[macros] Restore sentence spacing after \tcode

TeX treats a word ending with an uppercase letter as an abbreviation.
This makes the space after `\tcode{T}.` result in regular interword
spacing. To restore proper (wider) sentence spacing, this commit
appends `\@` to the `\tcode` command. The insertion of `\@` happens
only during normal typesetting; it is suppressed when writing the .idx
file and when generating bookmarks.

Author: morinmorin

source/macros.tex

@@ -235,14 +235,19 @@
 %%--------------------------------------------------
 \newcommand{\CodeStyle}{\ttfamily}
 \newcommand{\CodeStylex}[1]{\texttt{\protect\frenchspacing #1}}
+\makeatletter
+% Append `\@` to restore proper sentence spacing in text mode. This insertion
+% happens only during normal typesetting; it is suppressed for .idx generation.
+\newcommand{\CodeStylexGuarded}[1]{\CodeStylex{#1\ifmmode\else\ifx\protect\@typeset@protect\@\fi\fi}}
+\makeatother
 
 \definecolor{grammar-gray}{gray}{0.2}
 
 % General grammar style
 \newcommand{\GrammarStylex}[1]{\textcolor{grammar-gray}{\textsf{\textit{#1}}}}
 
 % Code and definitions embedded in text.
-\newcommand{\tcode}[1]{\CodeStylex{#1}}
+\newcommand{\tcode}[1]{\CodeStylexGuarded{#1}}
 \newcommand{\term}[1]{\textit{#1}}
 \newcommand{\gterm}[1]{\GrammarStylex{#1}}
 \newcommand{\fakegrammarterm}[1]{\gterm{#1}}
@@ -592,7 +597,7 @@
 \lstset{escapechar=@, aboveskip=\parskip, belowskip=0pt,
         midpenalty=500, endpenalty=-50,
         emptylinepenalty=-250, semicolonpenalty=0,upquote=true}%
-\renewcommand{\tcode}[1]{\textup{\CodeStylex{##1}}}
+\renewcommand{\tcode}[1]{\textup{\CodeStylexGuarded{##1}}}
 \renewcommand{\term}[1]{\textit{##1}}%
 \renewcommand{\grammarterm}[1]{\gterm{##1}}%
 }
@@ -650,7 +655,7 @@
  belowskip=0ex	% leave this alone: it keeps these things out of the
 				% footnote area
  }%
- \renewcommand{\tcode}[1]{\textup{\CodeStylex{##1}}}
+ \renewcommand{\tcode}[1]{\textup{\CodeStylexGuarded{##1}}}
 }
 {
 }