[Tex/LaTex] testing for a documentclass option

class-optionsconditionals

I know that there are lots of similar question, but none of those have helped me so far – and I did google a lot. So my question is: I have a document class (emulateapj) which accepts a few options.

In my document, I want to have a conditional test which checks if some option (for example onecolumn) is set, and if so, to do a few things like changing font size or line separation.

Something like

\IfSubStr{@classoptionslist}{onecolumn}{true}{false}%

Just gives me always false.

Best Answer

The kernel provides \@ifclasswith:

\documentclass[onecolumn]{emulateapj}

\makeatletter
\@ifclasswith{emulateapj}{onecolumn}{\typeout{ONECOLUMN}}{\typeout{NO ONECOLUMN}}
\@ifclasswith{emulateapj}{revtex4}{\typeout{REVTEX4}}{\typeout{NO REVTEX4}}

\makeatother

The output on the terminal is

ONECOLUMN
NO REVTEX4

The \@ifclasswith command is only available before \begin{document}, so if you want to set up your own conditional you have to do it in the preamble:

\makeatletter
\newif\ifhbonecolumn
\@ifclasswith{emulateapj}{onecolumn}{\hbonecolumntrue}{\hbonecolumnfalse}
\makeatother

\newcommand{\foo}{\ifhbonecolumn fooone\else footwo\fi}

Related Solutions

[Tex/LaTex] How to conditionally execute something based on a documentclass option

Package and class options generally have meaning just for that particular class or package. The book class doesn't have an instructor option. If you're making your own class, based on book, then it is quite simple. It'd be something like

\newif\if@instructor
\@instructorfalse
\DeclareOption{instructor}{\@instructortrue}
\ProcessOptions\relax

Then you could use \if@instructor in the document (although you'd need to have used \makeatletter first, so maybe it's better to omit the @).

If you're not making your own class, then the easiest way would be to just have

\newif\if@instructor
\@instructortrue % or \@instructorfalse depending on which you want

in your preamble.

[Tex/LaTex] Testing for number

Here's a slightly flawed, but slightly more generic thing than you're asking for.

\documentclass{article}
\usepackage{etoolbox}
\makeatletter
\newcommand\ifnumber[1]{%
        \begingroup
        \edef\temp{#1}%
        \expandafter\ifstrempty\expandafter{\temp}
                {\endgroup\@secondoftwo}
                {\expandafter\ifnumber@i\temp\@nnil}%
}
\def\ifnumber@i#1#2\@nnil{%
        \if-#1%
                \ifstrempty{#2}
                        {\def\temp{X}}
                        {\def\temp{#2}}%
        \else
                \def\temp{#1#2}%
        \fi
        \afterassignment\ifnumhelper
        \count@0\temp\relax\@nnil
        \endgroup
}

\def\numrelax{\relax}%
\def\ifnumhelper#1\@nnil{%
        \def\temp{#1}%
        \ifx\temp\numrelax
                \aftergroup\@firstoftwo
        \else
                \aftergroup\@secondoftwo
        \fi
}
\makeatother

\newcommand\testnumber[1]{#1: \ifnumber{#1}{Number}{Not a number}\par}
\begin{document}
\def\foo{-55}
\testnumber{1234}
\testnumber{\foo}
\testnumber{-}
\testnumber{}
\testnumber{1}
\testnumber{1234abc}
\testnumber{abc1234}
\end{document}

It's slightly complicated by checking if the first token in the expansion of the argument is a -. Unfortunately, it does not work if the argument is a register. (It probably doesn't work in other cases too.)

But from the \ifnumber macro, you should easily be about to build what you want.

\newcommand\domorestuffifnumber[1]{\ifnumber{#1}{\emph{#1}}{#1}}

Best Answer

Related Solutions

[Tex/LaTex] How to conditionally execute something based on a documentclass option

[Tex/LaTex] Testing for number

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