Have you tried reading "Can programming be liberated from the von Neumann style?: a functional style and its algebra of programs" by Backus? https://dl.acm.org

Have you tried reading "Can programming be liberated from the von Neumann style?: a functional style and its algebra of programs" by Backus? https://dl.acm.org/doi/10.1145/359576.359579 https://dl.acm.org/doi/10.1145/359576.359579