Comparing OCaml and Standard ML

Post by bjz_ » Thu, Oct 23, 2014, 3:06 PM UTC

larsberg wrote: post #29

sgeisenh wrote: post #2

Purity is almost used in a pejorative sense throughout the page. If it wasn't for poor library support, I would prefer using SML to OCaml. SML is syntactically simpler and both SML/NJ and MLton have a lot to offer that I haven't yet found with OCaml. I think one of the biggest mistakes in the life cycle of SML was premature specification. As a result of the language definition, SML has stagnated for almost 20 years.…

I agree completely with your library statements. > I think one of the biggest mistakes in the life cycle of SML was premature specification. I disagree. There were some earlier Successor ML efforts ~10 years ago (see: http://successor-ml.org/index.php?title=Main_Page ), but as I understand it, there was agreement on many of the small issues but larger challenges reaching consensus on bigger changes. You can see some…

Post by pjmlp » Thu, Oct 23, 2014, 3:29 PM UTC

fithisux wrote: post #25

p4bl0 wrote: post #3

Small update: recent versions of OCaml have immutable strings too. It also miss mention of package manager (OCaml has Opam, which is awesome, I don't know about SML). And ocamlbuild is missing from the build tools section.

My only reservation with Ocaml is that there does not exist a package management system for windows or even cygwin. I cannot understand why OPAM takes so much to work on Cygwin. I like SML but it still does not have a good set of libraries. I understand that these projects are sort of resources but supporting cygwin well should be easier than mingw or VS.

Post by p4bl0 » Thu, Oct 23, 2014, 3:33 PM UTC

tomp wrote: post #20

p4bl0 wrote: post #18

Earlier quoted context omitted.

Any decent programming editor will be able to indent that properly and you will see the problem. Also, I agree that it is a bit ugly but it's not that complicated to understand how the match syntax works. Adding a "begin" and an "end" in this code is simple enough :).

It's not just the match syntax; it's also the `;` expression separator. > Any decent programming editor will be able to indent that properly and you will see the problem. This seems like a weak excuse. In particular, I could turn it around and say, "any decent programming language should be writable without an editor". Also, the issue isn't just reading, it's writing too - it's much harder to foresee/plan all the `be…

Post by tomp » Thu, Oct 23, 2014, 3:39 PM UTC

[deleted] wrote: post #35

tomp wrote: post #22

Earlier quoted context omitted.

1) Ignore indentation (I intentionally wrote it to deceive, but similar examples could easily appear in real code). 2) `match` cases always bind to the innermost `match` statement. 3) Statement separators (`;`) are tricky. The correct indentation of the above code is: if a > 0 then print_endline "a > 0" ; match a with | 0 -> print_endline "impossible" | 2 -> match b with | 0 -> print_endline "2, 0" | _ -> print_endli…

[deleted]

  # if false then print_endline "false" ; match () with () -> print_endline "match";;
  match
  - : unit = ()

Post by p4bl0 » Thu, Oct 23, 2014, 3:49 PM UTC

arjunnarayan wrote: post #26

tel wrote: post #21

Earlier quoted context omitted.

As someone without too much OCaml experience, how do you disambiguate this?

There are two things to remember. The first is the match binding thing that tomp mentions in his reply. The second one is that in OCaml, semicolon is a separator, and not a terminator. In contrast, in C/C++, semicolon is a terminator. If you have an expression, you end it with a ";" just because. This is not the case for OCaml. In OCaml, semicolon is used to separate two sequential expressions where only one expressi…

    if  then ; else 

    # if true then (); 1 else 2;;
    Error: Parse error: [str_item] or ";;" expected (in [top_phrase])
    # if true then begin (); 1 end else 2;;
    - : int = 1
    # if true then ((); 1) else 2;;
    - : int = 1

    # match true with | true -> (); 1 | false -> 2;;
    - : int = 1