[Tex/LaTex] breqn package incompatibility

breqnincompatibility

Edit: For clarity about what this post is asking, I have placed the specific questions at the beginning of the post.

I would like to understand the technical details of the incompatibilities of breqn.sty (v0.98a) with other packages in TexLive2009. These incompatibilities appear to vanish in subsequent editions of TexLive, and I would like to know what changes have been made to the remediate the incompatibilities? Lastly, what does the obscure and unhelpful error message cited below signify?

Background to contextualize the above questions:

On an amd64 linux system running TexLive 2009, I find that the package breqn (v0.98a) must be the last package loaded, otherwise it interferes with loading of certain other packages, in particular listings (v1.4), xcolor (v2.11), and graphicx (v1.0f).

Below, I include an example document that generates an error.

\documentclass{article}
\usepackage{breqn}
\usepackage{listings}
\begin{document}
Null.
\end{document}

The output (including the error message) produced upon compilation of this document with pdflatex is:

This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009/Debian)
entering extended mode
(./breqn.tex
LaTeX2e <2009/09/24>
Babel <v3.8l> and hyphenation patterns for english, usenglishmax, dumylang, nohyphenation, loaded.
(/usr/share/texmf-texlive/tex/latex/base/article.cls
Document Class: article 2007/10/19 v1.4h Standard LaTeX document class
(/usr/share/texmf-texlive/tex/latex/base/size10.clo))
(/usr/share/texmf-texlive/tex/latex/mh/breqn.sty
(/usr/share/texmf-texlive/tex/latex/mh/flexisym.sty
(/usr/share/texmf-texlive/tex/latex/mh/cmbase.sym)
(/usr/share/texmf-texlive/tex/latex/mh/mathstyle.sty))
(/usr/share/texmf-texlive/tex/latex/graphics/keyval.sty)
(/usr/share/texmf-texlive/tex/latex/tools/calc.sty))
(/usr/share/texmf-texlive/tex/latex/listings/listings.sty
! Missing number, treated as zero.
<to be read again> 
                   ^
l.44 \lst@InputCatcodes

?

When I compile the same code on a mac osx 10.6 system running MacTeX-2011, the code compiles without error, regardless of when breqn.sty is loaded.

The following excerpt from the breqn manual (Section 6.1) does specify that such incompatibilities may occur:

As it pushes the envelope of what is possible within the context of LaTeX 2ε, the breqn package will tend to break other packages when used in combination with them, or to fail itself, when there are any areas of internal overlap; successful use may in some cases depend on package loading order.

Best Answer

The breqn package has undergone a thorough revision from the version in TeX Live 2009 to the one in TeX Live 2010 (which is identical to the version in TeX Live 2011).

The error is triggered by the fact that flexisym.sty changes the category code of ^ too early, so that a syntax such as \catcode`\^^@ which is needed by listings is not legal any more: for it to work the ^ must have category code 7 and not 12.

The newer versions of the packages breqn and flexisym delay the category code change at begin document, so packages can still use the ^^ notation. This was clearly a misfeature in breqn and flexisym, but explains why loading breqn last might solve the problem.

Related Solutions

[Tex/LaTex] How to get only one symbol from a symbol package

No, there is no general procedure. One has to look into the package code and some knowledge of the terminal can be helpful; but one can always open the package file with an editor.

Let's see for \WritingHand that the Comprehensive List tells you it is from marvosym.sty.

First of all, we need to identify how the font is known to LaTeX. In these cases, rather than opening the file in an editor, I use less:

less $(kpsewhich marvosym.sty)

because kpsewhich is the utility that's used internally by the TeX programs to find a file. The first lines in the file are

\ProvidesPackage{marvosym}
  [2011/07/20 v2.2 Martin Vogel's Symbols font definitions]
\newcommand{\mvs}{\fontfamily{mvs}\fontencoding{U}%
\fontseries{m}\fontshape{n}\selectfont}

Good. We know how to load the font. The code is not the best possible, because

\newcommand{\mvs}{\usefont{U}{mvs}{m}{n}}

would be a cleaner call, although they're equivalent. The encoding U is “unspecified“ or “unknown”, which means that LaTeX won't try any of its tricks to adapt commands to the current encoding. It is a standard encoding, so there's no need to declare it beforehand. Any time we need a glyph from the font, we can say

\usefont{U}{mvs}{m}{n}

in a group. Now we look for \WritingHand and we find it on line 80:

\newcommand\WritingHand{\mvchr{98}}     \let\Writinghand\WritingHand

the second part is just an alias. What's \mvchr? It's on line 5

\newcommand{\mvchr}[1]{{\mvs\char#1}}

but it's again poor LaTeX programming, because \symbol{#1} would be better.

