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There are some text objects below the radio buttons [RS  S LS  M 
L], that can be dragged from their current location and moved anywhere 
on the layout, not just the drawing area.  These objects can be moved 
again at any point, and are not included in the overall draw dialect 
for the image area.

If I can blend these two functionalities into one, I'd have the best 
of both worlds.  Essentially I'm looking to build a Vector-like draw 
program, but as simple and small as possible.  This would allow drag 
points onto any selected object in order to allow for resizing or 
fine-tuning of object placement.  As I said previously, I believe 
Anton has done some work with drag-points on lines etc, but don't 
remember the script name that did this.  Warp-image.r also does something 
similar with an image.

I think this would be a very interesting project to undertake.  It 
would be nice to have both the smallest paint program, and vector 
drawing program in Rebol.

you can remove that line from the code, it's only used to save the 
draw data if you press the save button.  I should have removed any 
reference to the sqlite and the associated queries.

I used the method to drag-and-drop as used in Nick's Guitar Chords 
app.  It worked great for that type of drag and drop.

Hi, I'm starting with Rebol and I'm asking myself how to split a 
given string according to a pattern delimiter : "2 linebreaks or 
more" ?

The second argument to parse can be a string, and then parse split 
up the first argument, or the second argument can be a block of parsing 
rules. out is just my output block.

So the parsing rules go:
1) first any of a sub-block of sub-rules

2) sub-block copy the input string to a point, where two newlines 
are found, the result in the variable: arg

3) the paranthesis is evaluated (as normal REBOL code), and it append 
arg (the part of the string, we just copied) to the variable out
4) the parser then skip any number of newlines (2, 3 or more)

5) when the sub-rules are not valid any longer, the input string 
is copied till the end (and appended to out as before)

parse is ridiculously powerful (and equally hard to learn/use) :-)

kib, I think, you'll find performance of parse to be really good, 
and I think, the reason is, that parse is native.

Geomol: cool. And does parse uses Unicode with R3 now ?

I have some rather large paring rules here:
http://www.fys.ku.dk/~niclasen/nicomdoc/nicomdoc.r
http://www.fys.ku.dk/~niclasen/nicomdoc/ndmath.r
and it's very fast to create a huge document from those rules.

shadwolf: certainly, but it depends on what langage you're coding! 
Rebol seems a good candidate for such tasks. I'm also learning Factor, 
and I can tell you that it's a way harder (but maybe that's because 
it lacks some docs).

kib, after I parse the input to RebXML format, I parse the RebXML 
to HTML with: http://www.fys.ku.dk/~niclasen/nicomdoc/ndrebxml2html.r

So 2 huge sets of rules (3 with math) is into play, and the final 
document is there in a matter of seconds.

kib, so I find parse to be very fast, and this real example is a 
good showcase, I think.

kib2 yes because rebol concept relies on 2 things in fact objects 
and dialect and as dialects are linked to parse system parse is the 
real thing that makes rebol a different language

that means you can analyse each and every char in your document or 
locate flags and retrieve the data following

I should retake my svg engin and try to make it in full raw parse 
 ^^

I have more and more need for LaTeX output, so I might do it any 
day.

since R3 is not stable and official and that it can change alot until 
being stable so i don't write anything for R3

and once R3 is out i will do the efffort to restart from scratch 
this project and do it 1 pass pure parse

i would say parse is really the thing i need to understand further 
and heavy work on (you can write a 500  pages book only about parse 
and all it's subtilities)

I've been programming in Python for 6 years now. When I became fed 
up with it 3 months ago, I've tried maybe 15 langages since, and 
now I've got 2 or 3 good candidates.

good question and hum apart the one you will set yourself i don't 
know

Henrik: and you're self hosting ?

if i was president i would ban apach and impose cheyenne! :O

Janko: thanks. I'm starting and don't understand why this snippet 
does not work : http://clojurepastebin.appspot.com/1003

Most REBOL programmers use FUNC, and not FUNCTION, because it's easier. 
Let me see, if I can rewrite your function with func...

Geomol: I just followed the book I bought, it tells me that func 
uses globals, and globals may not be the best no ?

Examples of words, that get declared (defined or known from now on) 
and also get build:

a: none
b: 42
c: make block! 16


If you specify words to be local to a function, they don't get declared 
(build). It just mean, that when you refer to those words, they will 
be local to the function.

so

my-func: func [
	var1 var2
	/local var3 var4
][
.....
]


In this, var1 and var2 are two arguments to the function. var3 and 
var4 are treated local to the function, but they're not created yet.

