I don't know if you are aware of that, but at the time Pascal started emerging, the exact same arguments were presented by foiks used to BASIC that having the a

I don't know if you are aware of that, but at the time Pascal started emerging, the exact same arguments were presented by foiks used to BASIC that having the ability to add your own "words" to the language would inevitably lead to a mess. Why didn't it happen? Because programmers overall are reasonable folks. So, yes, in theory, you can define a factorial function and call it "Not_a_Cat" (technically, it is true), but nobody does that. Similarly, giving the ability to define `X in Y..Z` makes code more readable if you use it right, not less.