Hi,

> I ask you all: can anyone make me a practical example, something
> involving strings, files, the network, an image or sound processing
> algorithm, something vaguely real? Not abstract mathematical
> structures, beautiful algebraic properties and general statements,
> please: the net is full of such tutorials, especially Haskell fan
> sites ;-)

Xavier Leroy's lesson on monads [1] will certainly be too abstract for
you, but the accompanying Caml code [2] might help you to grasp the
concept. You will find there a lot of example of useful monads. You should
have read some tutorial before, though, not to get lost.

Another very concrete example is Lwt [3], a cooperative thread library
written in monadic style. Don't hesitate to follow the link, it's a
documentation targeted at programmers, without categorical issues and so
on. You will need to read a more general tutorial on monads then, to get
the general idea, but it could be a good starting point to "bind" and
"return" operators.

[1] http://gallium.inria.fr/~xleroy/mpri/progfunc/monads.2up.pdf
[2] http://gallium.inria.fr/~xleroy/mpri/progfunc/monads.ml
[3] http://ocsigen.org/lwt

Regards,
-- 
Gabriel Kerneis