[texhax] Making a condition in LaTeX (if..., then..., else)

[Martin Heller]

HRE skrev:

> If the Package "pack.sty" exists, then include it in the main document 
> .tex "\include{pack.sty }".
> Else, ignore it.

\IfFileExists{pack.sty}
   {\usepackage{pack}}
   {\message{Package pack.sty was not found.}}