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-rw-r--r--macros/latex-dev/base/ltfssini.dtx940
1 files changed, 882 insertions, 58 deletions
diff --git a/macros/latex-dev/base/ltfssini.dtx b/macros/latex-dev/base/ltfssini.dtx
index b073a5cc37..e948aa4809 100644
--- a/macros/latex-dev/base/ltfssini.dtx
+++ b/macros/latex-dev/base/ltfssini.dtx
@@ -1,6 +1,6 @@
% \iffalse meta-comment
%
-% Copyright (C) 1993-2019
+% Copyright (C) 1993-2020
% The LaTeX3 Project and any individual authors listed elsewhere
% in this file.
%
@@ -36,7 +36,7 @@
%
%
\ProvidesFile{ltfssini.dtx}
- [2019/08/27 v3.1d LaTeX Kernel (NFSS Initialisation)]
+ [2020/01/11 v3.1f LaTeX Kernel (NFSS Initialisation)]
% \iffalse
\documentclass{ltxdoc}
\begin{document}
@@ -157,26 +157,28 @@
% Now we define the standard font change commands.
% We don't allow the use of |\rmfamily| etc.\ in math mode.
%
+% (Actually most are now defined further down in the file.)
+%
% First the changes to another \emph{family}:
% \begin{macrocode}
-\DeclareRobustCommand\rmfamily
- {\not@math@alphabet\rmfamily\mathrm
- \fontfamily\rmdefault\selectfont}
-\DeclareRobustCommand\sffamily
- {\not@math@alphabet\sffamily\mathsf
- \fontfamily\sfdefault\selectfont}
-\DeclareRobustCommand\ttfamily
- {\not@math@alphabet\ttfamily\mathtt
- \fontfamily\ttdefault\selectfont}
+%\DeclareRobustCommand\rmfamily
+% {\not@math@alphabet\rmfamily\mathrm
+% \fontfamily\rmdefault\selectfont}
+%\DeclareRobustCommand\sffamily
+% {\not@math@alphabet\sffamily\mathsf
+% \fontfamily\sfdefault\selectfont}
+%\DeclareRobustCommand\ttfamily
+% {\not@math@alphabet\ttfamily\mathtt
+% \fontfamily\ttdefault\selectfont}
% \end{macrocode}
% Then the commands changing the \emph{series}:
% \begin{macrocode}
-\DeclareRobustCommand\bfseries
- {\not@math@alphabet\bfseries\mathbf
- \fontseries\bfdefault\selectfont}
-\DeclareRobustCommand\mdseries
- {\not@math@alphabet\mdseries\relax
- \fontseries\mddefault\selectfont}
+%\DeclareRobustCommand\bfseries
+% {\not@math@alphabet\bfseries\mathbf
+% \fontseries\bfdefault\selectfont}
+%\DeclareRobustCommand\mdseries
+% {\not@math@alphabet\mdseries\relax
+% \fontseries\mddefault\selectfont}
\DeclareRobustCommand\upshape
{\not@math@alphabet\upshape\relax
\fontshape\updefault\selectfont}
@@ -196,29 +198,873 @@
%
%
%
+%
+% \section{Custom series settings for main document families}
+%
+% This section was introduced 2020/02/02 and for now we support a
+% full rollback (may need splitting later).
+% \changes{v3.1e}{2019/12/17}{Provide custom series settings a la mweights}
+% \begin{macrocode}
+%</2ekernel>
+%<*2ekernel|latexrelease>
+%<latexrelease>\IncludeInRelease{2020/02/02}%
+%<latexrelease> {\DeclareFontSeriesDefault}{Custom series}%
+% \end{macrocode}
+%
+% One problem with the NFSS approach of handling the series axis
+% turned out to be that (especially with respect to ``boldness'')
+% different font families implemented different strategies. For
+% example, with Computer Modern fonts you normally only have
+% \texttt{bx} whereas most PostScript fonts offered only \texttt{b}
+% but not \texttt{bx}. As a result \LaTeX's standard setting for
+% \cs{bfdefault} didn't work with such fonts, but if it got changed
+% to produce \texttt{b}, then that didn't work with Computer Modern
+% if the fonts got combined (e.g., using Computer Modern Typewriter
+% with such fonts).
+%
+% The solution back then was to provide substitution rules in the
+% font \texttt{.fd} such that if a \texttt{bx} series got requested
+% the \texttt{b} series got used. While this works in that
+% particular case, it isn't a very
+% general solution. For example, if you happen to have a font family that
+% has several weights you may want to typeset the whole document
+% in a somewhat lighter or darker font but if you then modify
+% \cs{mddefault} to allow for this, then of course your change only
+% works with that particular family but not with the typewriter
+% or sans serif family you also want to use.
+%
+% A better solution was provided by the \texttt{mweights} package by
+% Bob Tennent that offers defaults on the level of the three main
+% font families in the document: for ``rm'', ``sf'' and ``tt'' so
+% that font packages could define defaults for the sans serif
+% document font by providing \cs{bfseries@sf} which then was used
+% when \cs{bfseries} got executed and the current family was the
+% \cs{sffamily}.
