World: r3wp

>> 1 = 1.0  
== true
>> 1 == 1.0
== false

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

>> ? =?

It's fun doing these REBOL School sessions. It helps refresh the 
memories of us more experienced coders. It's hard (impossible) to 
remember all the corners of REBOL.

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

Can we use complex numbers ?

REBOL is like a little magical mountain lake. It doesn't look much 
on the surface, but it's soo deep.

yes Kib2 but the doc is incomplete, == is also case sensitive
>>"a" = "A"
==true
>>"a" == "A"
==false

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

kib, you can implement complex numbers as two numbers inside a block.

or should i say, = is not case sensitive

kib, I've made a little library for complex numbers, if you like.

Geomol: I don't need them for starting, but maybe I'll have to use 
them later on. Where is it located ?

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.

is there something in Rebol.org also ?

Geomol: thanks, no problem for the doc. Reading your code is the 
same.

Geomol: are you the author of the postscript dialect ?

yes

whao...

So i have a difficult question : how do you handle intersection(s) 
between two paths ?

kib2: Note well.  
	either 0 [true][false]  ;== true
	either 1 [true][false]  ;== true

hence:
	either (modulo malong 2) [true][false]  ; == true, always...

kib, :-D
Do you expect me to remember, how postscript works. ;-)
I have to think a bit now ...

ahah

kib, I think, I remember the concept of paths in postscript. Can 
you give an example of such an intersection?

you're like me Geomol, after some months, my memory is garbage collected

LOL yes

I try to remember the really important things, the rest just hit 
the bin.

kib2: you can write:
	either (1 = modulo malong 2) [true][false]

In rebol, 0 is equivalent to true, not to false (as in many other 
languages).

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

you remember abstract shapes, not data

well, I also remember data. I try to remember the important data.

like the greek alphabet. Doh! ;-)

all is data but the most important ones are data which build other 
data (rules) like in an inference engine

yes

Geomol: sorry, ....baby crying

Better to remember where do look something up, than to remember all 
that is in the book.

kib, np

exactly

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

better to know how to use a search engine (like google) instead of 
trying to remember all the url ;-)

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

I have to check the original PostScript documentation to say, if 
those things are part of the definition of PS.

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

Anton: yes, I've forgotten the (s)

It must be a fairly complex algorithm..

Anton: yes, that's why I was asking if someone else already wrote 
something like that. Computing such things much be a real headache 
!

if i had to do, i will use the draw engine with logical bitmap operators 
to find the points

it would be not really accurate but it would work

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 ...