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World: r3wp

[Tech News] Interesting technology

Volker
15-May-2006
[742x3]
I always code with parens in mind. I understand that rebol can do 
this f g h - things, but i cant imagine code where i change the length 
of the argument-list and both versions have  usefull meaning. (except 
of shortening the list and relying on the "nop"-effect for the other 
args, but even that is risky.
parentese-once: func [code "at function-start" /local arglist pos 
out paren] [
    arglist: first get first code 
    pos: next code 
    out: reduce [first code] 
    loop length? arglist [
        either all [
            word? first pos 
            any-function? get/any first pos
        ] [
            set [paren pos] parentese-once pos 
            append/only out paren
        ] [
            append/only out first pos 
            pos: next pos
        ]
    ] 
    reduce [to-paren out pos]
] 
parentese: func [code /local paren out] [
    out: copy [] 
    while [not tail? code] [
        set [paren code] parentese-once code 
        append/only out paren
    ] 
    out
] 
ctx-tuneme: context [
    append: func [arg1] [arg1] 
    f: func [] [append 7 append add 5 6]
] 
ctx-tuneme/f ";run it once" 
probe parentese second get in ctx-tuneme 'f
I see no real problems with this
Pekr
15-May-2006
[745x2]
AGG 2.4 released - some things redesigned, it is major version update. 
It now allows to render Flash path curves data directly - http://www.antigrain.com/news/index.html
Does it mean we can use Flash IDE tools to do animations, save them 
as curves and then possibly render it using AGG 2.4 in View? :-)
Terry
15-May-2006
[747]
why bother?
Volker
15-May-2006
[748]
I guess there are svg->gflash-tools?
Pekr
15-May-2006
[749]
well, Terry - for those who like animations? We don't have any Authoring 
tools for view/draw yet ... so why not to be able to "play" some 
SVG or Flash vector data?
Volker
15-May-2006
[750]
Because Terry uses flash directly, which can render flash too ;)
Pekr
15-May-2006
[751x2]
.... and as View does not allow for media integration (I have heard 
it can change), so no avi, flash, etc. integrated, you can't use 
3rd party technologies with View stand-alone apps ...
Flash can render Flash? Never thought about using it in such an easy 
and direct way :-)
Volker
15-May-2006
[753]
But it could mean the other way around. 'draw -> flashcurves -> flash. 
The master of flash-dialect would be happy :)
Pekr
15-May-2006
[754]
hopefully Cyphre will bring 2.4 into View ......
Volker
15-May-2006
[755]
He mustbe very busy if he can resist :)
Henrik
15-May-2006
[756]
how much of AGG does DRAW take advantage of currently?
Pekr
15-May-2006
[757x3]
full?
IMO old draw C code was all replaced by AGG equivalent ...
... and for new Rebol (but Cyphre or Carl could confirm), IIRC someone 
said, even compositing engine will be replaced, just dunno if by 
the one in AGG ...
Henrik
15-May-2006
[760]
it would make sense if it was. it would make View a little smaller, 
wouldn't it?
Pekr
15-May-2006
[761x2]
not sure .... dunno how AGG is integrated, maybe AGG compositing 
is not used at all? Difficult to say ... but I expect radical redesign 
of View - at least we can be sure there is new event system placed 
inside, hopefully libevent .... so I expect even some compositing 
system changes and also face concept redesign ....
It would be nice if Carl would blog a bit about new View internals 
....
Henrik
15-May-2006
[763]
I hope there will be direct access to the buffer rather than going 
through SHOW. this would speed up operations immensly.
Pekr
15-May-2006
[764]
If Cyphre is in charge, I expect him to push Carl for more media 
features :-)
Henrik
15-May-2006
[765]
well, if he gets them through, it screams AmigaDE replacement, which 
can be a good thing right now
Pekr
15-May-2006
[766x2]
of course .... noone except few companies use AmigaDE ... AmigaDE 
(let's talk intent), has some powerfull media capabilities ...
.... but dunno, if today, being self-hosted, means an advantage - 
there is nowadays lot's of even small OSes Rebol can run on-top of. 
I prefer it being that way ....
JaimeVargas
15-May-2006
[768x2]
Volker, parentese fails in this case. The 
body of f didn't change 
as matter of fac t
it runs and produces as result 6. But the
parentese 
func fail to produce an expression 
for it. 



