You do not need to school me about why "for" is not pure functional - as soon as you understand that it is syntactic sugar, you are fine; IO is also impure, so if you insisting in purity then the only option is Haskell.
If you want to be pedantic, in functional programming there is no such a thing as "return value", as there is no such a thing as statement, only expressions. And expressions always _have_ values, they do not _return_ them.
I agree that SML is better for teaching than OCaml no doubt about it.
I mean, it is pointless to continue this conversation; you did not use SML for a long time - I did use it last time last year, and I can attest, it is extremely impractical compared to any other FP language today.
I have personally obtained unmesurable amount of relevant info from twitter; lots of true experts in every area in real time. Blogs were more like reading a published magazine article - for something not time sensitive.
1. It was USSR, not Russia. For many who were USSR citizen till 1991, but neither ethnically or geographically Russians, this rubs very wrong way.
2. Aviation in the USSR was developing completely independent, and you can accuse USSR in stealing technology in many areas but certainly not in aviation.
You SML code is incorrect, shows that you actually never coded anything in SML. SML requires that "if" always contains "else" clause (which is the norm for many functional languages). And this kind of stuff which makes SML unnecessarily verbose (OCaml has for operators, single line let definitions that do not require you to make use val and fun for different type definitions etc.).
The thing with eyestrain, that it is extremely different to pinpoint what it causes for people with sensitive eye, so any alternative solution would work.
The most important factor is, obviously is the backlight, and not only being PWM or DC, but also the spectrum and "texture" of the light itself: a typical LCD has diffusers which may have different construction and cause serious issues for some people. Some may be sensitive to polarisation, some people are sensitive to how grainy is antiglare coating is etc.
A good number of people (me including) cannot tolerate backlight with blue at 450 nm, the more it is towards green the better. Some cannot tolerate KSF phosphor in the wide gamut backlights (I am perfetcly fine with it), and love quantum dots.
It is a serious problem, but using the ambient light for the backlight would make experimenting the backlight a super easy task, so yeah, this monitor is a great idea.
This crude advice, which is not always effiecient. I have sensitive eyes, and many monitors cause issues even when they are set _at_ _zero_ brightness. The both feel too dim and too bright simultaneously. Even a single white letter on a black bacground would cause bad eyestrain on a "bad" monitor. Luckily I have found models which do not cause issues and am using them.
It is a typical advice which is efficient but flawed. All software methods to change color temperature suffer from two problems: they kill contrast (already low for IPS), and they kill color calibration. It also cannot change the backlight spectrum in the blue area. Proper, good backlight won't strain your eyes, when run at normal 6500K temperature,as it has blue peaks shifted.