ocaml

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 4 years ago . The OCaml download page is announcing that there is four Windows ports available: Cygwin, Mingw, native Win32, and native Win64. However the latest one is in fact not available and must be compiled from sources only. Given that the Windows/x86_64 port has been done since a

问题 I'm trying to implement my own list module as follows : type 'a my_list = | Item of ('a * 'a my_list) | Empty I've already implemented several functions and am now trying to create a list reversing function for my module which would look like this : let rec rev = function | Empty -> (*return reversed list*) | Item(i, remnant) -> (*recursive call to rev*) Moreover, I'm not supposed to use list operators such as '::', '[]' and '@'. Edit, what I tried : let rec rev_append l1 l2 = match l1 with |

问题 I'm trying to implement my own list module as follows : type 'a my_list = | Item of ('a * 'a my_list) | Empty I've already implemented several functions and am now trying to create a list reversing function for my module which would look like this : let rec rev = function | Empty -> (*return reversed list*) | Item(i, remnant) -> (*recursive call to rev*) Moreover, I'm not supposed to use list operators such as '::', '[]' and '@'. Edit, what I tried : let rec rev_append l1 l2 = match l1 with |

问题 Ok, I have written a binary search tree in OCaml. type 'a bstree = |Node of 'a * 'a bstree * 'a bstree |Leaf let rec insert x = function |Leaf -> Node (x, Leaf, Leaf) |Node (y, left, right) as node -> if x < y then Node (y, insert x left, right) else if x > y then Node (y, left, insert x right) else node The above code was said to be good in The right way to use a data structure in OCaml However, I found a problem. This insert will only work when building a bst from a list in one go, such as

问题 I'm following this blog post: http://semantic-domain.blogspot.com/2012/12/total-functional-programming-in-partial.html It shows a small OCaml compiler program for System T (a simple total functional language). The entire pipeline takes OCaml syntax (via Camlp4 metaprogramming) transforms them to OCaml AST that is translated to SystemT Lambda Calculus (see: module Term ) and then finally SystemT Combinator Calculus (see: module Goedel ). The final step is also wrapped with OCaml

问题 I often need to match a tuple of values that should have the same constructor. The catchall _,_ always winds-up at the end. This of course is fragile, any additional constructor added to the type will compile perfectly fine. My current thoughts are to have matches that connect the first but not second argument. But, is there any other options? For example, type data = | States of int array | Chars of (char list) array let median a b = match a,b with | States xs, States ys -> assert( (Array

问题 I'm learning. This is something I found strange: let test_treeways x = match x with | _ when x < 0 -> -1 | _ when x > 0 -> 1 | _ -> 0;; If I then call it like this: test_threeways -10;; I will get type mismatch error (because, as far as I understand, it interprets unary minus as if it was partial function application, so it considers the type of the expression to be int -> int . However, this: test_threeways (-10);; acts as expected (though this actually calculates the value, as I could

问题 Rust has a linear type system. Is there any (good) way to simulate this in OCaml? E.g., when using ocaml-lua, I want to make sure some functions are called only when Lua is in a specific state (table on top of stack, etc). Edti : Here's a recent paper about resource polymorphism relevant to the question: https://arxiv.org/abs/1803.02796 回答1: As suggested by John Rivers, you can use a monadic style to represent "effectful" computation in a way that hides the linear constraint in the effect API

问题 I'm trying to parse a grammar in ocamlyacc (pretty much the same as regular yacc) which supports function application with no operators (like in Ocaml or Haskell), and the normal assortment of binary and unary operators. I'm getting a reduce/reduce conflict with the '-' operator, which can be used both for subtraction and negation. Here is a sample of the grammar I'm using: %token <int> INT %token <string> ID %token MINUS %start expr %type <expr> expr %nonassoc INT ID %left MINUS %left APPLY

问题 I'm trying to parse a grammar in ocamlyacc (pretty much the same as regular yacc) which supports function application with no operators (like in Ocaml or Haskell), and the normal assortment of binary and unary operators. I'm getting a reduce/reduce conflict with the '-' operator, which can be used both for subtraction and negation. Here is a sample of the grammar I'm using: %token <int> INT %token <string> ID %token MINUS %start expr %type <expr> expr %nonassoc INT ID %left MINUS %left APPLY