World: r3wp

http://pastebin.com/eixcKrTQ

sorry about that. I don't know why it keeps doing that sometimes.

maybe there is a timeout on pastes

@Henrik, ok.

@Henrik, does it work now?

yes, I can see it.

ok

which button press shows the error? and which series?

@Henrik, it is not so much an error as that it doesn't do what it 
should do by design

so when I press SOON, it should advance the question 5 places ahead. 
The temp file shows it does.

the display shows a  series that didn't change

the same behavior happens for all of them.

I tried move/to ; move/skip and even tried backtracking with back 
at every button press, without luck

is one expected to click "Show Question" after clicking "Soon"?

@Henrik, yes. to get to see the other questions.

result-answer/text: " "
show result-answer


This will assign a new string to the TEXT facet of the RESULT-ANSWER 
face. What to be careful of here is that every time you pass that 
bit in the code, it is the exact same string (same memory location) 
and not a new string that gets assigned. That means that if something 
is put in there from another location, that memory location will 
no longer be empty, and the content will be shown in RESULT-ANSWER.

I'm not sure that's the problem here, though.

@Henrik, I see.  Is this normal coding or just rebol?

it is normal rebol :-)

you might use one trick - result-answer/text: copy " "

Try this in the console:

repeat i 5 [append [] i]

and see what happens.


You will see that it literally is that block at that memory location 
that is reused for APPEND.

which is a clever way for not needing to assign a word to a block 
to use it, even just temporarily.

so, if you type:




in the console, a string is really made. you don't need to assign 
it. you just have no way to reach it by reference, so it's now left 
in "oblivion" until the garbage collector picks it up.

therefore in this bit of code:

button-press?: layout [
        ; displays output for user interaction
        result-question: info " "
        result-answer: info " "


two separate strings are also made prior to the LAYOUT function even 
getting the block passed. Depending on how the code that manages 
the INFO faces initializes the face, those two strings can possibly 
be referenced.

@Henrik, wow!

@Henrik, so what is REBOL if  not call-by-reference?

@Pekr, will this work in light of Henrik's remarks?

@Pekr, what I mean to say is that will  the code be useful in the 
situation where all of my code seems to be relying on different programming 
paradigms?

todun -  I am not a good programmer, so difficult to say :-) But 
- many ppl get into some gotchas, when using REBOL. Btw - do you 
know, that subobjects (objects inside objects) are shared?

@Pekr, uhm. do you mean like the scope or something similar?

@Pekr, I'm actually a new programmer myself. But I didn't start with 
REBOL thus my confusion.

>> person: context [name: copy "" address: context [street: copy 
""]]
>> a: make person [name: "petr"]
>> probe a
make object! [
    name: "petr"
    address: make object! [
        street: ""
    ]
]
>> b: make person [name: "henrik"]
>> a/address/street: "petr's street"
== "petr's street"
>> probe a
make object! [
    name: "petr"
    address: make object! [
        street: "petr's street"
    ]
]
>> probe b
make object! [
    name: "henrik"
    address: make object! [
        street: "petr's street"
    ]
]

I mean - when you have a prototype object, which uses subobjects, 
those are shared between the clones ...

@Pekr, in this context, what is a prototype object?

todun, "call-by-reference" I will defer that question to someone 
who better knows programming terminology, than me.

@Henrik. ok

thanks all the same.

contexts... also a deep topic. objects in rebol are contexts. there 
are not really prototypes as any object can act as one.

@Henrik, I still am not sure what prototypes are. So REBOL uses a 
different structure called a CONTEXT and not an OBJECT?

try:

source context

Some object oriented programming languages use specially notated 
prototype objects, from which other objects can be created. REBOL 
does not. You simply have objects. Prototypes here would be only 
a concept that you use as a part of your program to discern a "mother" 
object from other objects.

@Henrik, so prototypes are nested objects and the fact rebol only 
deals in objects goes back to its homoiconicity?

I think not. The prototype is any object you inherit from ...

no, prototypes don't exist at all.

Following document might be a bit dated, but it still contains some 
usefull explanation of REBOL core concepts ... http://www.rebol.com/docs/core23/rebolcore.html

it's simpler than one might think:

if you have two objects, one made from the other:

a: make object! [num: 5]
b: make a [num: 7]


if you do this without showing this part to another person, that 
person can't tell which object came first, only that two objects, 
A and B exist in memory. so there are no real prototypes.

@Pekr, @Henrik, ok.

Henrik, I have to object. REBOL is prototype based. Any REBOL object/context 
is a prototype

Some object oriented programming languages use specially notated 
prototype objects, from which other objects can be created.

Those are not called prototypes; those are called classes