+%
+% \DescribeMacro\DeclareFontSeriesDefault
+% We now support this concept directly from within \LaTeX{} and for
+% use in font packages (or the document preamble) we offer
+% \cs{DeclareSeriesDefault}. This declaration takes three
+% arguments:
+% \begin{description}
+% \item[document family interface:] Can either be \texttt{rm},
+% \texttt{sf} or \texttt{tt}. This is optional and if not given the
+% overall default.
+% \item[document series interface:] Can be \texttt{md} or
+% \texttt{bf}.
+% \item[series value:] This is the value that is going to be used
+% with the combination is requested.
+% \end{description}
+%
+% For example, \verb=\DeclareFontSeriesDefault[rm]{bf}{sb}= would
+% use \texttt{sb} (semi-bold) when \cs{rmfamily} \cs{bfseries} is
+% asked for.
+%
+% If used without the optional argument, e.g.,
+% \verb=\DeclareFontSeriesDefault{bf}{b}= then this is like
+% redefining \cs{bfdefault} or \cs{mddefault}.
+%
+% If some family specify defaults aren't given, e.g. if there are
+% no declarations for, say, \texttt{tt} then the format defaults
+% of \cs{mddefault} and \cs{bfdefault} are assumed. If those are
+% later changed this is \emph{not} reflected!\footnote{I see no
+% easy way to achieve this without compromising compatibility with
+% existing packages that currently use \textsf{mweights} and directly
+% define (some) of the \cs{mdseries@..} commands but not others.}
+%
+%
+%
+% \begin{macro}{\DeclareFontSeriesDefault}
+% The command to declare font series defaults for the ``rm'', ``sf'' or
+% ``tt'' family.
+% \begin{macrocode}
+\newcommand\DeclareFontSeriesDefault[3][]{%
+ \def\@reserveda{#1}%
+% \end{macrocode}
+% No optional argument: set up general default.
+% \begin{macrocode}
+ \ifx\@resereda\@empty
+ \ifcsname #2series\endcsname % supported are
+ % \[md/bf]default
+ \expandafter\def
+ \csname #2default\endcsname{#3}%
+ \else
+ \@latex@error{Wrong syntax for \string\DeclareFontSeriesDefault}%
+ {Mandatory first argument must be 'md' or 'bf'.}
+ \fi
+% \end{macrocode}
+% Optional argument given, set up specific default.
+% \begin{macrocode}
+ \else
+ \ifcsname #2series@#1\endcsname % supported are
+ % \[md/bf]series@[rm/sf/tt]
+ \expandafter\edef
+ \csname #2series@#1\endcsname{#3}%
+% \end{macrocode}
+%
+% If the interface is used we remove the frozen kernel
+% default. This way, we know that something was explicitly set up
+% (even if the setup has the same value as the default).
+% \begin{macrocode}
+ \expandafter\let
+ \csname #2series@#1@kernel\endcsname\@undefined
+ \else
+ \@latex@error{Wrong syntax for \string\DeclareFontSeriesDefault}%
+ {Optional first argument must be 'rm', 'sf', or 'tt'. \MessageBreak
+ Second argument must be 'md' or 'bf'.}
+ \fi
+ \fi
+}
+% \end{macrocode}
+% \end{macro}
+
+
+
+
+% \begin{macro}{\mdseries@rm}
+% \begin{macro}{\mdseries@sf}
+% \begin{macro}{\mdseries@tt}
+% \begin{macro}{\bfseries@rm}
+% \begin{macro}{\bfseries@sf}
+% \begin{macro}{\bfseries@tt}
+% We initialize the family specific default at the end of the
+% format generation. Later on they may get overwritten in the
+% preamble or a package via \cs{DeclareFontSeriesDefault} (or
+% possibly directly).
+%
+% Conceptual change: The \cs{bfdefault} will be \texttt{b} not
+% \texttt{bx} because that is what it should be really for nearly
+% every font except Computer/Latin Modern.
+%
+% To account for the fact that by default we typeset in CM or LM we
+% set up the \cs{bfseries@..} defaults to use \texttt{bx} instead.
+%
+% This means that it behaves like before because if the default
+% fonts are used then \cs{bfseries@rm} etc kick in and make
+% \cs{textbf} use \texttt{bx}. However, if the font gets changed
+% then \cs{bfdefault} will get used.
+%
+% \begin{macrocode}
+\def\bfseries@rm{bx}
+\def\bfseries@sf{bx}
+\def\bfseries@tt{bx}
+% \end{macrocode}
+%
+% Frozen version of the kernel defaults so we can see if they have changed.
+% \begin{macrocode}
+\let\bfseries@rm@kernel\bfseries@rm
+\let\bfseries@sf@kernel\bfseries@sf
+\let\bfseries@tt@kernel\bfseries@tt
+% \end{macrocode}
+%
+% The default for the medium series is \texttt{m} and this will be
+% interpreted as resetting both weight and width. To reset only one
+% of them the virtual value \texttt{?m} and \texttt{m?} are available.
+% \begin{macrocode}
+\def\mdseries@rm{m}
+\def\mdseries@sf{m}
+\def\mdseries@tt{m}
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+
+
+
+% \begin{macro}{\expand@font@defaults}
+%
+% The family specific defaults are fully expanded, i.e., they are
+% defined via \cs{edef} inside \cs{DeclareFontSeriesDefault}.
