OCaml: Can't find version - ocaml

When I enter ocaml --version it returns
/usr/bin/ocaml: unknown option '--version'.
I installed it using OPAM and ran the instructions
opam init
eval $(opam env)
eval opam env
opam switch create 4.07.0
and everything seemed to go fine. Entering which ocaml returns a correct-looking path. And when entering a terminal session it seems to work fine. I don't see this error mentioned anywhere when I search for it.

OCaml tools are weird and usually do not follow the POSIX guidelines of using double dashes for command line options. At this point probably for historic reasons and because the standard Arg module parses command line arguments this way. In any case, this will do the trick:
ocaml -version

Related

coq 8.11.0 incompatible with ocaml 4.10?

I am installing coq with opam as per these instructions and have gotten the error message
`No solution for coq: The following dependencies couldn't be met:
- coq → ocaml < 4.10
base of this switch (use '--unlock-base' to force)
I proceeded to switch to ocaml 4.05.0 with the following command
opam switch create with-coq 4.05.0
and could install Coq successfully, but I'd much rather use the updated version of ocaml. Is this an actual incompatibility between Coq and oCaml, or am I doing something wrong?
For added context, I am now using opam 2.0.6, ocaml version 4.05.0, and Coq version 8.11.0. My operating system is macOS. Prior, the only difference was that I tried to use ocaml 4.10.0.
Thank you!
You need the tip of the v8.11 branch or wait for 8.11.1 which should be out shortly.
You don't need to go back to 4.05.0 tho, 4.09 will work fine, tho 4.07.1+flambda is the one I recommend, see https://coq.discourse.group/t/install-notes-on-coq-and-ocaml-versions-configuration/713

ocaml command line cannot find “topfind”

I've installed opam, run opam init, run opam switch 4.06.0 which created a 4.06.0 directory inside ~/.opam, run "eval opam confing env" which exports $OCAML_TOPLEVEL_PATH as ~/.opam/4.06.0/lib/toplevel amongst other things, when launching ocaml I get the dreaded:
$ ocaml
OCaml version 4.06.0
Cannot find file topfind.
Unknown directive `camlp4o'.
#
I've looked at this and this neither of which address my issue and I'm at my wits' end (first time setting up OCaml). This is my ~/.ocamlinit:
(* Added by OPAM. *)
let () =
try Topdirs.dir_directory (Sys.getenv "OCAML_TOPLEVEL_PATH")
with Not_found -> ()
;;
#use "topfind"
#camlp4o
#thread
#require "core.top"
#require "core.syntax"
EDIT: Looks like I hadn't installed core, installing core resolved that but now amongst the slew of import diagnostics I get:
Exception:
Invalid_argument
"The ocamltoplevel.cma library from compiler-libs cannot be loaded inside the OCaml toplevel".
And then a bit further down:
Raised at file "pervasives.ml", line 33, characters 25-45
Called from file "toplevel/toploop.ml", line 468, characters 4-128
Called from file "toplevel/topdirs.ml", line 144, characters 10-51
Camlp4 Parsing version 4.06.0
You should run
eval `opam config env`
Note the backticks. They are usually located to the left of the key 1 on most modern keyboards. The command should not output anything, if you see any output it means that you're running it incorrectly. You have to run this command to activate the opam installation every time you start a new shell (unless you've put this command in your shell initialization scripts, like .bashrc)
If the problem persists, then make sure, that you have installed the ocamlfind package,
opam install ocamlfind
What seemed to work for me:
make sure core is installed (opam install core)
make sure camlp4 is installed (opam install camlp4)
Insert Topfind.don't_load ["compiler-libs.toplevel"];; in-between #use "topfind";; and #require "core.top";;, as per this. It is an issue that doesn't appear to be fixed in the latest version of core (0.9.2).

