If-else in Latex

Question

I want to have different headers/footers, depending on what "part" I have, which is defined in the "mPart" variable...

I'm using the following code to distinguish between the parts:

\newcommand{\PartEinleitung}{0}
\newcommand{\PartHauptteil}{1}
\newcommand{\PartAppendix}{2}
\newcommand{\mPart}{}
\newcommand{\setPart}[1]{\renewcommand{\mPart}{#1}}
\newcommand{\mWriter}{}
\newcommand{\setWriter}[1]{\renewcommand{\mWriter}{#1}}

\ifnum\mPart=\PartEinleitung
    \rofoot*{\small\color{gray} Seite \thepage~von \pageref{LastPageEinleitung}}
\fi
\ifnum\mPart=\PartHauptteil
        \rehead*{\headmark}
        \lehead*{\mWriter}
        \rofoot*{\small\color{gray} Seite \thepage~von \pageref{LastPageHauptteil}}
\fi

The error is:

Missing number, treated as zero. \ifnum\mPart=

Hope you can help me, thank you!

I think it should be \rehead*{\ifx\mPart\PartHauptteil\headmark\fi}. At the time you're trying to set those headers your variables don't have the intended contents. — Skillmon, Dec 03 '17 at 18:52
Don't use \ifnum in LaTeX; see the ifthen package or the etoolbox package. And I'm sure expl3 also offers constructs. — Martin Schröder, Dec 04 '17 at 15:50
@MartinSchröder Why no \ifnum in LaTeX? I use it all the time, in preference to the the ifthen package. — Steven B. Segletes, Dec 04 '17 at 15:52
@StevenB.Segletes: It's a primitive; you should use LaTeX constructs in LaTeX. — Martin Schröder, Dec 04 '17 at 16:37
@MartinSchröder I could agree with your sentiment if the if-then features were part of native LaTeX...but they are not---they are part of an external package (ifthen). Thus, it seems to me that, as created, Lamport's LaTeX envisions the use of TeX's comparison primitives. — Steven B. Segletes, Dec 04 '17 at 17:37
@StevenB.Segletes: That was Leslie, i.e. 30 years ago. One of the ideas for LaTeX3 is to make all TeX primitives inaccessible so one must use the LaTeX3 constructs instead. — Martin Schröder, Dec 04 '17 at 22:12

score 0 · Accepted Answer · answered Mar 06 '18 at 19:53

Here's how I solved it:

\usepackage{scrlayer-scrpage}
\automark*{chapter}
\automark*{section}
\setkomafont{pageheadfoot}{\sffamily}
\setkomafont{pagination}{}

\newcommand{\PartEinleitung}{
    \clearpairofpagestyles
    \KOMAoptions{footsepline=true, plainfootsepline=true}
    \ofoot*{\small\color{gray} Seite \thepage~von \pageref{LastPageEinleitung}}
}
\newcommand{\PartHauptteil}{
    \clearpairofpagestyles
    \KOMAoptions{headsepline=true, plainheadsepline=true}
    \ihead*{\headmark}
    \ohead*{\mWriter}
    \ofoot*{\small\color{gray} Seite \thepage~von \pageref{LastPageHauptteil}}
}
\newcommand{\PartAppendix}{
    \clearpairofpagestyles
    \KOMAoptions{headsepline=false, plainheadsepline=false}
    \ofoot*{\small\color{gray} Seite \thepage~von \pageref{LastPageAppendix}}
}

Instead of using if else, i just change the Header and Footer using a command.

If-else in Latex

1 Answers1