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diff --git a/Master/texmf-dist/doc/latex/base/ltnews27.tex b/Master/texmf-dist/doc/latex/base/ltnews27.tex new file mode 100644 index 00000000000..37b2fcf89e4 --- /dev/null +++ b/Master/texmf-dist/doc/latex/base/ltnews27.tex @@ -0,0 +1,135 @@ +% \iffalse meta-comment +% +% Copyright (C) 2017-2019 +% 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 2008 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: ltnews27.tex +% +% This is issue 27 of LaTeX News. + +\documentclass{ltnews} +\usepackage[T1]{fontenc} + +\usepackage{lmodern,url,hologo} + +\publicationmonth{April} +\publicationyear{2017} + +\publicationissue{27} + +\begin{document} + +\maketitle +\tableofcontents + +\setlength\rightskip{0pt plus 3em} + +\section{ISO 8601 Date format} +Since before the first releases of \LaTeXe, \LaTeX\ has used a date +format in the form \textsc{yyyy/mm/dd}. This has many advantages over more +conventional formats, as it is easy to sort and avoids the unfortunate +ambiguity between different communities as to whether 01/02/2017 is the +1st of February or 2nd of January. + +However there is another date format, formalised by the +International Standard ISO~8601. The basic format defined by this +standard is functionally equivalent to the \LaTeX\ format, but using +\texttt{-} rather than \texttt{/}. This date format is now supported +in many Operating Systems and applications +(for example the \verb|date --iso-8601| command in Linux and similar systems). + +From this release, \LaTeX\ will accept ISO format date strings in the +date argument of \verb|\ProvidesPackage|, \verb|\usepackage|, etc. +Currently we recommend that you do not use this format in any packages +that need to work with older \LaTeX\ releases; +the \textsf{latexrelease} package may be used with older releases to + add this functionality. This change is handled in a special way by + \textsf{latexrelease}: The package always adds support for ISO dates +whatever format date is requested; this is required so that the +necessary date comparisons may be made. + +The new functionality can be seen in the startup banner which +advertises \texttt{LaTeX2e <2017-04-15>}. + +\section{Further TU encoding improvements} +The 2017/01/01 release saw the introduction of the new TU encoding for +specifying Unicode fonts with \hologo{LuaTeX} and +\hologo{XeTeX}. There were a number of small corrections and additions +in the patch releases updating 2017/01/01, and a further addition in +this release, notably extended support for the dot-under accent, +\verb|\d|. + + +\section{Disabling hyphenation} +The existing \LaTeX\ code for \verb|\verb| and \verb|verbatim| had some +issues when used with fonts that were not loaded with hyphenation +disabled via setting \verb|\hyphenchar| to $-1$. In this release these +verbatim environments use a \verb|\language| setting, +\verb|\l@nohyphenation|, that has no hyphenation patterns associated. + +The format ensures that a language has been allocated with this name. +For most users this will in fact be no change as the standard +\textsf{babel} language has for a long time allocated a language with +this name. + +In order that page breaks in \texttt{verbatim} do not influence the +language used in the page head and foot, the format now normalises the +language used in the output routine to a default language as described +below. + +\section{Discretionary hyphenation} +The \LaTeX\ definition of \verb|\-| has been adjusted so that it will +insert the current font's \verb|\hyphenchar|, as would the +\TeX\ primitive. A comment in \textsf{source2e} has given +this new definition since the first releases of \LaTeXe, and in this +release we finally acted upon this comment. Previously \verb|\-| +always inserted a \texttt{-} at a break point even if a different +character would be used for automatic hyphenation with the current font. + +\section{Default document language} + +A new integer parameter \verb|\document@default@language| is +introduced; this is initialised to $-1$ but is set at +\verb|\begin{document}| to the language in force at that time if it + has not been set by preamble code. This is very similar to the + handling of the default color, and is used in a similar way to + normalise the settings for page head and foot as described above. +Users should not normally need to set this explicitly but it is expected that +language packages such as \textsf{babel} may set this if the default +behaviour is not suitable. + +\section{Line spacing in parboxes} +Inside a \verb|\parbox| +\LaTeX\ normalises the baseline spacing. However it has not +previously reset \verb|\lineskiplimit|. This meant that +lines of a paragraph that have ascenders or descenders could be set +with \emph{closer} line spacing than lines without. This can easily +happen if you use a \verb|\parbox| in an AMS alignment, as they use a +relatively large value of \verb|\lineskiplimit|. +As usual, the \textsf{latexrelease} package may be used to +force the older behavior. + +\end{document} |