Another version, you might find useful (at least to see how to make 
the same thing in different ways, and with different number of variables):

fibonacci: func [
	i
	/local a b
][
	set [a b] [1 1]
	 loop i [
		print a
		set [a b] reduce [b a + b]
	]
]

I said my book wasn't clear because in presenting blocks, it uses 
the words "arrays", then "lists" and "series" inside : it's quiet 
confusing.

I guess, words like "arrays" and "lists" are common in other languages. 
In REBOL, you'll see the word "series" a lot.

A block is a series of elements (inside [ and ]).

So what's the difference between a block and a serie ? A serie is 
a block for me no ? (the inverse may not be right)

not all series are alike. We tend to differ between strings and blocks 
and blocks come in a few different types, optimized for specific 
use, but they may hold the same content.

A computer language theorist might tell you differences between arrays, 
lists and series. I suggest, you take the practical view and look 
at what datatypes, you find in REBOL.

if we didn't have this many datatypes (R3 has even more), parsing 
and dialects would be less fun.

plus in R3 you can define your own and group types in new ways.

wow, you can make your own and combine.. that seems very good!

cool and powerful, but we've to wait until R3 gets more stable.

CONTEXT is a function, and you can see, what it does with:

>> source context

and objects are contexts. when wrapping set-word!s in contexts, they 
stay inside that context.

kib2, since you can bind contexts everywhere, even inside other contexts, 
they are not really secure and so you can't make things really private 
to a context. Modules will do that, I believe.

+ in this two cases "dispatches" on the type of arg... but this is 
probably handlede inside + , so if you define new type (vector3d) 
you couldn't make + work for that datatype too without changing it 
... in multiple dispatch + is a generic word and you add definitions 
for it for that datatype so it can work on them without changing 
or having access the original +  (basically similar to what is operator 
overloading at static lang, here it dispatches in runtime based on 
type)

Janko, I've been thinking about this problem too, and I'm not sure, 
what's best. Is it good enough, what we can do with functions today? 
Like:

>> old-add: :add

>> add: func [a b] [either string! = type? a [join a b] [old-add 
a b]]
>> add 4 5
== 9
>> add "Hi " "John"
== "Hi John"

Now ADD can also be used to join strings.

kib2, note: the web based dictionary is older and less updated than 
the word browser, but it works OK.

kib, to avoid confusion, remember that everything in REBOL is a word. 
The word in itself doesn't have a certain meaning. The words have 
meaning, when used in a context. The same word can mean different 
things in different contexts. And you can redefine everything, even 
things like: + and -

Geomol: something like you and I described would probably be possible 
to do in library , probably not that effective but it should surely 
be possible

I guess, a number like 1 can't be said to be a word, and it can't 
be redefined. But you can make a dialect, in which 1 means something 
else. So you have words, numbers, blocks, etc. The words can be redefined 
to suit your needs.

Geomol: That's really cool; data is code and vice versa, like in 
Lisp ?

Steeve : you don't have too. I'm playing with it at the moment (with 
R2), and I really enjoy it.

Janko: I like this, and in fact it's also the Factor way of doing 
things.

but quotations in factor are still more special case, you have curry 
and few words for them , but in rebol code block is the same as ordinary 
data block ( like a sequence { asdasd asd asasd } in factor so you 
can use insert append remove next ... etc on it .. I imagine factor 
is more limited here because it compiles things, here you can process 
your block of code just the same as data and then run it

I use that more too and it works.. I don't remember if I changed 
anything

hm.. it seems I just copied that file into .emacs and added 2 lines 
(I just started using emacs)

I saw there was a really nice postscript (and pdf) lib in Rebol. 
What about using it for making scientific diagrams ? (an old project 
of mine, in Python, was geoPyx here: http://kib2.free.fr/geoPyX/geoPyXfr.html)

When the interpreter evaluates some items in a block, and it comes 
across word!, it automatically tries to reduce it to its associated 
value.

In the classes in astronomy, we're taught a language called IDL to 
reduce scientific data and make images and diagrams. I often just 
use REBOL directly to make the diagrams. I've wanted many times to 
make a library of routines or a plotting application in REBOL, but 
haven't had the time yet. Maybe some day.

and
>> reduce reduce ['a]

kib, it's probably not hard, maybe take a bit of work to make it 
really slim and clever. I just have a ton of projects in the air 
all the time, so I didn't come to it yet.

DO is like REDUCE, in that it evaluates every item in the block, 
except DO does not create and store results in a new block - it just 
returns the last value.

The 2 is evaluated (to 2), then the 3 is evaluated and returned, 
because it's last.

Remember, if you wanna know more about operators like =, == and =?, 
just use ? to ask about them:

>> ? =?

