ocaml

问题 I defined a custom equality operator (the definition is not really important so I will insert dummy stuff): let ( ~=~ ) a b = true If I try to use it infix: if a ~=~ b then 1 else 2 I get the following error: This expression is not a function; it cannot be applied . I can fix this either by renaming the operator from ~=~ to =~ or by calling it as a function: if (~=~) a b then 1 else 2 . This seems that is a general problem with operators that start with ~ . My question is why I can't use such

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed last year . Know of an OCAML/CAML IDE? Especially one that runs on Linux? 回答1: Emacs in Caml mode, or Tuareg mode, or TypeRex mode. TypeRex adds auto-completion to Taureg in emacs - a really nice feature for people who prefer the more graphical IDE's. 回答2: There is Camelia. You can also integrate OCaml into Eclipse. Also in

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 3 years ago . I want to advertise OCaml to beginners, and I am looking for good tutorials in English; not that you have only heard of, but that you have actually tried and found useful... 回答1: I quite like the book Developing Applications With Objective Caml -- I guess the title should be updated to mirror the 'OCaml' naming

问题 I'm trying to get an ocaml environment set up, and I've followed the instructions from appendix A of the Real World Ocaml beta. I set up opam, and installed a version of ocaml with the command $ opam switch 4.01.0dev+trunk which passed fine. I then did an $ eval `opam config env` to pull in the changes. I'm running the correct top level, as $ which ocaml outputs /home/bryan/.opam/4.01.0dev+trunk/bin/ocaml I installed the Core package from Jane street, with the command $ opam install core Both

问题 I wrote a OCaml program for union find algorithm. This algorithm I wrote is not optimal and is the simplest version. I put my OCaml code here because I am not sure whether this code is good enough or not (despite of the algorithm itself) , although this code can run without errors. This is the first time I wrote a complete working thing after I started to learn OCaml, so please help me by reviewing it. Useful suggestions will help me improving my OCaml skills. Thanks type union_find = {id_ary

问题 It is not hard to shuffle an array in O(n), with in place swapping, How to do it for list in OCaml, with O(n)? Requirement: No array or in place usage Consider this as an interview question 回答1: Lists are immutable, and there's often a log n price to pay for working with immutable data. If you're willing to pay this cost, there's an obvious n log n approach: tag each list element with a random value, sort based on random value, remove random values. This is the way I shuffle lists in my

问题 I can't use print_endline because it requires a string, and I don't (think) I have any way to convert my very simple user-defined datatypes to strings. How can I check the values of variables of these datatypes? 回答1: In many cases, it's not hard to write your own string_of_ conversion routine. That's a simple alternative that doesn't require any extra libraries or non-standard OCaml extensions. For the courses I teach that use OCaml, this is often the simplest mechanism for students. (It

问题 I've often read that exceptions are somewhat slow and should be avoided if performance is an issue (for instance, in Java, F#, etc). Does that apply to common OCaml functions such as Hashtbl.find , which return exceptions for elements not found? In particular, if I want my application to be efficient, should I always test element membership using, for instance, Hashtable.mem before calling Hashtbl.find ? Or would the extra comparison of the mem function negatively impact performance? 回答1:

问题 Is there a function for integer exponentiation in OCaml? ** is only for floats. Although it seems to be mostly accurate, isn't there a possibility of precision errors, something like 2. ** 3. = 8. returning false sometimes? Is there a library function for integer exponentiation? I could write my own, but efficiency concerns come into that, and also I'd be surprised if there isn't such a function already. 回答1: Regarding the floating-point part of your question: OCaml calls the underlying

问题 Is it possible to implement a tail recursive version of the quick sort algorithm (via the continuation pattern)? And if it is, how would one implement it? Normal (not optimized) version: let rec quicksort list = match list with | [] -> [] | element::[] -> [element] | pivot::rest -> let ``elements smaller than pivot``, ``elements larger or equal to pivot``= rest |> List.partition(fun element -> element < pivot) quicksort ``elements smaller than pivot`` @ [pivot] @ quicksort ``elements larger