ocaml - 制作兼容的ocaml，camlp4，ppx，node，js_of_ocaml，ocamlbuild

安装npm和node后，用js_of_ocaml编译OCaml文件会出错，因此我做了opam switch reinstall system：

:testweb $ opam switch reinstall system
Your system compiler has been changed. Do you want to upgrade your OPAM installation ? [Y/n] y

=-=- Upgrading system -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  🐫
[WARNING] base-ocamlbuild.base is not available because it requires OCaml >= 3.10 & < 4.03. Skipping.
[WARNING] camlp4.4.02+system is not available because your system doesn't comply with preinstalled &
      ocaml-version >= "4.02" & ocaml-version < "4.03". Skipping.
[WARNING] ppx_tools.4.02.3 is not available because your system doesn't comply with ocaml-version >=
      "4.02.0" & ocaml-version < "4.03.0". Skipping.
The following dependencies couldn't be met:
  - deriving -> camlp4
Your request can't be satisfied:
  - camlp4 is not available because your system doesn't comply with ocaml-version >= "4.04".

No solution found, exiting
The former package state can be restored with opam switch import "/Users/softtimur/.opam/backup/state-20160418124642.export" --switch system

然后，我意识到ocamlfind不再工作：

:testweb $ ocamlfind ocamlc -package js_of_ocaml.ppx -linkpkg cubes.ml -o T
-bash: /Users/softtimur/.opam/system/bin/ocamlfind: No such file or directory

PS：node --version给出v6.1.0; npm --version给出3.8.6; ocaml -version给出The OCaml toplevel, version 4.03.0。
js_of_ocaml --version是2.7，但是在opam swtich reinstall system之后，它是-bash: /Users/softtimur/.opam/system/bin/js_of_ocaml: No such file or directory。

有谁知道该怎么做才能使所有这些软件包兼容？



先前：这是在安装npm和node之后以及在执行opam switch reinstall system之前的编译错误：

:testweb $ ocamlfind ocamlc -package js_of_ocaml.ppx -linkpkg cubes.ml -o T
Failure("Ast_mapper: OCaml version mismatch or malformed input")
File "cubes.ml", line 1:
Error: Error while running external preprocessor
Command line: /Users/softtimur/.opam/system/lib/js_of_ocaml/./ppx_js '/var/folders/fn/0rmvqqbs4k76lg5g6b7kll100000gn/T/camlppxffe989' '/var/folders/fn/0rmvqqbs4k76lg5g6b7kll100000gn/T/camlppx02e06a'

另一种方式也给出了一个错误：

:testweb $ ocamlfind ocamlc -package js_of_ocaml -syntax camlp4o -package js_of_ocaml.syntax -linkpkg -o cubes.byte cubes.ml
Fatal error: unknown C primitive `caml_is_printable'
File "cubes.ml", line 1:
Error: Error while running external preprocessor
Command line: camlp4 '-I' '/usr/local/lib/ocaml/camlp4' '-I' '/Users/softtimur/.opam/system/lib/js_of_ocaml' '-parser' 'o' '-parser' 'op' '-printer' 'p' 'pa_js.cmo'  'cubes.ml' > /var/folders/fn/0rmvqqbs4k76lg5g6b7kll100000gn/T/ocamlpp8b28e8

原来：
我的最初目标是编写和编译cubes.ml，使得1）它包装了OCaml函数以创建可在Web中调用的JS函数； 2）OCaml功能和字节码可以在Linux下的命令行中进行测试。

cubes.ml如下：

let () =
  let oneArgument (a: int) = a + 100 in
  Js.Unsafe.global##.jsOneArgument := Js.wrap_callback oneArgument;
  print_string "hello\n";
  exit 0

然后，ocamlfind ocamlc -package js_of_ocaml.ppx -linkpkg cubes.ml -o T应该生成T，这样./T应该返回hello。并且js_of_ocaml T -o cubes.js应该生成cubes.js，以便jsOneArgument的cubes.js函数可以被其他JS或HTML文件很好地调用。

在弄乱软件包之前，./T返回了Unimplemented Javascript primitive caml_pure_js_expr!，这就是为什么我安装了npm，node等的原因。

最佳答案

我切换回OCaml 4.02.3：

opam switch 4.02.3

然后，

eval `opam config env`

然后，

opam install ppx_tools js_of_ocaml

结果，ocamlfind ocamlc -package js_of_ocaml.ppx -linkpkg cubes.ml -o T生成T，而js_of_ocaml T -o cubes.js生成cubes.js。 node cubes.js确实返回hello。

但是，./T仍然返回Unimplemented Javascript primitive caml_pure_js_expr!，为此我将打开另一篇文章...