{Functional data structures in \TeX} {Julien Cretel} {Because \TeX\ lacks rich data structures, implementing even simple yet useful algorithms in it can be laborious. However, \TeX\ is, in many ways, remarkably similar to functional programming languages, which are often praised for their expressive power. Building on Alan Jeffrey's approach to embedding elements of the lambda calculus in \TeX\ (see Alan's \pkgname{lazylist} package), I plan to demonstrate how to implement and use richer data structures (such as binary search trees) in \TeX\ \& friends.}