Re: [Caml-list] Question about Lwt/Async

[Yotam Barnoy <yotambarnoy@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 3532 bytes --]

Is there an existing compatibility library functorized over the
intersection of Async and Lwt? That would make being compatible with both
much easier.

On Mon, Mar 7, 2016 at 4:08 AM, Simon Cruanes <simon.cruanes.2007@m4x.org>
wrote:

> Hi,
>
> It seems that Lwt is more popular in the community
> outside JaneStreet than Async (if only by looking at its reverse
> dependencies on opam.ocaml.org). There has been posts about this, for
> instance http://rgrinberg.com/blog/2014/12/11/abandoning-async/ .
> However, if you're writing a library, it is good taste (if possible) to
> parametrize you code over an "IO" monad that will be easy to instantiate
> with either Async or Lwt (or the trivial blocking monad where 'a t = 'a
> and (>>=) x f = f x) along with the required IO primitives.
>
> Regarding general utility functions, if they do not perform IO or depend
> on (blocking) IO they can be used directly with Async/Lwt (unless they
> really take a very long time to complete).
>
> Le Mon, 07 Mar 2016, Malcolm Matalka a écrit :
> > Yotam Barnoy <yotambarnoy@gmail.com> writes:
> > > Hi all
> > >
> > > I'm thinking about my next project in OCaml, and I'm wondering how many
> > > users of OCaml currently use Lwt or Async regularly.
> > >
> > > One of the advantages of OCaml over Haskell (which I'm not crazy
> about) is
> > > the fact that you don't have to constantly be stuck inside a monad.
> > > However, once you want to use these user-level threading libraries,
> you're
> > > essentially tied to a monad. It also means that the usage of any other
> > > monad from Lwt/Async code is out -- OCaml doesn't have the monad
> > > transformer infrastructure to layer monads easily as far as I can tell
> (am
> > > I wrong?). I mean, even in Haskell using Monad Transformers is a pain
> (IMO).
> > >
> > > Also, what happens to general utility functions that aren't rewritten
> for
> > > Async/Lwt -- as far as I can tell, being in non-monadic code, they will
> > > always starve other threads, since they cannot yield to another
> Async/Lwt
> > > thread. Is this perception correct? If so, this seems to imply that you
> > > either write your code to cooperate within these frameworks and suffer
> the
> > > monad, or don't, and make it near-impossible for Lwt/Async users to
> make
> > > use of your code.
> > >
> > > I would like to get an idea of the usage level of these libraries, as
> well
> > > as the burden of writing compatible code, any difficulties etc. Also,
> I'd
> > > like to get a sense of the domains that benefit from these libraries.
> Some
> > > domains (such as gaming) traditionally involve a continuous main loop,
> and
> > > would thus only suffer from the additional overhead of queuing in these
> > > libraries.
> > >
> > > -Yotam
> >
> > I mostly use Async.  However, I think most usage of Lwt or Async
> > requires doing as little as possible in these frameworks and using them
> > to orchestrate other functions.  For example, I usually try to separate
> > parsing of a network protocol from the reading and writing of the bytes.
> >
> > --
> > Caml-list mailing list.  Subscription management and archives:
> > https://sympa.inria.fr/sympa/arc/caml-list
> > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> > Bug reports: http://caml.inria.fr/bin/caml-bugs
>
>
> --
> Simon Cruanes
>
> http://weusepgp.info/
> key 49AA62B6, fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA
> 62B6
>

[-- Attachment #2: Type: text/html, Size: 4859 bytes --]