+% However, the overall defaults, e.g., \cs{bfdefault} may have been
+% redefined by the user and thus may not be fully expanded. So to
+% enable reliable comparison we make expanded versions of
+% them. That we rerun each time. The alternative would be to only
+% allow for changes before begin document.
+% \begin{macrocode}
+\def\expand@font@defaults{%
+ \edef\rmdef@ult{\rmdefault}%
+ \edef\sfdef@ult{\sfdefault}%
+ \edef\ttdef@ult{\ttdefault}%
+ \edef\bfdef@ult{\bfdefault}%
+ \edef\mddef@ult{\mddefault}%
+ \edef\famdef@ult{\familydefault}%
+}
+% \end{macrocode}
+%
+% \end{macro}
+
+
+
+% \begin{macro}{\bfseries}
+% This document command switches to the bold series.
+% \begin{macrocode}
+\DeclareRobustCommand\bfseries{%
+ \not@math@alphabet\bfseries\mathbf
+% \end{macrocode}
+% In the original NFSS definition it then called \cs{fontseries}
+% with the value \cs{bfdefault}. In the new scheme we have more
+% alternatives and therefore check if the current family
+% (\cs{f@family}) is the current \cs{rmdef@ult}, \cs{sfdef@ult} or
+% \cs{ttdef@ult} and the select the correct family default in that case.
+% \begin{macrocode}
+ \expand@font@defaults
+ \fontseries{%
+ \ifx\f@family\rmdef@ult \bfseries@rm
+ \else\ifx\f@family\sfdef@ult \bfseries@sf
+ \else\ifx\f@family\ttdef@ult \bfseries@tt
+% \end{macrocode}
+% If not \cs{bfdefault} is used.
+% \begin{macrocode}
+ \else \bfdefault
+ \fi\fi\fi
+ }%
+ \selectfont
+}
+% \end{macrocode}
+% \end{macro}
+
+
+
+% \begin{macro}{\mdseries}
+% This document command switches to the medium series.
+% \begin{macrocode}
+\DeclareRobustCommand\mdseries{%
+ \not@math@alphabet\mdseries\relax
+ \expand@font@defaults
+ \fontseries{%
+ \ifx\f@family\rmdef@ult \mdseries@rm
+ \else\ifx\f@family\sfdef@ult \mdseries@sf
+ \else\ifx\f@family\ttdef@ult \mdseries@tt
+ \else \mddefault
+ \fi\fi\fi
+ }%
+ \selectfont
+}
+% \end{macrocode}
+% \end{macro}
+
+
+% \begin{macro}{\rmfamily}
+% Here are the document level commands for changing the main font
+% families, or rather, here is a documented outline of the code,
+% the actual code is then streamlined and somewhat generalized.
+%\begin{verbatim}
+%\DeclareRobustCommand\rmfamily{%
+% \not@math@alphabet\rmfamily\mathrm
+%\end{verbatim}
+% If families are changed then we have to do a bit more work.
+% In the original NFSS implementation
+% a family change kept encoding, series shape and size unchanged
+% but now we can't any
+% longer simply reuse the current series value. Instead we may have
+% to change it from one family default to the next.
+%\begin{verbatim}
+% \expand@font@defaults
+%\end{verbatim}
+% We have to do the testing while while the current family is still
+% unchanged but we have to do the adjustment of the series after it
+% got changed (because the new family might has different sets
+% ofshapes available and we certainly don't want to see
+% substituation going on. So we use \cs{target@series@value} to
+% hold the target series (if any).
+%\begin{verbatim}
+% \let\target@series@value\@empty
+%\end{verbatim}
+% Thus, if the current family is the sans family
+%\begin{verbatim}
+% \ifx\f@family\sfdef@ult
+%\end{verbatim}
+% and if we using the medium series of the sans family
+%\begin{verbatim}
+% \ifx\f@series\mdseries@sf
+%\end{verbatim}
+% then lets switch to the medium series for the serif family
+%\begin{verbatim}
+% \let\target@series@value\mdseries@rm
+%\end{verbatim}
+% and if we use the bold series of the sans family switch to the
+% bold default of the serif family:
+%\begin{verbatim}
+% \else\ifx\f@series\bfseries@sf \let\target@series@value\bfseries@rm
+%\end{verbatim}
+% However, the sans family may not have any specific defaults set,
+% so we also compare with the overall defaults.
+%\begin{verbatim}
+% \else\ifx\f@series\mddef@ult \let\target@series@value\mdseries@rm
+% \else\ifx\f@series\bfdef@ult \let\target@series@value\bfseries@rm
+%\end{verbatim}
+% If neither test was true we leave the series alone. This way a
+% special manual setting such as \verb=\fontseries{lc}= is not
+% undone if the family changes (of course there may not be any
+% support for it in the new family but then the NFSS
+% substitution kicks in and sorts it out).
