fonts.
+
+The \textsf{fontspec} package is being adjusted in a companion release
+to recognise the new encoding defaullt arrangements.
+
+Note that in practice no font supports the full Unicode range, and so
+TU encoded fonts, unlike fonts specified for T1, may be expected to
+be incomplete in various ways. In the current release the format has 
+made some basic assumptions for (for example) default handling of
+accent commands. The \textsf{fontspec} package has more control over
+finer details of the font loadeding and control over OpenType
+features. More facilities may be added as needed. Initially they will
+be added in \textsf{fontspec} with some aspects possibly being moved
+to the base format at a later date.
+
 \end{document}
\ No newline at end of file