So we have all the necessary bits in order to accomplish our task:

\newcommand{\WritingHand}{{\usefont{U}{mvs}{m}{n}\symbol{98}}}

will work without loading any package. If you plan to use \WritingHand in moving arguments (sectional titles or captions, for instance), it may be better to use \DeclareRobustCommand instead of \newcommand, otherwise in the .aux file you would find

{\fontencoding  {#1}\fontfamily  {#2}\fontseries  {#3}\fontshape  {#4}\selectfont  \ignorespaces \char 98\relax }

instead of a simple \WritingHand. Not much of a problem, but possibly annoying.

Suppose instead you want to use the glyph

enter image description here

that is available in the STIX font package. Looking at the documentation, we find it at position octal 204 (decimal 132) in the font stix-extra1 (font table on page 43).

As before, we look in stix.sty, but we don't find extra inside it. Turn back to the documentation: on page 2 we find indeed

There are also three fonts containing extra miscellaneous symbols, stix-extra1, stix-extra2 and stix-extra3, provided as TFM and PFB files without support from the macro package.

This seems a problem, but indeed it isn't. We can proceed almost as before, just adding the necessary infrastructure

\DeclareFontFamily{U}{stixextrai}{}
\DeclareFontShape{U}{stixextrai}{m}{n}
 { <-> stix-extra1 }{}

\newcommand{\WolframSym}{{\usefont{U}{stixextrai}{m}{n}\symbol{132}}}

The same caveat as before for \DeclareRobustCommand applies. The family name stixextrai is arbitrary. Example document:

\documentclass{article}

\DeclareFontFamily{U}{stixextrai}{}
\DeclareFontShape{U}{stixextrai}{m}{n}
 { <-> stix-extra1 }{}

\newcommand{\WolframSym}{{\usefont{U}{stixextrai}{m}{n}\symbol{132}}}

\begin{document}
\WolframSym
\end{document}

which is how I produced the image above.

[Tex/LaTex] Using hepparticles with breqn

A really minimal example actually doesn't require hepparticle:

\documentclass{article}
\usepackage{breqn}

\begin{document}

$\mathit{\nu}$

\end{document}

If you try it, you'll see the same strange symbol you get with your code, which is the ring accent from the italic font. The fact is that eventually \HepParticle{\nu}{e}{} wants to do

\mathit{\nu}

Such a command would simply produce a standard nu letter, with the default LaTeX setting; hepparticles uses this to italicize letters, but not using math italic.

However, breqn (or, better, flexisym) changes the meaning of \nu so that it gives essentially a random result if in the argument to \mathit. For very strange reasons, Greek letters are redeclared by flexisym to be of type 7 instead of 0, so they obey the current math group.

You can fix \nu, but you'll have similar problems with other characters, probably. Look in cmbase.sym and copy the offending definitions changing Var into Ord as I did for \nu.

\documentclass{article}
\usepackage{hepparticles}
\usepackage{breqn}

% Fix the wrong assignment to \nu
\DeclareFlexSymbol{\nu}{Ord}{greek}{17}

\begin{document}
Electron neutrino \HepParticle{\nu}{e}{}.

Electron anti-neutrino \HepAntiParticle{\nu}{e}{}.
\end{document}

enter image description here

This is clearly a bug of flexisym; but I usually recommend against using breqn in the first place. A nice idea which simply doesn't work.

On the other hand, it seems that at least this example works with unicode-math. Compile with XeLaTeX:

\documentclass{article}
\usepackage{hepparticles}
\usepackage{breqn}
\usepackage{unicode-math}

\begin{document}
Electron neutrino \HepParticle{\nu}{e}{}.

Electron anti-neutrino \HepAntiParticle{\nu}{e}{}.
\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] How to get only one symbol from a symbol package

[Tex/LaTex] Using hepparticles with breqn

Related Question