World: r3wp

it used to be that I was scared the spec of liquid would change too 
much and I would run into support issues, but so far, its remained 
backwords compatible for the last year... and I have implemented 
VERY complex systems using it, so I am now confident its in a state 
of production approval.

I sue similar tricks as a teacher, maybe you made the right choice

sue=use

hehe.

See you

ciao and thanks for the interest... any question you have, I'll be 
happy to answer.

max... i've been studying liquid and how it can be used (or not ;) 
in vid+ (or vid2 or vid3 or whatever we want to call it)

my conclusion is the same as nenad's... it's overkill :) i think 
i can do all that users need to do with just event handling. that 
is, recognizing that in the ui everything is about events. the system 
does not need a network, just direct "links" between elements (call 
them widgets, styles, etc).

from the user pov, it looks like a network, but internally it is 
not. in particular, events don't need to be propagated (this avoids 
the cycle problem altogheter)

i'm interested in examples where this would not work. (i think i 
can reproduce all examples i have seen from you so far, ie. sliders 
attached to fields and so on)

Does it make it easier for ordinary programmers though?

Just in Mozilla: Was reading rss in sage, opened bookmark-editor, 
moved bookmarks, sage was updated. i think liquid is for such things. 
also the wiring can be shown graphically. Have seen that with Visual 
Age did that long ago. If it is well done its not a bad idea. I still 
fear it will be hard to debug, since all this wiring is invisible. 
Or maybe: it was to easy to create for me. BAck in that days i found 
such connetion-stuff cool and created a lot spagethi. (was not using 
VA, that method worked with pure oops too^^)

Later i moved to oberon. Oberon does not use explicit connections. 
Instead each event is broadcasted to everything. WHich may broadcast 
it to its inner parts. I found that to be easier and more flexible.

Well, if we interface to user via a dialect, then it is ok to me. 
The thing is - web is full of various frameworks. I read about them, 
about their ideas, and it is OK. The trouble is, that for the thing 
to be usable, you have to study, what the framework author though 
about, when he/she was creating a framework. And I fear, that way 
too much abstract framework will distract coders, as they will not 
understand, how to extend it, etc.

graham, i believe easier than using liquid ;) on the dialect level, 
you just use "attach" like max does in liquidgl.

I think that VID is nice. Dialected aproach is the way to go, that 
is for sure. I would be OK, if VID would fix some things as - tabbing, 
cursor change, accelerator keys, visual focus representation to widgets, 
disabling/enabling (for business wide widgets), resizing, methods 
for drag & drop etc. Look e.g. at VID's feel - it was abstracted, 
that you have central storage of "feels", but was that abstraction 
used to any good by anyone? I like self-contained styles/widgets 
of rebgui better.

Let's create new VID, which will be both easy to use from user perspective, 
yet easily extensible for developers. That means, that engine has 
to support those basic functionalities from the very beginning, otherwise 
we will be in the trap once again ...

petr, we may not be able to deliver all of that for july (or maybe 
yes, depending on community help), but it's certainly planned and 
will happen

volker: broadcasting to everything... do you think that scales well?

Gabriele - that is still nice. I did NOT expect View to be released 
at all, so ....

I thought Core comes first (but more complete), then View ...

the compositing engine is almost ready... so why not release it.

we may not be able to emulate r2 faces in july... so no compatibility... 
but other than that it should be functional

Gabriele - but, what I would not like to see is - to start with system, 
which is not flexible enough - e.g. old VID - you CAN'T add some 
things later, unless you count on them from the very beginning! Then 
docs appear, ppl start to produce scripts, and then we complain that 
we can't change it, because there is lots of dependency ;-) Please 
bear in mind, that NOW is the time for the change ...

Gabriele, did i notice i used Oberon? :)

Fastest thing i have seen on a P100. Maybe muchmore on Amiga could 
compete :)

that may mean that they were smart, it doesn't mean that broadcasting 
scales well. ;)

eg. imagine if every face got every event.

also... we have network events, system events, you could have usb 
events and many more... do you broadcast everything to everything? 
when an event generates another event, is it broadcast to everything? 
it does not seem a great model to me... :)

Gabriele - is there new event system in View? IIRC we were thinking 
along the lines of plugging some external library into rebol - libevent, 
liboop, etc.

It works for the gui. I dont step into theory about slow, if i have 
a real life example which is fast :) about everything to everything, 
that would be in a bad case: each event to 100 receivers, 100 events/sec, 
10k dispatches/sec. cpu can do 1 billion instructions. 10k instructions/event. 
most of them: i am interested? no. ~100.

100k instruction/event.

petr, yes and no. yes in the sense that events come from devices, 
no in the sense you mean (libevent). i don't see why we would need 
libevent or anything like that.

volker... oberon may be doing tricks, such as not really broadcasting 
to everything... so the fact that it is fast does not make the approach 
a good approach.

No multithreading on Oberon (back in the day - Active Oberon has 
it now). They managed multitasking through shared memory structures 
and other interesting tricks.

Because of this it was able to manage a full GUI and still be as 
fast as DOS.

Single process, no virtual memory - through other tricks, they managed 
to avoid needing it. Because of this the event broadcast, like everything 
else it did, ran by itself on the bare metal. Hence the speed.

Gabriele, liquid (dataflow) adds a level of stability to any project. 
 the fact that its lazy pays off very well so far.

the system in its current form is not meant to be easy to code  (for 
maintenance reasons).  I know many ways to change this, but before 
going to far, I had to have as stable an architecture as possible.

I have gone through 3 rewrites before hitting this sweetspot.  other 
versions might have been simpler in a way, but left the system, non 
generic and unscalable in one of many different ways.

liquid's strength lies in the fact that it is generic.  we all write 
dataflow within our applications, without realising it.  but we then 
recode each little system in its own isolated architecture.  this 
means we just loose a lot of time.

I was able to write elixir in about 40-50 hours of time and the only 
bugs it has are within the parts of code which has no dataflow.  
everytime I trust liquid and switch part of the code to it, I end 
up forgetting about that part, because it gets to be so stable.

I am as anxious as all of you and understand ALL of your qualms about 
using dataflow and liquid. 
 *complexity?
 *speed?
 *scalability?
 *difference in programming model
 * ....

The truth is, I do not have the reflex of using liquid for most of 
my coding, still, but actuall exposure and use, is forcing me to 
value its effect on my code.  this is empiric use, not advocacy. 
 If you could see just how easy it was for me to build fully bug-free 
AGG gadgets in so little time, you'd understand.


its not about just sharing data between gadgets, its about allowing 
your code to know what's going on.

and in fact, if we do add a measure of reflexivity to VID, we will 
just be redoing most of liquid, or run in the same issues, I had 
in my other prototypes, which led to this design.   ;-)

but we will not gain the advantage of having generic dataflow!

max: liquidgl is push based, isn't it? so "lazy" does not count.

nope, its all using the same core plug.  so its really pull based.

the only difference is that some (switcheable in real time, even 
set to a function) which will always want to refresh, when they are 
aware of data changes.

when you move a slider that is attached to something, is that something 
that has to pull? does it pull x times a second?

its also nice to know that your GUI is actually capable of reflecting 
data.  not just gui.  change the data:

fill data value


and don't even have to wonder IF and HOW any gadget should change.

that is push, isn't it?