[DGD] LWO

Thu Aug 13 02:08:59 CEST 2015

Bart:  What are some practical applications for operator overloading?
On Aug 9, 2015 8:00 AM, <bart at wotf.org> wrote:

> I noticed 2 bugs in the code I posted (not handling ranges properly when
> beginning or end not specified, and not handling the difference between 0
> and
> nil in the | operator), both fixed.
>
> As to open-sourced libraries for DGD, Iirc Shentino is maintaining an
> open-sourced lib (or 2 actually?), and there is klib of course (also
> maintained by Shentino nowadays if I'm not mistaken), and Felix maintains a
> lib called cloudlib, which is very interesting codewise, but seems rather
> incomplete for as far as building a mud goes.
>
> Every so often, when people ask about things, I'll post some examples (if
> possible as public domain, so they can be used by everyone without
> licensing
> concerns).
>
> Beyond the things mentioned above, I don't think there is anything
> open-sourced that runs on modern versions of DGD and can take advantage of
> at
> least some of the features that make DGD special.
>
> In general, you'll have to make some choices. Current Gurbalib seems to
> aim at
> simplifying the codebase to provide something that is relatively easy to
> understand and use, but at the expense of some of the complexity,
> infrastructure and restrictions needed to run DGD as a persistent server
> and
> for example support for a verb based user interface.
>
> This doesn't have to be an issue if you want to use it for a classic lpmud
> style lib for example, but may be limiting if you aim for a 'new'
> persistent
> mud with a persistent world and managed in-game economy.
>
> Picking between those 2 styles or consciously deciding on a mix (and on
> solutions to the various conflicts this causes) is very important, doing so
> much later on will involve lots and lots and lots of extra work, and
> depending
> on the size of your codebase, may not even be a feasable option (trust me
> on
> this one, I went this way with Way of the Force, and it took about half a
> decade to find and address the more prominent issues).
>
> At any rate, Gurbalib is your best starting point when wanting to run
> something lpmud alike, and has an active maintainer and a small but active
> community, but its not a very good starting point if you aim at something
> that
> isn't very lpmud like.
>
> Bart.
>
> On Sat, 08 Aug 2015 19:38:53 -0400, Littlefield, Tyler wrote
> > -----BEGIN PGP SIGNED MESSAGE-----
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> >
> > This is cool, thanks. I got what I was trying for working today.
> > Are there many different systems open-sourced in LPC? I'd like to see
> > how things are done, most especially with DGD.
> >
> > Thanks,
> > On 8/8/2015 10:19 AM, bart at wotf.org wrote:
> > > An example LWO can be found at:
> > >
> > > http://wotf.org/downloads/lpc/kvset.c
> > >
> > > It should work on gurbalib directly (and with little or no
> > > modification on about every other lib).
> > >
> > > It implements a variation on the mapping type that adds support for
> > > &, | and - operators.
> > >
> > > Bart
> > >
> > > On Sat, 8 Aug 2015 12:05:05 +0200, bart wrote
> > >> Creating an LWO is easy:
> > >>
> > >> object src; object lwo;
> > >>
> > >> src = find_object( "/path/to/some/object" ); lwo = new_object(
> > >> src );
> > >>
> > >> lwo will be the lightweight object, src is a blueprint object
> > >> used as a template for the lwo.
> > >>
> > >> Note that an object does not have to do anything special to be
> > >> usable as lwo, but there are some differences between a clone of
> > >> a blueprint object and an lwo:
> > >>
> > >> Very important: lightweight objects do not get destructed
> > >> explicitly, they simply are forgotten when nothing references
> > >> them anymore. This means (very important if you are trying to do
> > >> any kind of object management or data storage on destruct) there
> > >> will be NO calls to the lwo informing it that it is going to be
> > >> destructed. This is a simple fact and not something that you can
> > >> code your way around, it is a consequence of the nature of LWOs.
> > >>
> > >> LWOs can *NOT* have call_outs. Again, this is a consequence of
> > >> the nature of LWOs. Do not use LWOs for code that must use
> > >> call_outs or move the call_outs to some other bit of code not in
> > >> an LWO.
> > >>
> > >> LWOs are kept in the storage space of the object that created
> > >> them (did the call to new_object()). ALL the things that apply to
> > >> arrays and mappings that are passed by reference from one object
> > >> to another also apply to LWOs. This means they will only be
> > >> shared until the end of the execution round, after which a copy
> > >> will be made and both objects involved will end up having their
> > >> own copy of the LWO.  For example, you might want to keep track
> > >> of some centralized counter for something. You decide to stick
> > >> this in some object, and let everything that needs this counter
> > >> call the object. So far so good, and this works with blueprints
> > >> (as you can simply use find_obect() and are guaranteed to end up
> > >> at that blueprint) or clones (you have to pass the object
> > >> reference to code that needs it). Doing this with an LWO however
> > >> may or may not work depending on exactly how you implement this:
> > >> - pass lwo reference to other object, which uses it to reference
> > >> the counter and then forgets it, all in the same execution round:
> > >> this works - pass lwo reference to another object which stores it
> > >> and then later on (as the result of a call_out or other user
> > >> action) tries to use it: this will not work as expected as the
> > >> LWO is no longer the one that was stored originally, it is a copy
> > >> of it.
> > >>
> > >> Also important, LWOs support features that regular clones do not,
> > >> especially operator overloading (see the git commit log for dgd,
> > >> look for the keyword operator).
> > >>
> > >> Anyway, there are things for which LWOs are an absolutely
> > >> brilliant solution, things like building advanced data types (for
> > >> example mappings that can contain a lot more then 16384 key/value
> > >> pairs), but also things for which they are a very cumbersome
> > >> solution that is best be avoided.
> > >>
> > >> So.. creating them is easy, making good use of them however
> > >> requires some more careful thought really, they are not 'just an
> > >> alternative for clones', rather, they are something totally
> > >> different then clones, and generally things that need clones
> > >> cannot easily be done with LWOs and the other way around.
> > >>
> > >> Bart.
> > >>
> > >> On Sat, 08 Aug 2015 03:33:39 -0400, Littlefield, Tyler wrote
> > > Hello all: I've been looking for examples. Is there a syntax for
> > > creating an LWO? Any help appreciated. Thanks, - -- Take care, Ty
> > > twitter: @sorressean web:http://tysdomain.com pubkey:
> > > http://tysdomain.com/files/pubkey.asc
> >
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> > >>
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> > >
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> >
> > - --
> > Take care,
> > Ty
> > twitter: @sorressean
> > web:http://tysdomain.com
> > pubkey: http://tysdomain.com/files/pubkey.asc
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