+%\begin{verbatim}
+% \fi\fi\fi\fi
+%
+%\end{verbatim}
+% We need to do the same if the current family is the typewriter family:
+%\begin{verbatim}
+% \else\ifx\f@family\ttdef@ult
+% \ifx\f@series\mdseries@tt \let\target@series@value\mdseries@rm
+% \else\ifx\f@series\bfseries@tt \let\target@series@value\bfseries@rm
+% \else\ifx\f@series\mddef@ult \let\target@series@value\mdseries@rm
+% \else\ifx\f@series\bfdef@ult \let\target@series@value\bfseries@rm
+% \fi\fi\fi\fi
+% \fi\fi
+%\end{verbatim}
+% With these preparations for series out of the way we can now
+% change the font family to \cs{rmdefault}.
+%\begin{verbatim}
+% \fontfamily\rmdefault
+%\end{verbatim}
+%
+% If \cs{target@series@value} is still empty there is nothing more
+% to do other than selecting the new family. However, if not then
+% we should update the font series now as well. But there is one
+% further subtle issue. We may not have loaded an \texttt{.fd} file
+% for our target font family yet. In the past that was done in
+% \cs{selectfont} if necessary but since we are now doing all the
+% comparisons in \cs{fontseries} we need to make sure that the font
+% family specifications are already loaded prior to calling
+% \cs{fontseries}.
+%\begin{verbatim}
+% \ifx\target@series@value\@empty \else
+% \maybe@load@fontshape
+%\end{verbatim}
+% Updating the series in this case means directly changing
+% \cs{f@series} to the target value. We don't want to go through
+% \cs{fontseries} because that would apply the mappings and then
+% \texttt{bx + b} would keep \texttt{bx} instead of changing to
+% \texttt{b} as desired.
+% as
+%\begin{verbatim}
+% \let\f@series\target@series@value
+% \fi
+% \selectfont}
+%\end{verbatim}
+%
+% So now for the real definition: most of the code above gets
+% delegated to a helper command \cs{prepare@family@series@update}
+% so that the definition becomes again fairly short. In addition we
+% add a hook, mainly for our Japanese friends so that the code can
+% be extended prior to the call to \cs{selectfont}.
+%
+% \changes{v3.1f}{2020/01/11}{Streamlined implementation with hook}
+% \begin{macrocode}
+\DeclareRobustCommand\rmfamily{%
+ \not@math@alphabet\rmfamily\mathrm
+% \end{macrocode}
+% This holds all the code discussed above, first argument is the
+% meta family, i.e., \texttt{rm} in this case, and second argument
+% is the default family name, e.g., \texttt{cmr} indirectly
+% accessed via \cs{rmdefault}. This is calling \cs{fontfamily} and
+% if necessary \cs{fontseries} as outline above.
+% \begin{macrocode}
+ \prepare@family@series@update{rm}\rmdefault
+% \end{macrocode}
+% The comes the hook code (by default a no-op) and finally the call
+% to \cs{selectfont}.
+% \begin{macrocode}
+ \@rmfamilyhook
+ \selectfont}
+% \end{macrocode}
+%
+% \begin{macro}{\sffamily}
+% \begin{macro}{\ttfamily}
+% The definitions for \cs{sffamily} and \cs{ttfamily} are similar,
+% the differences are only in what font families get checked.
+% \changes{v3.1f}{2020/01/11}{Streamlined implementation with hook}
+% \begin{macrocode}
+\DeclareRobustCommand\sffamily{%
+ \not@math@alphabet\sffamily\mathsf
+ \prepare@family@series@update{sf}\sfdefault
+ \@sffamilyhook
+ \selectfont}
+% \end{macrocode}
+%
+% \changes{v3.1f}{2020/01/11}{Streamlined implementation with hook}
+% \begin{macrocode}
+\DeclareRobustCommand\ttfamily{%
+ \not@math@alphabet\ttfamily\mathtt
+ \prepare@family@series@update{tt}\ttdefault
+ \@ttfamilyhook
+ \selectfont}
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+%
+% \begin{macro}{\@rmfamilyhook}
+% \begin{macro}{\@sffamilyhook}
+% \begin{macro}{\@ttfamilyhook}
+% By default the hooks do nothing.
+% \begin{macrocode}
+\let\@rmfamilyhook\@empty
+\let\@sffamilyhook\@empty
+\let\@ttfamilyhook\@empty
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+
+
+
+% \begin{macro}{\prepare@family@series@update}
+% This is core command that prepares for the family update. The big
+% difference to the documented code above is that the nested
+% \cs{ifx} statements seem to be missing. Instead we loop through
+% an internal list that holds the names of the three meta
+% families. This approach allows us to extend the mechanism at a
+% later stage to allow for additional named meta families.
+%
+% \begin{macro}{\@meta@family@list}
+% Here is the current definition of that list:
+% \begin{macrocode}
+\def\@meta@family@list{\@elt{rm}\@elt{sf}\@elt{tt}}
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macrocode}
+\def\prepare@family@series@update#1#2{%
+ \expand@font@defaults
+% \end{macrocode}
+% We prepare for changing the current series. We have to find it
+% before changing the family as discussed above.
+% \begin{macrocode}
+ \let\target@series@value\@empty
+ \def\target@meta@family@value{#1}%
+% \end{macrocode}
+% To find it we loop over the meta family list with a suitable
+% definition of \cs{@elt}.
+% \begin{macrocode}
+ \let\@elt\update@series@target@value
+ \@meta@family@list
+ \let\@elt\relax
+% \end{macrocode}
+% That will figure out the correct series value to use without updating
+% it. Now we can change the family.
