4.1 Defining Macros in L^aT_eX

Defining macros in L^aT_eX using plasT_eX is no different than the way you would normally define you macros; however, there is a trick that you can use to improve you macros for plasT_eX, if needed. While plasT_eX can handle fairly complicated macros, some macros might do things that don’t make sense in the context of a plasT_eX document, or they might just be too complicated for the plasT_eX engine to handle. In cases such as these, you can use the \ifplastex construct. As you may know in T_eX, you can define your own \if commands using the \newif primitive. There is an \if command called \ifplastex built into the plasT_eX engine that is always set to true. In you document, you can define this command and set it to false (as far as L^aT_eX is concerned) as follows.

\newif\ifplastex
\plastexfalse

Now you can surround the portions of your macros that plasT_eX has trouble with, or even write alternative versions of the macro for L^aT_eX and plasT_eX. Here is an example.

\newcommand{\foo}[1]{
    \ifplastex\else\vspace*{0.25in}\fi
    \textbf{\Large{#1}}
    \ifplastex\else\vspace*{1in}\fi
}

\ifplastex
    \newenvironment{coolbox}{}{}
\else
    \newenvironment{coolbox}
        {fbox\bgroup\begin{minipage}{5in}}
        {\end{minipage}\egroup}
\fi