单独编译OCaml模块 [英] Separate compilation of OCaml modules

问题描述

我已阅读此问题以及其他内容， 但是我的编译问题没有解决.

I have read this question and others, but my compile problem is unsolved.

我正在使用这些文件测试单独的编译:

I am testing separate compilation with these files:

testmoda.ml

testmoda.ml

module Testmoda = struct
  let greeter () = print_endline "greetings from module a"
end

testmodb.ml

testmodb.ml

module Testmodb = struct
  let dogreet () = print_endline "Modul B:"; Testmoda.greeter ()
end

testmod.ml

testmod.ml

let main () =
  print_endline "Calling modules now...";
  Testmoda.greeter ();
  Testmodb.dogreet (); 
  print_endline "End."
;;
let _ = main ()

现在我生成.mli文件

Now I generate the .mli file

ocamlc -c -i testmoda.ml >testmoda.mli

那里是testmoda.cmi.

and the testmoda.cmi is there.

下一步，我创建无错误的.c​​mo文件:

Next I create the .cmo file without errors:

ocamlc -c testmoda.ml

很好，对testmodb.ml也是如此:

Fine, so do the same with testmodb.ml:

strobel@s131-amd:~/Ocaml/ml/testmod> ocamlc -c -i testmodb.ml >testmodb.mli
File "testmodb.ml", line 3, characters 45-61:
Error: Unbound value Testmoda.greeter

另一种尝试:

strobel@s131-amd:~/Ocaml/ml/testmod> ocamlc -c testmoda.cmo testmodb.ml
File "testmodb.ml", line 3, characters 45-61:
Error: Unbound value Testmoda.greeter

其他组合也失败了.

如何编译testmodb.ml和testmod.ml?这应该很容易-没有ocamlbuild/omake/ 我认为是绿洲.

How do I compile testmodb.ml and testmod.ml? This should be easy - without ocamlbuild / omake / oasis, I think.

排除文件中的语法错误， 如果我将它们组合在一起到一个文件(之间有所需的空间)，它将进行编译 并完美执行.

Syntax errors in the files are excluded, if I cat them together to one file (with the required space between) it compiles and executes perfectly.

推荐答案

OCaml在每个源文件的顶层为您提供了免费的模块.因此，您的第一个模块实际上被命名为Testmoda.Testmoda，该函数被命名为Testmoda.Testmoda.greeter，依此类推.如果您的文件仅包含函数定义，那么效果会更好.

OCaml gives you a module for free at the top level of each source file. So your first module is actually named Testmoda.Testmoda, the function is named Testmoda.Testmoda.greeter, and so on. Things will work better if your files just contain the function definitions.

作为补充，如果您要使用ocamlc -i生成的界面，则实际上不需要mli文件.没有mli文件的接口与ocamlc -i生成的接口相同.如果您不希望使用默认界面，则使用ocamlc -i可以为您的mli文件提供一个很好的起点.但是对于这样一个简单的示例，它只会使事情看上去比实际情况复杂得多(恕我直言).

As a side comment, if you're going to use the interface generated by ocamlc -i, you really don't need mli files. The interface in the absence of an mli file is the same as the one generated by ocamlc -i. If you don't want the default interface, using ocamlc -i gives a good starting point for your mli file. But for a simple example like this, it just makes things look a lot more complicated than they really are (IMHO).

如果您按照我的描述修改了文件(删除了多余的模块声明)，则可以按如下所述从头开始编译并运行:

If you modify your files as I describe (remove extra module declarations), you can compile and run from scratch as follows:

$ ls
testmod.ml  testmoda.ml testmodb.ml
$ cat testmoda.ml
let greeter () = print_endline "greetings from module a"
$ cat testmodb.ml
let dogreet () = print_endline "Modul B:"; Testmoda.greeter ()
$ ocamlc -o testmod testmoda.ml testmodb.ml testmod.ml
$ ./testmod
Calling modules now...
greetings from module a
Modul B:
greetings from module a
End.

如果已经使用ocamlc -c file.ml编译了文件，则可以在上述命令中将.ml替换为.cmo.即使所有文件名都是.cmo文件，此方法也有效；在这种情况下，ocamlc只是为您将它们链接在一起.

If you have already compiled a file (with ocamlc -c file.ml) you can replace .ml with .cmo in the above command. This works even if all the filenames are .cmo files; in that case ocamlc just links them together for you.

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