CODEWITHSUNDEEP
ocamlopamutop
pseudoramble
pseudoramble

Reputation: 2561

Error: Unbound module Core when attempting to open Core module with utop from command line

I am trying to follow along with Real World OCaml by setting up opam, utop, and the Core modules as well. I've followed these directions with some success. In particular, when I run utop without specifying the file to load, I can load Core with no issues:

[dswain@Dupree scratch]$ utop
Welcome to utop version 1.12 (using OCaml version 4.01.0)!                                                                                    

Findlib has been successfully loaded. Additional directives:
...

utop # open Core;;
utop #

So far so good. Now if I attempt to load a script from the command line with the same code:

[dswain@Dupree scratch]$ cat test.ml 
open Core.Std;;
[dswain@Dupree scratch]$ utop test.ml 
File "test.ml", line 1, characters 0-13:
Error: Unbound module Core
[dswain@Dupree scratch]$

I assume this is a configuration mistake I've made somewhere, but I'm not quite sure where.

Setup details

I've attempted to reinstall ocaml, opam, utop, and core to no avail. I've got the following config changes that I'm aware that opam init made during setup:

~/.ocamlinit:

#use "topfind";;
#thread;;
#camlp4o;;
#require "core.top";;
#require "core.syntax";;

~/.bash_profile

# OPAM configuration
. /home/dswain/.opam/opam-init/init.sh > /dev/null 2> /dev/null || true

eval `opam config env`

I'm running Arch Linux, and followed the steps to install opam via the AUR with no issues I'm aware of. I was also able to build & install all of the packages from the installation instructions without any errors I know of.

Upvotes: 0

Views: 4545

Answers (1)

ivg
ivg

Reputation: 35210

This is because utop executes a script-file before it runs .ocamlinit file. I'm not sure whether it is a bug or a feature, but that is how the code is written. Indeed, most users runs utop from emacs and send pieces of code to utop with C-c C-s.

If you're not comfortable with emacs, I can suggest to use the following workflow:

  1. start utop
  2. do some coding in your favorite editor
  3. load code in utop with #use "your_file.ml";;
  4. play with it, if not satisfied goto 2.

Upvotes: 2

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