通过Opam安装Ocamlbuild和Packages

Question

我正在尝试制作这段代码:

open Lwt;;
open Cohttp;;
(* a simple function to access the content of the response *)
let content = function
  | Some (_, body) -> Cohttp_lwt_unix.Body.string_of_body body


(* launch both requests in parallel *)
let t = Lwt_list.map_p Cohttp_lwt_unix.Client.get
  (List.map Uri.of_string
     [ "http://example.org/";
       "http://example2.org/" ])

(* maps the result through the content function *)
let t2 = t >>= Lwt_list.map_p content

(* launch the event loop *)
let v = Lwt_main.run t2

但是,当我跑

Ocamlbuild file.native

我得到了未绑定的模块错误.

这些模块是通过opam安装的,当我运行时

ocamlfind query lwt 
/home/chris/.opam/system/lib/lwt
ocamlfind query cohttp
/home/chris/.opam/system/lib/cohttp

如何让Ocamlbuild找到这两个包？

我试过了

Ocamlbuild -pkgs cohttp,lwt file.native 

它不起作用.它说了一些可能的扩展.我不认为这是问题所在.

如果有人能给我正确的代码来做到这一点,将不胜感激.谢谢!

Answer 1

Cohttp已更新,所以我已更正您的代码以使用最新版本:

open Lwt;;
open Cohttp;;
(* a simple function to access the content of the response *)
let content = function
| Some (_, body) -> Cohttp_lwt_body.string_of_body body
| None -> assert false


(* launch both requests in parallel *)
let t = Lwt_list.map_p Cohttp_lwt_unix.Client.get
(List.map Uri.of_string
    [ "http://google.com";
    "http://yahoo.com" ])

(* maps the result through the content function *)
let t2 = t >>= Lwt_list.map_p content

(* launch the event loop *)
let v = Lwt_main.run t2

你可以用

ocamlbuild -use-ocamlfind -pkgs cohttp.lwt file.native

几条评论:

1)您应该使用-use-ocamlfindwith ocamlbuild来使用opam(或任何其他已安装的ocaml库)

2)要使用cowt与lwt,你应该使用cohttp.lwt包.添加lwt也不是绝对必要的.