# How to make sections into sentence case

I would like my sections (and potentially subsections) to be in "sentencecase" no matter how I type them. I am happy with the way the \MakeSentenceCase macro from the biblatex package converts text with arbitrary capitalization into sentencecase. I am having difficulty integrating this into the \section macro.

My first attempt was to redefine \section to be

\renewcommand{\section}{\@startsection{section}{1}{\z@}{-3.5ex \@plus -1ex \@minus -.2ex}{2.3ex \@plus.2ex}{\normalfont\Large\bfseries\MakeSentenceCase}}


but this fails because the first token (or something like that) to \MakeSentenceCase is not the first token of the text of my section heading, but rather related to the numbering and indenting. The following method works

\documentclass{article}

\usepackage{etoolbox}
\usepackage[backend=biber]{biblatex}

\makeatletter
\let\sectionOrig\section
\renewcommand{\section}{\@ifstar{\@sectionStar}{\@sectionNoStar}}%
\newcommand{\@sectionNoStar}[2][\relax]{\ifdefstring{\relax}{#1}{%
\sectionOrig{\MakeSentenceCase{#2}}%
}{%
\sectionOrig[#1]{\MakeSentenceCase{#2}}%
}}
\newcommand{\@sectionStar}[1]{\sectionOrig*{\MakeSentenceCase{#1}}}%
\makeatother

\begin{document}
\section{sections SHOULD BE IN {SENTENCECASE}}
\end{document}


by completely redefining the \section command. I have tried to take care of the starred and unstarred forms and optional arguments, but I am worried that this approach is going to cause problems someplace else.

I guess I have 3 questions. First, is it reasonable to expect LaTeX to automatically handle the capitalization of sections. Second, is my approach reasonable. Third, is there a better approach (or an already existing package).

-
Sorry, but it's not reasonable to expect LaTeX knows English (or any other language). –  egreg Jun 21 '13 at 16:49
@egreg "to expect LaTeX to know the English (or any other) language" ? ;-) [I am not sure ;-) -- will presumably soon delete this comment for fear of bringing shame on me... ] –  jfbu Jun 21 '13 at 19:52
@jfbu In this case, "expect LaTeX knows" is short for "expect that LaTeX knows". The word "that" can often be dropped. Your version is correct too. –  John Wickerson Jun 22 '13 at 7:36
@JohnWickerson sigh of relief... thanks! –  jfbu Jun 22 '13 at 8:10
@jfbu (shame shame shame—learn Italian ;)) Also, I don't see this as unreasonable as it is asked—but I would counter-ask (?) if this is what you really want; if any acronyms appear in your sections, they may be downcased (depending on how \MakeSentenceCase handles groups). –  Sean Allred Jul 28 '13 at 20:57
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This is easy using the titlesec package. With the explicit option (p. 8, sec. 3.7), we can use an (I think) arbitrary transformation on the sectioning title stored as #1. With this knowledge, the rest becomes a piece of cake:

\documentclass[twocolumn]{article} % two-column used to get everything onto one page
\usepackage{biblatex}

\usepackage[explicit]{titlesec} % note the explicit option

\titleformat{\section} % The normal, unstarred version
{\Large\bfseries}{}{2ex}
{\thesection. \MakeSentenceCase{#1}}

\titleformat{name=\section,numberless} % The starred version; note the numberless key
{\Large\bfseries}{}{2ex}
{\MakeSentenceCase{#1}}

\usepackage{mwe}
\begin{document}
\section{I am a Section}
\lipsum[1]
\section{I am An Other section}
\lipsum[2]
\section*{I am an UnNumBeReD section with {ACRO}-nyms}
\lipsum[3]
\section{I am a Section}
\lipsum[4]
\section{I am An Other section}
\lipsum[5]
\section{More {ACR}-o-{NYM}s!}
\end{document}


(Note that this solution can be easily applied to the other sectioning commands by just replacing \section and \thesection appropriately.)

• Your approach is reasonable if it works well, but it is usually better to build upon an existing package (e.g. titlesec) for more functionality. (For example, if you had written your own \MakeSentenceCase, that may have been a bit too much work—a lot of code means a lot of room for small errors.)