# Automatic camel case breaking

Based on my old question Push long words in a new line, I search for a possibility to allow linebreak before a capital character in camel case terms.

For example the term createUnspecifiedNodeErrorMarker can be break into create-Unspecified-Node-Error-Marker.

\documentclass{scrartcl}

\begin{document}
\section{Test}
And another example the show must go on, but we have too less text (\textbf{createUnspecifiedNodeWarningMarker} and
\end{document}

• Be (but only slightly) careful what you wish for. Compare: "StringRenderingEngine" with "String[space]RenderingEngine". If it splits in the wrong place you have ambiguity. Aug 10 '12 at 8:18
• You are right, I only want to use it in an seperate environment, not for the whole document. Aug 10 '12 at 8:48

TeX would linebreak (hyphenate) the camel case words, but perhaps not where you wish eg

cre-a-te-Un-spec-i-fiedNodeEr-ror-Marker


shows the default hyphenation points (using the default US English hyphenation)

It wasn't clear if you wanted hyphens at the break points. I have assumed not. If you do then change \penalty2 to \-.

This boxes the parts between capital letters so they don't break, and puts a small penalty before capitals so they can break.

As with anything using catcode changes (like \verb it will not work in the argument to another command)

\documentclass{scrartcl}

\showhyphens{createUnspecifiedNodeErrorMarker}

\makeatletter
\def\zzz{\leavevmode\begingroup
\let\ifcase\iftrue
\def\or##1{%
\catcode##1\active\uccode\~##1\uppercase{%
\def~{\egroup\penalty2\hbox\bgroup\string##1}}}%
\@Alph{}%
\@zzz}

\def\@zzz#1{\textbf{\hbox\bgroup#1\egroup}\endgroup}
\makeatother

\begin{document}
\section{Test}

And another example the show must go on, but we have too less text (\zzz{createUnspecifiedNodeWarningMarker} and
\end{document}

• Is there any possibility to use it within captions? Oct 17 '12 at 14:25
• it's a fragile command so \protect\zzz should do the right thing, oh apart from the catcode change part :( Oct 17 '12 at 14:32
• I don't understand what you mean with "oh apart from the catcode change part :(" Oct 20 '12 at 13:42
• But protect doesn't work with sections and so on, correct? Oct 20 '12 at 14:44
• If one loads microtype there is a side effect: ! Package microtype Error: protrusion list cmr-OT1' cannot load itself.. One can avoid it by calling the bold font before it is used in the code (e.g. \AtBeginDocument{{\bfseries}}) Nov 26 '15 at 14:27

An implementation in expl3 that also allows a (named) color as optional argument to \keyw:

\documentclass{article}
\usepackage{xcolor}
\usepackage{microtype}
\usepackage{xparse}

\ExplSyntaxOn
\NewDocumentCommand{\keyw}{O{.}m}
{
\textcolor{#1}{ \bfseries \cschulz_keyw:n { #2 } }
}

\cs_new_protected:Nn \cschulz_keyw:n
{
\tl_map_inline:nn { #1 }
{
% if the current char is uppercase, add a discretionary hyphen
\str_if_eq:eeT { ##1 } { \str_uppercase:n { ##1 } }
{ \- }
##1
}
}
\ExplSyntaxOff

\begin{document}

\section{Test}

And another example the show must go on, but we have too less
text (\keyw{createUnspecifiedNodeWarningMarker} sdjkle
\keyw{createUnspecifiedNodeErrorMarker}, sdjklashjksa