[dboreham]

Interesting thread. Although most of the comments are "you're holding it wrong", I think the author brings up good points, which are roughly along the lines of : the FP language tutorials don't tell you how to write real programs. Now, granted the problems cited will show up at some level of scale in non-FP programming -- you can't just rummage around in some huge nested data structure inside a C++ server application for example because you'll end up holding dangling pointers among other things. However, perhaps you can get much further with non-FP languages by following the basic tutorials.

Also interesting to note that modern UI application frameworks such as React/Redux don't mutate state in-place. They tend to generate some kind of mutation object that is "played" against the in-memory stored application state. Probably similar to the FP-kosher solutions suggested here.