This is an effort to allow you to build a gen_server from a prolog file with a custom API that can be defined in prolog. It is a very early stage right now everything can and may change.
Pull Requests welcome!
This is designed so that you can create a prolog module .pl and compile it down to a beam file which will run as a gen_server.
In your prolog file you should tell it which functors to export by
using the erl_export/3 predicate, where the first item is the
functor to return, the second is the atom return and the final is
either last or none Last will return the last parameter, none will
just return ok. (the examples are taken from the po_sets.pl file
in the priv directory.
erl_export(path/3, return, last).
path(A,B,Path) :-
travel(A,B,[A],Q),
reverse(Q,Path).
This will create a module that has the Erlang function that takes the PID of the server and the other parameters and returns the return value specified in prolog.
path(Erlog, A,B) ->
Path.erl_export(add_edge/2, return, none).
add_edge(A,B) :-
...add_edge(Erlog, A, B) ->
%code here
ok.If you ask for a return type of none then it will simply return
ok if the predicate succeed and crash if it failed.
Currently to compile a file you the function
erlog_make_server:compile_file/2 pass it the path to the file and an
atom for the erlang module name. A rebar plugin will happen sooner or later.
If you want to have your erlog server running from a supervisor, then
the generated module will include a function
make_supervisor_childspec which will generate a basic child_spec
that will enable you to hook it up to a supervision tree.