You have to be reasonable about the scale. A 4/5 in English by your standards would also imply a deep understanding of root languages, old English, literature etc...
Becoming "fluent" in a programming language is vastly different from becoming "fluent" in a natural language. I hate when people make that comparison. How often does one ask for the etymology of the "if" statement and to what extent is such an understanding required for programming language mastery?
Actually, I think knowing the history and theory behind a language (as appropriate) is very helpful.
Particularly, if you're using a language like Haskell or Ocaml, it helps to have at least a vague idea of what a functor actually is and where the idea comes from. (I actually only realized that functors were actually similar ideas in both languages a couple days back.)
On the other hand, if you're using a language like JavaScript, understanding the history (especially the languages that influenced it) makes understanding some of the "quirks" much simpler. When you see the influence of Scheme, the scoping suddenly makes much more sense, for example.
So, over all, I think understanding the background of a language really helps for complete mastery.
> Particularly, if you're using a language like Haskell or Ocaml, it helps to have at least a vague idea of what a functor actually is and where the idea comes from. (I actually only realized that functors were actually similar ideas in both languages a couple days back.)
I could not agree more! Understanding the significance of particular keywords is quite important when failing to do so will affect your ability to successfully use the language. I distinguish that from my argument, which I premised on such knowledge not affecting one's ability to successfully use the language.
If she would put 3/5 (like you imply) I would think that she as B1 level or something like that. She is not native. If she was a native the scale would be different.
