How do I determine what modules an OCaml library provides?

Question

I'm just starting a project to analyze C programs using goblint-cil.

I know I needed to use a library to import it. The README for goblint-cil says the following:

# #use "topfind";;
# #require "goblint-cil";;
# GoblintCil.cilVersion;;
- : string = "2.0.3"

I then made a dune file requiring it:

(executable
  (libraries goblint-cil)
  (name main))

I have two basic questions about libraries in Ocaml:

1. How do I find out what modules a library or package provides? In the case of GoblintCil it was right there in the README, but I would like to know if this library provides any other modules.
2. What is the relation between libraries, packages, and modules? It seems to me the following are true:

• Every .ml file forms a module by capitalizing it
• Packages are just a collection of libraries and (potentially empty) set of executables
• Libraries are a sub-collection of modules in a package

Are these correct?

Answer 1

You can:

• read the documentation of the package:

  • online at ocaml.org, for instance, https://ocaml.org/p/goblint-cil/latest/doc/index.html.
  • locally, by generating documentation for your installed packages with odig.

• In a toplevel, once you have loaded a library with #require "library_name", you can #show its toplevel module:

#require "base";;
#show Base;;