Make compatible ocaml, camlp4, ppx, node, js_of_ocaml, ocamlbuild

After installing npm and node, compiling OCaml files with js_of_ocaml gave errors, thus I did 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

Then, i realized ocamlfind did not work anymore:

: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 gives v6.1.0; npm --version gives 3.8.6; ocaml -version gives The OCaml toplevel, version 4.03.0. js_of_ocaml --version was 2.7, but after the opam swtich reinstall system, it gives -bash: /Users/softtimur/.opam/system/bin/js_of_ocaml: No such file or directory.

Does anyone know what to do to make all these packages compatible?

---

Earlier: Here were the compilation errors after installing npm and node, and before doing opam switch reinstall system:

: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'

Another way also gave an error:

: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

---

Initially: My initial goal is to write and compile cubes.ml such that 1) it wraps an OCaml function to make a JS function that can be called in web; 2) the OCaml function and the bytecode can be tested in a command line under Linux.

cubes.ml is as follows:

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

Then, ocamlfind ocamlc -package js_of_ocaml.ppx -linkpkg cubes.ml -o T should generate T such that ./T should return hello. And js_of_ocaml T -o cubes.js should generate cubes.js such that the function jsOneArgument of cubes.js can well be called by other JS or HTML files.

Before I messed up the packages, ./T returned Unimplemented Javascript primitive caml_pure_js_expr!, that is why i installed npm, node, etc...

I switched back to OCaml 4.02.3:

opam switch 4.02.3

Then,

eval `opam config env`

Then,

opam install ppx_tools js_of_ocaml

As a result, ocamlfind ocamlc -package js_of_ocaml.ppx -linkpkg cubes.ml -o T generates T, and js_of_ocaml T -o cubes.js generates cubes.js. node cubes.js does return hello.

However, ./T still returns Unimplemented Javascript primitive caml_pure_js_expr!, I am going to open another post for that...