ctx-tuneme2: context [
    
	append: func [arg1] [arg1] 
    
	add: func[][none]
   
	 f: func [] [append 7 append add 5 6]

]



ctx-tuneme2/f ";run it once" 

probe parentese second get in ctx-tuneme2 'f


  ** Script Error: get expected word argument of type: any-word object 
  none

** Where: parentese-once

** Near: arglist: first get first code
So ctx-tuneme and ctx-tuneme2 has the exact same body for F..  However 
they perform different evaluations, one compiles another not. This 
is the problem. Now you can keep tuning parentese, but I bet it is 
always possible to find a way to break it.  The larger the body of 
F, the more posibilities for evaluation exists.
Volker
15-May-2006
[770x4]
No, that is a problem with an intentionally limited quick POC.
But i had to blink twice. :)

It currently expectes that all expressions start with a word. Now 
tuneme2 is  [(append 7) (append add) 5 6].
And it fails. As it should with this limited subset. 
Found it after adding a probe,
      arglist: first get probe first code 
which gave 5 on last run.

I do think  i can match rebol completely (means a rebol with small 
additions/restrictions).

Its as tricky as to compile, say 'c. There are lots of exceptions, 
but in the end it is possible.
Handling standalone values is one of the first thoughts of course. 
then there are operators and refinements. Then deciding if something 
is rebol-code or not (that needs an extension. 'do must flag it processed 
the block. So that parse-rules etc can be detected as data and the 
parens inside are detected as "run by do". Surely more small things, 
but should be doable.
Btw makes nice coverage-tests then)
http://www.cs.vu.nl/~ast/reliable-os/
Henrik
15-May-2006
[774]
volker, nice read. very easy to digest.
Volker
15-May-2006
[775x3]
Yes, Tanenbaum can write:)
Fission: https://addons.mozilla.org/firefox/1951/

Puts the progression-bar below the url (at the top, where one looks). 
Interesting feedback.
below means bar is now the url-background.
JaimeVargas
15-May-2006
[778x4]
Volker, I never say that compiling rebol is not possible, I said 
that is exponentially difficult.
So in practice compiling rebol is a pain in the arse.
Much more than other languages. Because there is no easy way to make 
assumptions. The moment you make an assumption you leave space for 
a compilation hole.
Now if the Rebol becomes a function first language like lisp you 
can get a bit further but still you will need some other markers.
Volker
15-May-2006
[782]
No, exactly not. Without that "run first" yes. With it not. Or i 
miss something very stupid.
Henrik
15-May-2006
[783]
MINIX3 sounds interesting, BTW.
Maxim
15-May-2006
[784]
I'm almost tempted to try it out  .... but I'd need time for that... 
 ;-)
Volker
15-May-2006
[785x2]
Thought that too. Small kernel, has X, would be a recompile.
There is a live-CD!!
Maxim
15-May-2006
[787]
it could be the basis for rebol/OS standalone appliance.
Volker
15-May-2006
[788x4]
-> recompile to run rebol.
Interesting nameclash :) http://www.cs.vu.nl/orca/. Found it by 
looking for Amoeba. "We cooperate intensively with the  Globe  group 
of  Andrew Tanenbaum ([ast-:-cs-:-vu-:-nl])."
(one of Tanenbaums distributed osses).
I like the bontago here. http://www.digipen.edu/main/Award_Winning_Games

To our physics: Is it possible to build a little physics-engine for 
such things, and how about collision-detection? The 3d from the contest 
could be sufficient for a small version of this.