Re: [Caml-list] OCaml vs Ada and/or GUI options

[Alain Frisch <alain@frisch.fr>]

We have done some experiments running LexiFi's core libraries (symbolic 
manipulations of terms representing financial contracts) in the browser, 
using js_of_ocaml.  We also played with dynamic GUI generation directly 
in the browser, based on our runtime type extension (which works fine 
with js_of_ocaml).

Overall, we were impressed by the easiness to integrate js_of_ocaml (no 
need to patch the compiler or do big changes to the build system) and 
its faithfulness to the semantics of OCaml.  Really no big bad 
surprises, and it was amazing to see a complex piece of software running 
in the browser.  js_of_ocaml opens many interesting doors for using 
OCaml in web development!


(((Some points which required some special care:

   - Support for C primitives.  Each primitive called by the bytecode 
needs to have a Javascript implementation.  Since LexiFi's version of 
OCaml is most often synchronized with OCaml's trunk than with a stable 
release, we had to implement the new primitives.  This raises the 
general point that js_of_ocaml will need some active maintenance, even 
if the OCaml bytecode itself is very stable across versions.

  - A tiny semantic difference: in OCaml, the expression 
"String.unsafe_get s (String.length s)" returns '\000', which gives an 
efficient way to iterate over a string without checking for the 
end-of-string condition explicitly.  This hack (which is also used in 
the stdlib module, btw) does not work with the way strings are 
represented in js_of_ocaml.  That said, we were quite happy to see that 
other low-level hacks we do with the runtime representation of values 
worked well (setting a block tag to Object_tag to force generic 
comparison and hashing to use the second field; or playing with the 
representation of method tables to memoize method calls).

  - The lack of weak hash tables, which we use quite a lot.  I wonder if 
Firefox's experimental WeakMap could be used to simulate them (and if 
other browsers will get similar features).

  - Reliance on Camlp4 for interacting with Javascript.  Getting rid of 
this dependency was our first internal use of -ppx!
)))


Alain




On 09/18/2013 01:42 PM, Gour wrote:
> On Wed, 11 Sep 2013 13:42:49 +0200
> Gerd Stolpmann <info@gerd-stolpmann.de> wrote:
>
>> We would need an HTML5 binding so the programmer wouldn't see the
>> Javascript part.
>
> In my search for adequate GUI bindings I've found out about OCaml
> bindings (https://github.com/astrada/ocaml-extjs) for ExtJS
> (http://www.sencha.com/products/extjs/) so wonder what is your
> experience with js_of_ocaml in generall and/or ExtJS?
>
>
> Sincerely,
> Gour
>