How to include other source files using the #use directive in OCaml?

Question

I am new to OCaml and I would like to put part of the code in another file, say foo.ml , like in C ++ or Python. But this piece of code alone does not form a module.

I included #use "foo.ml" at the beginning of my main source file. But when I create my project using ocamlbuild , it reports I/O error: "foo.ml: No such file or directory" . But it is clear that foo.ml is in the current working directory.

I wonder if anyone knows how to achieve this goal in OCaml, and let my project be built, or if it is not an agreement in OCaml? Any suggestion is welcome.

Answer 1

#use "foo.ml" is a directive for the interactive top level; it does not work with the compiler.

If you want to split your code into different files (which is a good idea and highly recommended in OCaml), you should use a module system. Why are you saying that your code does not form a module? If your code consists of only one-time functions, they should be in the same file as the functions that use them. If your code is reused, it forms a module.

Answer 2

As Tomas said, this is probably the wrong solution to your problem.

If you need it, you should use camlp4 or external tools like cppo .

example for pa_macro (comes with ocaml):

test2.ml:

 let arg = "Hello World" 

test.ml:

 INCLUDE "test2.ml" let () = print_endline arg 

compilation:

  ocamlfind ocamlc -syntax camlp4o -package camlp4 -ppopt pa_macro.cmo test.ml -o test