World: r3wp

I'm mising something here :

#!/usr/bin/rebol -q

REBOL [
    Title: "Tests with oo programming"
    Date: 26-Feb-2009
    Author: "Kib"
    File: "ooo1.r"
    Purpose: "nothing interesting"
]

son: make object! [
    parent: none
    name: "object b"
    get-parent: does [print parent]
]

mother: make object! [
    name: "object a"
    son-instance: make son [parent: self]
]

pony-mum: make mother []
print ["object name: " pony-mum/name]
print ["instance name: " pony-mum/son-instance/name]

print ["instance name:(other method) " pony-mum/son-instance/get-parent]

What's wrong with the last call ?

son-instance: make son [parent: self] 

self refers to son-instance

Graham : as i'm inside mother, self refers to a mother no ?

It looks like you're inside son-instance

mother: make object! [ name: "object a" myparent: self son-instance: 
make son [ parent: myparent ]]

>>it looks like you're inside son-instance


I don't understand why, sorry. I'm inside mother (I mean, when I 
write it "son-instance", but maybe it's a bad Python habit). 
 
mother: make object! [
    name: "object a"
    son-instance: make son [parent: self]
]

http://rebol.com/r3/docs/concepts/objects-self.html

you're creating a new object son-instance so self now refers to son-instance

You mean when I write "make son ..." I'm already inside the son object 
?

that may explain my problem

I think so.

ok: thanks !

Is there any lib somewhere to encode or decode a file to utf-8 ?

Test it:
>> son: context [parent: self]
>> son/parent = son
== true

You could do:

	mother: context [
		son: context compose [parent: (self)]
	]

so now

	>> mother/son/parent = mother
	== true

better idea :)

Oldes did some work with unicode, if I remember correctly.

Anton: hi! thanks a lot: what's the meaning of the parenthesis here 
?

The COMPOSE rebuilds the block, with anything in parens evaluated 
first.

So SELF will be evaluated before the second CONTEXT has a chance 
to see it.

But, if you're curious, you can always have a look yourself, using 
PROBE, eg:

	mother: context [son: context compose probe [parent: (self)]]

	mother: context [son: context probe compose [parent: (self)]]

mother: context [son: context probe compose [parent: (self)]]

etc..

ah...funny : nice example.

For the encoding, I was asking this because all my accented chars 
in HTML appear correctly but one, the "à".

Just move the probe from right to left to find out what's happening.

kib2, check rebol.org. I just did some quick searching.
http://www.rebol.org/view-script.r?script=utf8-encode.r
http://www.rebol.org/view-script.r?script=utf-8.r

Anton: thanks, exactly what I was looking for :)

Is it possible to draw something (lines, arrows, curves, etc) on 
top of buttons in a GUI app ?

view layout [button 200 "Button with graphics" effect [draw [line 
0x0 10x20 40x0 60x20]]]

Geomol: sorry, I should have said "on top of several buttons". 

See http://farm4.static.flickr.com/3664/3323050539_dbd72b61e8_o.png
where I want to draw lines between numbers.

view layout [origin 0 space 0 button 50x50 "1" button 50x50 "2" at 
0x0 box 50x100 effect [draw [line 0x0 30x20 0x60 40x100]]]

Extra: thank you!

will events pass through the box?

Henrik: I think so, why ?

:-) heh, prob. not. But I bet, kib can figure that out.

Don't you wanna interact the buttons with the mouse?

Geomol: yes with the mouse; in fact if you click on a number, i should 
draw all possible bridges (lines) coming from it.

When you have the box with the lines on top over all the buttons, 
you can't press them directly.

Your mouse button press will 'hit' the box with graphics.

Ok, thanks for the hints : I think I have to study VID events a little 
more than what I've already done.

I have a question on same?  Do the following:
a: "apple"
b: to-string 'apple
same? a b
== false


Why is that, they are both strings of the same length and datatype, 
just not created in the same way?

Good question : i really don't know. Moreover, a == b returns true.

I tried this too:
a: "apple"
b: "apple
same? a b
== false


Does same? mean that it is the same object, not that the contents 
are the same?

I found the answer,  It is ONLY if the two are the same object

I know that = compares values, == compares values and types. Same? 
is native, and the docs says "Returns TRUE if the values are identical".

same? means litterally the very same string.

same? is useful for identifying references.

Henrik: do you mean their location (via a pointer) ?

yes

it's not entirely like pointers, but BrianH can explain that much 
better than me.

>> a: "boo"            
== "boo"
>> b: reduce [a copy a]
== ["boo" "boo"]
>> same? b/1 a
== true
>> same? b/2 a
== false