This is a serie of reflections on the presentation of Runar Branson Specifically, in the 39:30 he mention side effects as one of the main causes of the lack of composability. Most of the time we need the effects arranged in a different way than the one that forces the composition. For the example that he mentions: choose coffe, pay, serve, we can sustitute the one whose effect we want to reorder (pay) by one non-effectful, (add-to-cart) so that we can make many selections and pay at the end. What we do is to keep in the cart state the items selected.
But there are other reasons why side effects can prevent composition: threading, blocking for wathever reasons: communications, semaphores, callbacks, concurrency, loops waiting for some conditions... These are considered as lost cases for composition and not even mentioned. But transient demonstrates that this is not the case, that it is possible t