On 14-05-20 08:58 AM, silvio wrote:
Only because we can't just execute an IO action and fill in the result. And this list doesn't even include examples where the programmer had to resort to making a pointless temp variable just to avoid using too many complicated functions.
I agree that requiring extra variable names to express data propagation is a problem. I disagree that any notation that goes like third_effect {first_effect} {second_effect} is a solution. I have written it to highlight the problem: the order of the effects is neither entirely left-to-right nor entirely right-to-left, but rather a haphazard "start somewhere in the middle, go right for a while, now suddenly jump back to the left". This is also my second biggest gripe with Lisp, Scheme, SML, Caml, every impure functional language. One thing the do-notation gets right is that I/O effect order is the simple top-to-bottom. The solution is to liberate programming from the plain text file. Draw a dataflow-like diagram. Arrange effect boxes in one order to indicate effect order. Draw lines or curves between them to indicate data propagation and/or parameter passing. Can programming be liberated from the plain text file?