+% \begin{macrocode}
+ \fontfamily#2%
+% \end{macrocode}
+% After that we update the series. That code is again like the one
+% above.
+% \begin{macrocode}
+ \ifx\target@series@value\@empty
+ \else
+ \maybe@load@fontshape
+ \let\f@series\target@series@value
+ \fi
+}
+% \end{macrocode}
+% \end{macro}
+%
+%
+%
+% \begin{macro}{\update@series@target@value}
+% In this macro used in the look you basically find the nested
+% \cs{ifx}s from the outline above. The only difference is that is
+% it is parameterized instead of being written out and only for one
+% block of tests because the code is called reatedly when looping
+% over the meta family list. From the list we get each meta family
+% name in turn.
+% \begin{macrocode}
+\def\update@series@target@value#1{%
+% \end{macrocode}
+% There is one additional test at the beginning, because the list
+% contains all meta families and we need to ignore the case where
+% current one from the list and target one are identical.
+% \begin{macrocode}
+ \def\@reserveda{#1}%
+ \ifx\target@meta@family@value\@reserveda % rm -> rm do nothing
+ \else
+% \end{macrocode}
+% We only ``do'' something if the current font family matches the
+% current meta family.
+% \begin{macrocode}
+ \expandafter\ifx\csname#1def@ult\endcsname\f@family
+% \end{macrocode}
+% If that's the case we know that this is the block that applies
+% (only one meta family can match). So to speed things up we
+% change \cs{@elt} so that the rest of the loop gets gobbled.
+% \begin{macrocode}
+ \let\@elt\@gobble
+% \end{macrocode}
+% Then we try to find the right new value for the series (as
+% explained above). The two macros defined first are only there
+% because we now need to use \cs{csname} and this way the code will
+% be a little faster.
+% \begin{macrocode}
+ \expandafter\let\expandafter\@reservedb
+ \csname mdseries@\target@meta@family@value\endcsname
+ \expandafter\let\expandafter\@reservedc
+ \csname bfseries@\target@meta@family@value\endcsname
+% \end{macrocode}
+% This here is now identical to the nested \cs{ifx} block from the
+% outline, except that it there appeared twice in
+% \cs{rmfamily}. This is now covered by looping and stopping the
+% loop when a match was found.
+% \begin{macrocode}
+ \expandafter\ifx\csname mdseries@#1\endcsname\f@series
+ \let\target@series@value\@reservedb
+ \else\expandafter\ifx\csname bfseries@#1\endcsname\f@series
+ \let\target@series@value\@reservedc
+ \else\ifx\f@series\mddef@ult \let\target@series@value\@reservedb
+ \else\ifx\f@series\bfdef@ult \let\target@series@value\@reservedc
+ \fi\fi\fi\fi
+ \fi
+ \fi
+}
+% \end{macrocode}
+% \end{macro}
+%
+%
+%
+%
+%
+%
+%
+%
+%
+% \begin{macro}{\init@series@setup}
+% This is code to be run at begin document \ldots
+% \begin{macrocode}
+\def\init@series@setup{%
+% \end{macrocode}
+%
+% We only want \texttt{bx} in \cs{bfseries@rm} if the roman font is
+% Computer Modern or Latin Modern, otherwise it should be
+% \texttt{b}. It was set to \texttt{bx} in the kernel so that any
+% font use with the default families in the preamble get this
+% value. Now at the real document start we check if the fonts have
+% been changed. If there was a \cs{DeclareFontSeriesDefault}
+% declaration or \cs{bfseries@rm} was directly altered then it
+% differs from \cs{bfseries@rm@kernel} and we do nothing.
+% Otherwise we check if \cs{rmdefault} is one of the CM/LM font
+% families and if so we keep \texttt{bx} otherwise we change it to
+% \texttt{b}.
+%
+% This approach doesn't cover one case: CM/LM got changed to a
+% different family that supports \texttt{bx}, but the support
+% package for that family used \verb=\def\bfseries@rm{bx}= instead
+% of using \cs{DeclareFontSeriesDefault}. In that case the code
+% here changes it to \texttt{b}. Solution: use the
+% \cs{DeclareFontSeriesDefault} interface.
+% \begin{macrocode}
+ \ifx\bfseries@rm@kernel\bfseries@rm
+ \expandafter\in@\expandafter{\rmdefault}{cmr,cmss,cmtt,lcmss,lcmtt,lmr,lmss,lmtt}%
+ \ifin@ \else \def\bfseries@rm{b}\fi\fi
+% \end{macrocode}
+% Same approach for \cs{bfseries@sf} and \cs{bfseries@tt}:
+% \begin{macrocode}
+ \ifx\bfseries@sf@kernel\bfseries@sf
+ \expandafter\in@\expandafter{\sfdefault}{cmr,cmss,cmtt,lcmss,lcmtt,lmr,lmss,lmtt}%
+ \ifin@ \else \def\bfseries@sf{b}\fi\fi
+ \ifx\bfseries@tt@kernel\bfseries@tt
+ \expandafter\in@\expandafter{\ttdefault}{cmr,cmss,cmtt,lcmss,lcmtt,lmr,lmss,lmtt}%
+ \ifin@ \else \def\bfseries@tt{b}\fi\fi
+% \end{macrocode}
+%
+% If the document preamble has changed the \cs{familydefault} or if
+% the if the \cs{rmdefault} contains a new font family, we have to
+% adjust the series defaults accordingly, before starting
+% typesetting.
