[latex3-commits] [git/LaTeX3-latex3-latex2e] nfssaxes: documentation and a few rule changes (31e9b1f3)

[Frank Mittelbach]

Repository : https://github.com/latex3/latex2e
On branch  : nfssaxes
Link       : https://github.com/latex3/latex2e/commit/31e9b1f3361b886b9ca884cf87af5a91867fcba1

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

commit 31e9b1f3361b886b9ca884cf87af5a91867fcba1
Author: Frank Mittelbach <frank.mittelbach at latex-project.org>
Date:   Fri Oct 11 15:56:26 2019 +0200

    documentation and a few rule changes


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

31e9b1f3361b886b9ca884cf87af5a91867fcba1
 base/nfssaxes.tex | 59 +++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 13 deletions(-)

diff --git a/base/nfssaxes.tex b/base/nfssaxes.tex
index d43560d4..2021e50e 100644
--- a/base/nfssaxes.tex
+++ b/base/nfssaxes.tex
@@ -41,12 +41,47 @@
 % allow for setting up explicit exceptions nicely (not sure that that
 % would ever get used though).
 %
-% \emph{What is missing, is a way to state on document level that one
-% wants to revert, say, the weight to ``regular'' but keep the width
-% or vize versa. But maybe this is overkill and \cs{bfseries} and
-% \cs{mdseries} is all that people need in practice.}
+% Design considerations for mapping entries:
+% \begin{itemize}
+% \item
 %
-% \emph{explain rationale and m?/?m syntax}
+%    We make \texttt{m} to reset both weight and width (as this is
+%    how it always worked). To reset just the width \textt{?m} is
+%    provided and to reset just the weight \texttt{m?}.
+%
+% \item
+%
+%    If there is no table entry then the target series is used
+%    unconditionally. This means that any request to set both weight
+%    and width (e.g. \texttt{bx} or \texttt{ulc}) needs no table
+%    entries.
+%    for tht reason there are no entries which have a weight+width
+%    request (as second argument).
+%
+% \item
+%
+%    Only a few entries have ``alterative'' values and perhaps most of
+%    them should get dropped. Or maybe not \ldots{} needs some thought
+%    perhaps.
+%
+%    The idea is that you don't want the normal substitution to kick
+%    in because that would reset the shape first and it may be better
+%    to stay with \texttt{b} when a change to \texttt{c} is requested
+%    and \texttt{bc} doesn't exist, than to go to first change the
+%    shape to \texttt{n} and then find that \texttt{bc/n} doesn't
+%    exist either and thus ending up wth \texttt{m/n}.
+%
+% \item
+%
+%    Also: while I did set up all nine standard weight values from
+%    \texttt{ul} to \textt{ub} I only bothered to provide entries for
+%    \texttt{c} and \texttt{x}, because other levels of
+%    compression/expansion are really really seldom.
+%
+%    Could and perhaps should be eventually extended to cover the
+%    whole set.
+%
+% \end{itemize}
 %
 %    \begin{macrocode}
 \DeclareFontSeriesChangeRule {bc}{b}{bc}{}		
@@ -64,8 +99,6 @@
 %    \end{macrocode}
 %    
 %    \begin{macrocode}
-\DeclareFontSeriesChangeRule {bx}{bx} {bx}  {b}		%<-----
-\DeclareFontSeriesChangeRule {bx}{b}  {b}   {bx}	%<-----
 \DeclareFontSeriesChangeRule {bx}{b}{bx}{}		
 \DeclareFontSeriesChangeRule {bx}{c}  {bc}  {bx}	%<-----
 \DeclareFontSeriesChangeRule {bx}{eb}{ebx}{}		
@@ -391,7 +424,7 @@
 \DeclareFontSeriesChangeRule {x}{?m}{m}{}	
 %    \end{macrocode}
 %
-% \emph{rules need to get completed!}
+% \emph{rules need to get completed/verified!}
 %
 %
 
@@ -460,18 +493,18 @@
     \else
        \ifcsname \f at encoding /\f at family /#2/\f at shape \endcsname
 %    \end{macrocode}
-%    If the alternate result exist we use that
+%    If the alternate result exist we use that and also issue a
+%    warning (or rather a log entry) that we didn't managed to change
+%    to the desired font.
 %    \begin{macrocode}
          \edef\f at series{#2}%
          \@font at shape@subst at warning
 %    \end{macrocode}
-%    If that doesn't exist either, then we use the requested series unmodified.
+%    If that doesn't exist either, then we use the requested series unmodified
+%    (again with a warning).
 %    \begin{macrocode}
        \else
          \edef\f at series{#3}%
-%    \end{macrocode}
-%    We issue a warning that we didn't managed to change to the desired font.
-%    \begin{macrocode}
          \@font at shape@subst at warning
        \fi
     \fi