[mysidia@flame.org: Re: [CIRCLE] Embedding Perl into CircleMUD]

From: Mysidia (jmhess@i-55.com)
Date: 09/08/02

> Already had that working before I sent the email. :)  What I am particularly
> interested is the actual CircleMUD implementation.  In this case, I am going
> to use this for our spell system, so I need some sort of design idea on how
> to treat the data needed for the Perl-scriped spell code.  For instance, how
> would I pass data between the Perl script and Circle?  Those kind of
> implementations are what I cannot understand yet.  I mean, I understand how

How you would pass data around depends on what your embedding library

Ideally, you pass data between script and code in a manner similar to
how that data's stored.

Data exchange is actually the hard part -- chances are you need to
create some OO perl structures to pass data back and fourth.

Another possibility is to have C hooks for building the data, in
this example all af_* and make_affect() would be C functions that
map appropriately and handle their arguments:

sub bless_char
     $x = make_affect();  /* `$x' may very well be a string representation,
                              holding binary codes organized in a particular
                              manner that would be meaningful to the data
                              exchange process but look like hieroglyphics
                              to a human: it doesn't matter, so long as it
                              can be interpreted by what needs to read it */

     af_set_duration($x, 3);
     af_set_location($x, APPLY_HITROLL);  /* You probably need to
                                    write a constants.pm file to
                                    include to use things like APPLY_*/
     af_set_modifier($x, 3);
     af_set_type($x, SPELL_BLESS);
     af_affect_to_char($x, shift $_);

Chances are though, that your perl embedding library provides a way
to emulate more complex data structures like aggregate structs,
where if you map properly you could have

sub bless_char
     $ch = shift;

     $x->duration = 3;
     $x->location = APPLY_HITROLL;
     $x->modifier = 3;
     $x->type = SPELL_BLESS;

     af_affect_to_char($ch, $x, 0, 0);

The perl code becomes structurally simpler, except the data exchange
becomes more complex (perhaps especially for things like strings)
-- an advantage of making all changes with individual functions
is that only the data you need to change has to be exchanged
(other than the return of the bits that represent a structure)


   | FAQ: http://qsilver.queensu.ca/~fletchra/Circle/list-faq.html |
   | Archives: http://post.queensu.ca/listserv/wwwarch/circle.html |
   | Newbie List:  http://groups.yahoo.com/group/circle-newbies/   |

This archive was generated by hypermail 2b30 : 06/25/03 PDT