+%
+% On the other hand if we still typeset in CM or LM then
+% \cs{bfdefault} is wrong since it is now saying \texttt{b} and not
+% \texttt{bx}.
+
+% To fix this we run \cs{rmfamily}, \cs{sffamily} or
+% \cs{ttfamily} depending on the situation and this will correct
+% the setup for us.
+% \begin{macrocode}
+ \expand@font@defaults
+ \ifx\famdef@ult\rmdef@ult \rmfamily
+ \else\ifx\famdef@ult\sfdef@ult \sffamily
+ \else\ifx\famdef@ult\ttdef@ult \ttfamily
+ \fi\fi\fi
+}%
+% \end{macrocode}
+% \end{macro}
+%
+%
+%
+% As the kernel code now implements the same functionality as
+% \textsf{mweights}, albeit internally coded slightly differently,
+% that package shouldn't be loaded any more. We therefore pretend
+% that it already got loaded. Thus, a font package that tries to
+% load it and then sets \cs{mdseries@..}, etc.\ will continue to
+% work but will now use the kernel code.
+%
+% Of course, mid-term such package should probably use
+% \cs{DeclareFontSeriesDefault} instead of making using low-level
+% definitions.
+%
+% \begin{macrocode}
+\expandafter\let\csname ver@mweights.sty\endcsname\fmtversion
+% \end{macrocode}
+%
+%
+%
+% \begin{macrocode}
+%</2ekernel|latexrelease>
+%<latexrelease>\EndIncludeInRelease
+%<latexrelease>\IncludeInRelease{0000/00/00}%
+%<latexrelease> {\DeclareFontSeriesDefault}{Custom series}%
+%<latexrelease>
+%<latexrelease>\let\DeclareFontSeriesDefault\@undefined
+%<latexrelease>\let\bfseries@rm\@undefined
+%<latexrelease>\let\bfseries@sf\@undefined
+%<latexrelease>\let\bfseries@tt\@undefined
+%<latexrelease>\let\bfseries@rm@kernel\@undefined
+%<latexrelease>\let\bfseries@sf@kernel\@undefined
+%<latexrelease>\let\bfseries@tt@kernel\@undefined
+%<latexrelease>\let\mdseries@rm\@undefined
+%<latexrelease>\let\mdseries@sf\@undefined
+%<latexrelease>\let\mdseries@tt\@undefined
+%<latexrelease>\let\expand@font@defaults\@undefined
+%<latexrelease>\expandafter\let\csname ver@mweights.sty\endcsname\@undefined
+%<latexrelease>
+%<latexrelease>\DeclareRobustCommand\bfseries
+%<latexrelease> {\not@math@alphabet\bfseries\mathbf
+%<latexrelease> \fontseries\bfdefault\selectfont}
+%<latexrelease>\DeclareRobustCommand\mdseries
+%<latexrelease> {\not@math@alphabet\mdseries\relax
+%<latexrelease> \fontseries\mddefault\selectfont}
+%<latexrelease>\DeclareRobustCommand\rmfamily
+%<latexrelease> {\not@math@alphabet\rmfamily\mathrm
+%<latexrelease> \fontfamily\rmdefault\selectfont}
+%<latexrelease>\DeclareRobustCommand\sffamily
+%<latexrelease> {\not@math@alphabet\sffamily\mathsf
+%<latexrelease> \fontfamily\sfdefault\selectfont}
+%<latexrelease>\DeclareRobustCommand\ttfamily
+%<latexrelease> {\not@math@alphabet\ttfamily\mathtt
+%<latexrelease> \fontfamily\ttdefault\selectfont}
+%<latexrelease>
+%<latexrelease>\let\@rmfamilyhook\@undefined
+%<latexrelease>\let\@sffamilyhook\@undefined
+%<latexrelease>\let\@ttfamilyhook\@undefined
+%<latexrelease>\let\@meta@family@list\@undefined
+%<latexrelease>\let\prepare@family@series@update\@undefined
+%<latexrelease>\let\update@series@target@value\@undefined
+%<latexrelease>
+% \end{macrocode}
+% This is always called in \cs{document} so don't make it undefined.
+% \begin{macrocode}
+%<latexrelease>\let\init@series@setup\relax
+%<latexrelease>
+%<latexrelease>\EndIncludeInRelease
+%<*2ekernel>
+% \end{macrocode}
+
+%
+%
+%
+% \section{Supporting nested emphasis}
+%
+% By default \LaTeXe{} supports two levels of nested emphasis: if
+% the current font has an upright shape then it switches to
+% \cs{itshape} otherwise to \cs{eminnershape} (which defaults to
+% \cs{upshape}). This means nested emphasis will ocssilate between
+% italic and upright shapes.
+%
+% Sometimes it would be nice to allow for a more lengthly sequence,
+% but instead of providing a fixed one \LaTeX{} now offers a
+% general mechanism that allows to define arbitrary sequences.
