A few of my college courses used OCaml, and it had lots of conventions like this that I found somewhat odd. If I remember correctly, exceptions (which were not used that often from what I could tell due to preferences for handling errors in a more algebraic manner) are named with casing like `Not_found`, which I don't even know the name for (maybe "capitalized snake-case?), I assume to try to make them resemble the capitalization scheme that sentences use. I also remember finding it quite strange to read types annotated with a space before the colon (e.g. `let x : int in`); a friend told me that this was due to OCaml's authors being French, which unlike English puts spaces in front of colons in prose. Combined with the fact that we were taught only a subset of the language (we never once learned how to use the object system for which the "O" was put in OCaml), and we were processed provided with pre-written build files for projects and not taught much how how to use the build tools, writing OCaml always felt somewhat surreal for me. Overall though, I did learn a lot from those classes, and I think it was a good choice for teaching the concepts the courses were intended to cover (especially the compilers course, which in retrospect I would have found much more tedious if course was taught in C or Java or something).
> I also remember finding it quite strange to read types annotated with a space before the colon (e.g. `let x : int in`); a friend told me that this was due to OCaml's authors being French, which unlike English puts spaces in front of colons in prose.
Maybe, but I find it more likely that they just copied math notation. In mathematics (broadly, not just theoretical CS, also analysis), the type of something is indicated with an infix `:`, like `f : A -> B` is a function from A to B. This colon conventionally has equal spacing on both sides, like a regular infix operator.
That's possible as well. I have no idea about the accuracy of my friend's claim, which is why I relayed it as hearsay rather than stating it as a fact I was sure about.
OCaml exception constructors are just term constructors in the open sum type `exn`. In OCaml, to distinguish constructors from bound variables, constructors must begin with a capital letter. Thus `let Foo = 4;;` is an error.
