flacards.cls and loop don't work together

Question

I try to automatise the construction of my flashcards. I try with \foreach (tikz) and \forloop (forloop package), it's not working. The error is in the two case:

! LaTeX Error: There's no line here to end.
See the LaTeX manual or LaTeX Companion for explanation.

The code :

\documentclass{flacards}

\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}

\usepackage[frenchb]{babel}

\usepackage{forloop} 

\begin{document}
\newcounter{ct}
\forloop{ct}{1}{\value{ct} < 11}{ 
  \card{\arabic{ct}}{}
}
\end{document}

Answer 1

You have to specify some text also in the second argument. (La)TeX needs to go into horizontal mode, otherwise the error will show.

Since \null doesn't activate horizontal mode, it's useless. So

\card{\arabic{ct}}{~}

or \card{\arabic{ct}}{\ } will work.

Answer 2

I have no idea what's going on in the \card macro (and unfortunately I don't have time to investigate it), but it seems that the empty second argument is the culprit. Interestingly enough, \card{\arabic{ct}}{\null} does not help (anyone has any idea why?), but \card{\arabic{ct}}{\ } does.

(And obviously the loop has nothing to do with that.)