[latex3-commits] [git/LaTeX3-latex3-latex2e] develop: Flesh out details on primitive requirements (904a3859)

[Joseph Wright]

Repository : https://github.com/latex3/latex2e
On branch  : develop
Link       : https://github.com/latex3/latex2e/commit/904a38591c527b37ccf3c5695ec5a4096dbc9a56

>---------------------------------------------------------------

commit 904a38591c527b37ccf3c5695ec5a4096dbc9a56
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Thu Jan 9 18:27:00 2020 +0000

    Flesh out details on primitive requirements


>---------------------------------------------------------------

904a38591c527b37ccf3c5695ec5a4096dbc9a56
 base/doc/ltnews31.tex | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/base/doc/ltnews31.tex b/base/doc/ltnews31.tex
index be63ecc7..f703d552 100644
--- a/base/doc/ltnews31.tex
+++ b/base/doc/ltnews31.tex
@@ -581,7 +581,7 @@ A number of the additional primitives are needed to support new or improved
 functionality in \LaTeX{}. This is seen for example in improved UTF-8 handling,
 which uses \cs{ifincsname}. The following primitive functionality (which in
 \LuaTeX{} may be achieved using Lua code) will therefore be \emph{required} by
-the \LaTeX{} kernel after [INSERT DATE HERE]:
+the \LaTeX{} kernel from the start of 2021:
 \begingroup\setlength\columnsep{0pt}
 \begin{multicols}{2}
 \begin{itemize}
@@ -611,10 +611,16 @@ the \LaTeX{} kernel after [INSERT DATE HERE]:
 \end{multicols}
 \endgroup
 For ease of reference, these primitives will be referred to as the
-`\pdfTeX{} utilities'.
-
-Engines which are fully Unicode-capable must all provide the following
-primitives
+`\pdfTeX{} utilities'. With the exception of \cs{expanded}, these have been
+present in \pdfTeX{} since the release of version 1.40.0 in 2007; \cs{expanded}
+was added for \TeX{}~Live 2019. Similarly, the full set of utility primitives
+have been available in \XeTeX{} from the 2019 \TeX{}~Live release, and have
+always been available in \LuaTeX{} (some by Lua emulation). p\TeX{} and
+up\TeX{} gained all of the above bar \cs{ifincsname} for \TeX{}~Live
+2019, and will have that primitive from the 2020 release.
+
+At the same time, engines which are fully Unicode-capable must all provide
+the following primitives
 \begingroup\setlength\columnsep{0pt}
 \begin{multicols}{2}
 \begin{itemize}
@@ -625,7 +631,8 @@ primitives
 \end{multicols}
 \endgroup
 Note that it has become standard practice to check for Unicode-aware engines
-with the existence of the \cs{Umathcode} primitive.
+with the existence of the \cs{Umathcode} primitive. As such, this is already
+a requirement: engines lacking these primitives cannot access Unicode features.
 
 \begin{thebibliography}{9}