How to install a specific version of ocaml compiler with opam

How can I install a specific version of ocaml compiler (and compatible packages) using opam (or another package manger)?
I took a quick look through the opam documentation, but I don't find a relevant information.
I need ocaml compiler (preferably the native code compiler) to build unison, a software for file synchronization. I need to build unison on two machines using the same version of ocaml, or otherwise unison emits an error and aborts its duty (yiiii!).
I tried building ocaml version 4.04.0 from a tar ball and then using it for building unison, but on one of the machine the build of unison failed with the error message,
make[1]: Entering directory '/home/norio/Downloads/unison/unison-2.48.4_expand/src'
ocamlc -o mkProjectInfo unix.cma str.cma mkProjectInfo.ml
File "mkProjectInfo.ml", line 1:
Error: Error while linking /home/norio/Downloads/unison/ocaml_for_unison/lib/ocaml/unix.cma(Unix):
The external function `unix_has_symlink' is not available
if [ -f `which etags` ]; then \
etags *.mli */*.mli *.ml */*.ml */*.m *.c */*.c *.txt \
; fi
make[1]: Leaving directory '/home/norio/Downloads/unison/unison-2.48.4_expand/src'
I don't want to set off for the quest of unix_has_symlink function and devote myself for the exploration of the swamp of library dependencies where many developers had fallen before the civilization came and package managers were invented.
Is there anything like,
opam install ocamlc-4.04 and opam install all-packages?
Addendum
The error message about unix_has_symlink was observed on a machine running Linux Mint 18 Cinnamon 64 bit. Is this function a part of some unix/linux library, rather than ocaml package?
To create a switch with a particular version of the compiler do
opam switch create <compiler-version>
(Note: for the old opam 1.x it was opam switch <compiler-version>)
E.g.,
opam switch create 4.07.0
Or, if you want to create a fresh new switch that uses the same compiler as some other switch, then the syntax is
opam switch create <name> <compiler-version>
E.g.,
opam switch create myproj 4.07.0
Note, that if <name> is a folder, then a local switch will be created, e.g., opam switch ./myproj 4.07.0 will create a switch directly in the myproj folder.
To start with a specific version, i.e., when you first install opam, just do
opam init --compiler=<version>
E.g.,
opam init --compiler=4.07.0
To list available versions do
opam switch
To see even more, do
opam switch list-available
To install a variant of a compiler, e.g., a compiler with flambda or spacetime, use the following general syntax,
opam switch create <switch-name> ocaml-variants.<version>+options <options>...
E.g.,
opam switch create myswitch ocaml-variants.4.13.0+options ocaml-option-flambda
use opam search ocaml-options for the full list of available options. It is possible to specify several options, e.g.,
opam switch create myswitch ocaml-variants.4.13.0+options ocaml-option-flambda ocaml-option-spacetime ocaml-option-static

Telling ocamlbuild to use Core

In my project I have a file that uses Core.Std stuff, so I have run
opam install core
and added
open Core.Std
in my file.
When I run
ocamlbuild myprogram.native
it says:
Error: Unbound module Core
pointing to line with the open statement above.
So, I try this:
ocamlbuild -use-ocamlfind -pkgs core.std myprogram.native
and get the following message:
ocamlfind: Package `core.std' not found
So I thought that maybe I needed to run opam install core.std as well, but apparently there is no such thing according to opam. I also tried "open Core.Std;;" in the ocaml repl, but that did not work either. Any ideas?
You can either use corebuild which is usually shipped with this library or, you can try this:
ocamlbuild -use-ocamlfind -pkg core
P.S. use ocamlfind list command to view the list of available packages.
P.P.S. In addition to corebuild they usually ship coretop, a script that allows you to run core-enabled top-level. It uses utop underneath the hood, so make sure that you have installed it with opam install utop (if you're using opam), before your experiments.
Remove .std from your ocamlbuild cmd?

ocaml batteries installation

There seems to be conflicting information about batteries installation. I have tried several suggestions, but none have worked for me.
I first tried
ocamlfind batteries/ocaml
but that gave this error:
ocamlfind: Cannot find command: /username/godi/lib/ocaml/pkg-lib/batteries/ocaml
I then tried copying the ocamlinit file from the batteries directory to .ocamlinit in my home directory. This gave this error:
Cannot find file topfind.
File ".ocamlinit", line 38, characters 0-20:
Error: Unbound module Toploop
I am using ocaml 4.00.1.
Note: I apologize if this question is redundant with this one ocaml batteries compiling : Unbound module Toploop but the answer given was not explicit enough for me to actually try.
Like #rgrinberg said, try to install batteries with opam. For that, first download the quick installer:
$ wget http://www.ocamlpro.com/pub/opam_installer.sh
Then execute this script:
$ sh ./opam_installer.sh /usr/local/bin
It will install the latest "stable" opam (you can of course change the path /usr/local/bin) and the latest version of the OCaml compiler.
After that, you just need to run:
$ opam install batteries
and it should be ok.
You can also check ocaml.org install section (by package manager) or opam website.