Example usage of https://github.com/Yord/LaTeX-Lists.

example.tex

\documentclass{article}

\input{list}

\def\times#1#2{\newcount\int\int\numexpr#1*#2\relax\the\int}

\begin{document}

  \List[new]{numbers}{1,2,3,4,5,6,7,8,9}

  list: \numbers[items]

  head: \numbers[head]

  tail: \numbers[tail]

  \List[new]{doubles}{\numbers[map]{\times{2}}}

  doubles: \doubles[items]

\end{document}