Naturality of the conditional and the recursion∗
José Luis Freire Nistal, Aguado F. Martín · International Journal of Computer Mathematics · 1990
In a class of categories, including E. Manes's assertional ones, the control structures if-then-else and repeat-until are modeled as natural transformations of suitable functors. This context show how the three basic pieces of any structured programming language (concatenation, conditional and recursion) share naturality.