+%
+% \DescribeMacro\DeclareEmphSequence
+% \DescribeMacro\emforce
+%
+% This declaration expects a comma separated list of (font) change
+% declarations corresponding to increasing levels of emphasis.
+% The mechanism tries to be ``smart'' and verifies that the
+% declarations actually alter the font. If not it will ignore this
+% level and tries the next one---the assumption being that
+% there was a manual font change in the document to the font that
+% is now supposed to be used for emphasis. Of course, this only
+% works if the declarations in the list actually change the font
+% and not, say, just the color.
+% In such a case one has to use \cs{emforce} to which directs the
+% mechanism to use the level even if the font attributes haven't changed.
+%
+% \DescribeMacro\emreset
+% If the nesting is so deep, that the specified levels are
+% exhausted then \cs{emreset} is used as a final set of
+% declarations (which by default returns
+% back to the upright shape). Any additional nesting levels will
+% then reuse the list from its beginning.
+%
+%
+%
+% \begin{macro}{\DeclareEmphSequence}
+%
+% \cs{DeclareEmphSequence} expects a clist of declaration. Spaces in the
+% argument are dropped to avoid surious spaces in the output. The
+% declarations are additive. At the very end the shape is reset
+% using |\emreset| and |\emforce| so that this case is never
+% skipped.\footnote{Maybe we should not add \cs{emforce} but allow
+% that case to be skipped as well. Of course, that might result in
+% an endless loop if somebody defines a sequence without any font
+% change and without \cs{emforce} but \ldots}
+% Further nested calls restart at the beginning.
+% \changes{v3.1e}{2019/12/17}{Provide \cs{emph} sequences}
+% \begin{macrocode}
+%</2ekernel>
+%<*2ekernel|latexrelease>
+%<latexrelease>\IncludeInRelease{2020/02/02}%
+%<latexrelease> {\DeclareEmphSequence}{Nested emph}%
+\def\DeclareEmphSequence#1{%
+ \protected@edef\emfontdeclare@clist{\zap@space#1, \@empty\emforce\emreset}%
+}
+% \end{macrocode}
+% By default the it is empty, in which case \cs{eminnershape} is
+% used by \LaTeX.
+% \begin{macrocode}
+\let\emfontdeclare@clist\@empty
+% \end{macrocode}
+% \end{macro}
+
+
+
+% \begin{macro}{\emrest}
+% Reset the font to upright and upper/lower case. With the default rules
+% using \cs{shapedefault} does that for us but to be on the safe side we
+% do it like this:
+% \begin{macrocode}
+\DeclareRobustCommand\emreset{\upshape\ulcshape}
+% \end{macrocode}
+% \end{macro}
+
+
+
+% \begin{macro}{\em}
+% The new definition for \cs{em} (and implicitly \cs{emph} is like
+% it was before if \cs{emfontdeclare@clist} is empty.
+% \begin{macrocode}
+\DeclareRobustCommand\em{%
+ \@nomath\em
+ \ifx\emfontdeclare@clist\@empty
+ \ifdim \fontdimen\@ne\font >\z@
+ \eminnershape \else \itshape \fi
+ \else
+% \end{macrocode}
+% But if not we use the list to decide how to do emphasis.
+%
+% We use the current font to check if the declarations have any
+% effect, so even a size change is allowed and identified as a
+% modification (but a color change, for example, isn't). So first
+% we save the current status.
+% \begin{macrocode}
+ \edef\em@currfont{\csname\curr@fontshape/\f@size\endcsname}%
+% \end{macrocode}
+% Then we grab the next element from the list and check if it can
+% be used.
+% \begin{macrocode}
+ \expandafter\do@emfont@update\emfontdeclare@clist\do@emfont@update
+ \fi
+}
+% \end{macrocode}
+%
+% \begin{macrocode}
+\def\eminnershape{\upshape}
+% \end{macrocode}
+% \end{macro}
+%
+%
+%
+% \begin{macro}{\do@emfont@update}
+% We know that the list (if not empty) has at least 2 elements
+% separated by a comma, so we pick up the first in \texttt{\#1} and
+% the rest in \texttt{\#2}.
+% \begin{macrocode}
+\def\do@emfont@update#1,#2\do@emfont@update{%
+% \end{macrocode}
+% First action is to alter the list and move the first entry to the end
+% \begin{macrocode}
+ \def\emfontdeclare@clist{#2,#1}%
+% \end{macrocode}
+% Then we execute current declaration. Appending |\selectfont| means one
+% can write just |\fontshape{it}}| and that works then too.
+% \begin{macrocode}
+% \typeout{Use: \detokenize{#1}}%
+ #1\selectfont
+% \end{macrocode}
+% We then compare the current font with our saved version, but with
+% a slight twist: we add \cs{em@force} at the end of the
+% name. Normally this is empty so has no effect but if there was an
+% \cs{emforce} as part of \texttt{\#1} it will append a |/| to the
+% font name (making it invalid) thus this will then always fail the
+% test.
+%
+% If the test fails we are done and the declarations will be used.
+% Otherwise we will try the next declaration in the sequence.
+% \begin{macrocode}
+ \expandafter\ifx\csname \curr@fontshape/\f@size\em@force
+% \end{macrocode}
+% For the comparison with \cs{ifx} we have to exand
+% \cs{em@currfont} once as the relevant info is inside.
