Utop : not a bytecode executable file

utop
#1

I have installed opam and ocaml through Homebrew. When I run which Ocaml I get /Users/me/.opam/system/bin/ocaml

which opam however gives /usr/local/bin/opam. Is this normal? If so running utop gives me the error /Users/me/.opam/system/bin/utop' is not a bytecode executable file…Can anyone lend some help as to how to go about troubleshooting this?

Running which utop also gives /Users/me/.opam/system/bin/utop

Currently Running MacOS High Sierra. This is happening after an upgrade

#2

You don’t specify how you installed opam and the like. Homebrew perhaps? Regardless, that’s important information. You’re also using a system switch, rather than an opam created switch, which isn’t really recommended.

#3

See if this works for you:

$ opam switch 4.07.1
$ eval $(opam config env)
$ opam install utop
$ utop
#4

Thank you for the reply. Unfortunately running opam switch 4.07.1 results in an error: [ERROR] No switch 4.07.1 is currently installed. Did you mean ‘opam switch
create 4.07.1’?
Installed switches are:
- system

#5

That’s fine, just follow the error messages.
opam switch create 4.07.1

#6

Running opam switch create 4.07.1:
[ERROR] No compiler matching ‘4.07.1’ found, use ‘opam switch list-available’
to see what is available, or use ‘–packages’ to select packages
explicitly.

running opam switch list-available gives: Listing available compilers from repositories: default

No matches found

#7

Yes it was all Homebrew but I did try a MacPorts install that is now gone.

#8

Hmm… perhaps try:

opam update
opam switch create ocaml-base-compiler.4.07.1
#9 
[ERROR] No compiler matching 'ocaml-base-compiler.4.07.1' found, use 'opam
        switch list-available' to see what is available, or use '--packages' to
        select packages explicitly.
#10

That certainly is strange. It’s not finding any compilers? Try removing brew uninstall opam and try getting it directly from the opam releases page, here: https://github.com/ocaml/opam/releases/download/2.0.3/opam-2.0.3-x86_64-macos

Then extract move the file to /usr/local/bin/opam and chmod +x /usr/local/bin/opam

#11

Could it be you forgot to do an opam init ?

#12

I believe I have done one but could not hurt to try. Using Finder to go to /usr/local/bin/opam gives an error. It seems the directory does not exist.

I have also already ran brew uninstall opam

#13 
sudo mv <path to downloaded file> /usr/local/bin/opam
chmod +x /usr/local/bin/opam
#14

Is this mv command supposed to create a new directory? I see opam in /usr/local/bin/ as an executable. I can once again run the opam command but utop gives the error:

Fatal error: the file '/Users/me/.opam/system/bin/utop' is not a bytecode executable file

Maybe I still need to run init now?

#15

No, opam is an executable. I would suggest you start from scratch.

rm -rf ~/.opam
opam init --compiler ocaml-base-compiler.4.07.1
eval $(opam env)
opam install utop
utop
#16

38%20PM

Thank you so much!