I see. I think reading your initial comment I took issue with the hyperbole "crazy control-flow (monadic) magic is happening here". But yes it is a hidden cont

I see. I think reading your initial comment I took issue with the hyperbole "crazy control-flow (monadic) magic is happening here". But yes it is a hidden control flow, and taking in account hidden control flows is inherently more complicated (or at least has a steeper learning curve).