+% \begin{macrocode}
+ \expandafter\endcsname
+ \em@currfont
+ \expandafter\do@emfont@update\emfontdeclare@clist\do@emfont@update
+% \end{macrocode}
+% If \cs{emforce} was used, we have to undo its effect:
+% \begin{macrocode}
+ \else
+ \let\em@force\@empty
+ \fi
+}
+% \end{macrocode}
+% \end{macro}
+
+
+
+% \begin{macro}{\emforce}
+% \begin{macro}{\em@force}
+% The definition of \cs{emforce} is simple: change \cs{em@force} to
+% make the above test always invalid.
+% \begin{macrocode}
+\protected\def\emforce{\def\em@force{/}}
+\let\em@force\@empty
+%</2ekernel|latexrelease>
+%<latexrelease>\EndIncludeInRelease
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+
+
+
+%
% \begin{macro}{\em}
% \changes{v1.2b}{1990/01/28}{Call to \cs{@nomath} added.}
% \changes{v3.1a}{2015/01/09}{Allow \cs{emph} to produce small caps (latexrelease)}
% \begin{macro}{\eminnershape}
% \changes{v3.1a}{2015/01/09}{macro added (latexrelease)}
+%
+% These are the older definitions for \cs{em}, prior to 2020.
+%
% We also have to define the {\em emphasize\/} font change command
% (i.e.\ |\em|). This command will look is the current font is
% sloped (i.e.\ has a positive |\fontdimen1|) and will then
% select either |\upshape| or |\itshape|.
% \begin{macrocode}
-%</2ekernel>
-%<latexrelease>\IncludeInRelease{2015/01/01}{\eminnershape}{\eminnershape}%
-%<*2ekernel|latexrelease>
-\DeclareRobustCommand\em
- {\@nomath\em \ifdim \fontdimen\@ne\font >\z@
- \eminnershape \else \itshape \fi}%
-% \end{macrocode}
-%
-% \begin{macrocode}
-\def\eminnershape{\upshape}%
-%</2ekernel|latexrelease>
+%<latexrelease>\IncludeInRelease{2015/01/01}{\DeclareEmphSequence}{Nested emph}%
+%<latexrelease>\let\DeclareEmphSequence\@undefined
+%<latexrelease>\let\emfontdeclare@clist\@undefined
+%<latexrelease>\let\emreset\@undefined
+%<latexrelease>\let\do@emfont@update\@undefined
+%<latexrelease>\let\emforce\@undefined
+%<latexrelease>\let\em@force\@undefined
+%<latexrelease>
+%<latexrelease>\DeclareRobustCommand\em
+%<latexrelease> {\@nomath\em \ifdim \fontdimen\@ne\font >\z@
+%<latexrelease> \eminnershape \else \itshape \fi}%
%<latexrelease>\EndIncludeInRelease
-%<latexrelease>\IncludeInRelease{0000/00/00}{\eminnershape}{\eminnershape}%
+%<latexrelease>
+%<latexrelease>\IncludeInRelease{0000/00/00}{\DeclareEmphSequence}{Nested emph}%
%<latexrelease>\DeclareRobustCommand\em
%<latexrelease> {\@nomath\em \ifdim \fontdimen\@ne\font >\z@
%<latexrelease> \upshape \else \itshape \fi}%
@@ -230,6 +1076,12 @@
% \end{macro}
%
%
+
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+%
% \begin{macro}{\not@math@alphabet}
% This function generates an error message when it is called in
% math mode. The same function should be defined in
@@ -331,35 +1183,6 @@
% \end{macro}
%
%
-% \begin{macro}{\oldstylenums}
-% This macro implements old style numerals but only works if we
-% assume that the standard math fonts are used. Thus it needs
-% changing in case other math encodings are used.
-% \begin{macrocode}
-\DeclareRobustCommand\oldstylenums[1]{%
- \begingroup
-% \end{macrocode}
-% Provide spacing using the interword space of the current font.
-% \begin{macrocode}
- \spaceskip\fontdimen\tw@\font
-% \end{macrocode}
-% Then switch to the math italic font. We don't change the current
-% value of |\f@series| which means that you can use bold numerals
-% if |\bfseries| is in force. As family we use |\rmdefault| which
-% means that this only works if there exist an |OML| encoded
-% version of that font or rather a corresponding |.fd| file (which
-% is the case for standard \LaTeX{} fonts even though they only
-% contain substitutions).
-% \changes{v3.0j}{1999/02/12}{Use \cs{rmdefault} instead of \texttt{cmm}
-% (pr/2954)}
-% \begin{macrocode}
- \usefont{OML}{\rmdefault}{\f@series}{it}%
- \mathgroup\symletters #1%
- \endgroup
-}
-% \end{macrocode}
-% \end{macro}
-%
% \begin{macro}{\hexnumber@}
% To set up \LaTeX's special math character
% definitions we first provide a macro to generate hexadecimal
@@ -528,6 +1351,7 @@
\let\@addtofilelist\@gobble
% \end{macrocode}
%
+%
% Ditto for math although I don't think that we will get a lot of
% customisation :-)
% \begin{macrocode}