Are there any ways to do control flow depending on the compilation method?

Question

I would like to do something like

\if{\pdflatex}{
   \includepdf{file.pdf}
}

\if{\latex}{
  \epsfig{file.eps}
}

Maybe this isn't the best example, but do control-flow solutions exist in LaTeX to let us do something depending on how we compile?

Answer 1

The ifpdf package.

Although for your specific example of wanting to include graphics.eps or graphics.pdf it's better to \usepackage{graphicx} and not specify an extension, i.e. \includegraphics{graphics}. See this FAQ answer.