Geomol: in the last case 1 and 1.0 are different beasts because the 
first is integer and not the other, that's it ?

kib, yes. == wants both to be same value and same datatype.

http://www.fys.ku.dk/~niclasen/rebol/libs/math/complex.r

Just a little start, and no documentation, so you have to read the 
code to figure it out.

Geomol if your memory works like mine, you only remember process 
and structures not contents

i meant ie is there something for computing intersection between 
a line and a bezier path ?

kib, no there isn't much graphic routines in postscript, just box, 
boxfill, image and line:
http://www.fys.ku.dk/~niclasen/postscript/postscript.html

kib2, you mean intersection(s)* between a line and a bezier path.

kib, I took a look at the PS documentation, and it has arcs, curves, 
etc. This isn't implemented in the REBOL ps dialect (yet). My dialect 
was just make fast to get some useful postscript out from REBOL.


I have a book on computer graphics, that might deal with the problem, 
you describe. I take a look ...

I would not rest until I had computed the exact intersection(s) of 
line and bezier curve ! :)

Let's see, chapter 7, "Intersection in 2D". "7.3 Linear Components 
and Quadratic Curves", "7.4 Linear Components and Polynomial Curves". 
Hmm

The book is called "Geometric Tools for Computer Graphics" by Philip 
J. Schneider and David H. Eberly.

I think, it's an excellent book. I read about it on the web long 
ago, people discussing different books dealing with geometrical problems 
in computer graphics. I bought it back then and have used it often 
since.

Chapter 7.4 starts with "This section discusses how to compute points 
of intersection between the line and curve from both an algebraic 
and geometric perspective."

Taking some time to read and understand the chapter, I would guess, 
it wouldn't be too hard to construct an algorithm, that did the job.

Game developers have solved many such problems, and often in efficient 
ways (games like performance). Intersections with Bezier curves are 
discussed here:
http://www.gamedev.net/community/forums/topic.asp?topic_id=385751

Steeve :  the purpose is to create a geometrical drawing dialect. 
Maybe I'll have a line (AB) that intersects an ellipsis and I wanted 
to use the intersection points

.. because this is where I step in:

http://anton.wildit.net.au/rebol/gfx/demo-intersection-points-of-line-and-ellipse.r

http://anton.wildit.net.au/rebol/gfx/demo-intersection-points-of-line-and-circle.r

LOL again! I was just about to say:


ah, intersection of a line and an ellipse, then you just have to 
go to Anton's library.

Anton, that's a really cool demo with the line and ellipse!

And I can move the ellipse and endpoints of line around. Cool!

About intersect of line and polynomial curve.
There's a preview of the book, I was talking about here:

http://books.google.com/books?id=82kntxqd1BoC&printsec=frontcover&dq=Geometric+Tools+for+Computer+Graphics#PPA250,M1

If you just wanna print the result, PRINT can work on a block, which 
will be reduced and spaces included in the output:

>> print ["Date:" now/date "Time:" now/time]
Date: 8-Feb-2009 Time: 23:24:27

For debugging, you'll find PROBE to be very usefull. You can put 
it in about anywhere in your code, and it will just work as without 
PROBE. Examples:

>> square-root probe 4 * 8
32
== 5.65685424949238
>> read probe join http:// "www.rebol.com"
http://www.rebol.com
connecting to: www.rebol.com
== {<html>
...

Geomol: and thanks a lot for your help

You have build-tag, to-tag and build-markup.

it is normal that hash! will only hash "keys" of assoc on first level, 
if you want on sublevels you can iterate the list and turn it into 
hashes acordingly .. if you have a lot of data hash is a lot faster 
650x in this test http://www.rebol.com/article/0020.html

Is there any tool to edit and view  at the same time rebDoc files 
? I've an idea...

kib, like "Easy VID"? Go to ViewTop and REBOL.com/Demos/Easy VID

When you read a page, you can click the code and see how it evaluate.

Geomol: I think so :) But for the moment it's in Python (and Qt4). 
Is there any browser-like widget in the Rebol GUI ?

great ! and can you make some parts of text to be bold or italics, 
etc ?

To make to look good with italic and bold text in the middle, you 
can use the function SIZE-TEXT to get the layout sizes.

I'm going to bed. Night! And happy coding! :-)

Yeah, DOC style is a good start.

But there are already great things with R2 : remembering HyperNotes 
(In R2 Desktop, rebol.com, Contest) this is a Makedoc based and rendering 
is just fine, with links and so on !!

But thanks, "halt" solved my problems as I can now launch my script 
from my editor and watch the Rebol's console output.

I would not trust R3's parse for now. It's buggy and changing.

ok, and for my paragraphs ?