Re: Core screwed up Utop.

But I did use opam!  Or at least I thought I did.    :-(     Oh well, I'm
glad this is not my only computer!!!

On Sat, Sep 24, 2016 at 6:17 PM, Kenneth Miller [email protected]
[ocaml_beginners] <[email protected]> wrote:

>
>
> You did all that stuff manually when you could have been using opam??
>
>
> On Saturday, September 24, 2016 6:20 PM, "Douglas Lewit [email protected]
> [ocaml_beginners]" <[email protected]> wrote:
>
>
>
> Hi everyone,
>
> I went on github ( a real computer jungle for sure! ) and upgraded to
> Ocaml 4.03.  Then I installed Core, which I believe is a library containing
> all of Jane Street's contributions to the Ocaml language.  That screwed up
> my Utop installation, so I tried to reinstall Utop.  No success with that.
> There were many error messages, but the primary failure had to do with a
> dependency called "*lwt*".  I did a Google search and discovered that
> some other Ocaml users have had problems with this dependency as well.  I'm
> not really sure how to fix it.  I can still use Ocaml's default top-level,
> which is okay, but Utop is really fantastic!  Utop is way better than
> Ocaml's default top-level.  Any suggestions?  Much appreciated.
>
> Best,
>
> Douglas Lewit
>
> P.S.  Could someone provide some feedback on the following code?  It works
> well for getting every nth member of a list, but isn't there an easier way
> to do this?  I just thought it was a lot of work to accomplish a more or
> less simple task.  Thanks.
>
> *let everyNth ls n = *
> *     let rec everynth lst m = *
> *                match lst with *
> *                |[ ] -> [ ]*
> *                |head :: tail -> if m mod n = 0 then head :: everynth
> tail (m + 1)*
> *                                       else everynth tail (m + 1) in *
> *                everynth ls 1 ;;*
>
> An interesting side note here.  This recursive function can be implemented
> in Ruby, but of course the syntax is a tiny bit different.  ( For example,
> instead of match lst with [ ] or head :: tail you would do something like
> if lst == [ ] then [ ] else head, *tail = lst ......... etc, etc.  But
> what's really interesting is that with Ruby the inner function must be
> declared as a lambda expression.  If it's a regular function defined using
> the "def" keyword then the inner function cannot "see" the variable n.
> It's interesting to me how Ruby and Ocaml not only have different syntax
> but also somewhat different rules regarding the scope of variables within
> functions and nested functions.  Ruby of course is mostly object-oriented,
> but its creator was a very avid LISP programmer and for that reason decided
> to endow Ruby with certain important functional features.  So even though
> Ruby is mostly object-oriented the language has some powerful functional
> features that remind me a lot of Ocaml, LISP, Haskell, Erlang, etc, etc.
> For example, Ruby does a pretty good job at recursion, currying, etc.
> Okay, that's it for now.  Thanks!
>
>
>
> 
>