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World: r3wp

[Core] Discuss core issues

Ladislav
17-Mar-2011
[1094]
:-D you need to consult the MY-CODE-A block contents
Rebolek
17-Mar-2011
[1095]
Because oit's different A
Ladislav
17-Mar-2011
[1096]
(or, be careful, and use the copy [...] construct)
Geocaching
17-Mar-2011
[1097]
Rebolek: both calls to 'a are in the same context (root context) 
How could we have two different 'a in the same context?
Ladislav
17-Mar-2011
[1098x2]
The variable is not different, Francois, but the blocks are
it's like

a: []
a: [1 2 3]


how come? that after no insert at all I get three elements in an 
(originally empty block? ;-)
Geocaching
17-Mar-2011
[1100]
Sorry... i do not understand...
 
>> a
== []

>> a
== [x x x]
Ladislav
17-Mar-2011
[1101]
>> my-code-a: [a: [] append a 'x]
== [a: [] append a 'x]
>> do my-code-a
== [x]
>> do my-code-a
== [x x]
>> a: []
== []
>> my-code-a
== [a: [x x] append a 'x]
>> do my-code-a
== [x x x]
>> a
== [x x x]
Rebolek
17-Mar-2011
[1102]
The first A is defined inside MY-CODE-A block. And because you do 
not use copy [], it's not rewritten every time you call MY-CODE-A 
block.
Geocaching
17-Mar-2011
[1103]
OK... it is a quiestion of pointer assignement in some way...
Ladislav
17-Mar-2011
[1104x2]
why pointer? by doing my-code: [a: [x x]] I just assign the block 
that is the second in MY-CODE to A
same? a second my-code
== true
Geocaching
17-Mar-2011
[1106]
It looks to me like everytime you call my-code-a, you assign the 
block defined in my-code-a to the variable a which is globally accessible. 
When you write a: [] outside my-code-a, you assigne another block 
to a... a is a pointer and you swith the adresse it is pointed to.

>> my-code-a: [a: [] append a 'x]
== [a: [] append a 'x]
>> do my-code-a
== [x]
>> a
== [x]
>> a: copy []
== []
>> append a 'y
== [y]
>> a
== [y]
>> do my-code-a
== [x x]
>> a
== [x x]
Ladislav
17-Mar-2011
[1107x3]
To explain it even futher, here is yet another example:

>> my-code-c: [a: []]
== [a: []]
>> do my-code-c
== []
>> append a 'x
== [x]
>> my-code-c
== [a: [x]]
hope, it is clear what is going on
just forget about pointers, please
Geocaching
17-Mar-2011
[1110]
sorry... C bad habits :)
Ladislav
17-Mar-2011
[1111]
Example prolonged:

>> my-code-c: [a: []]
== [a: []]
>> do my-code-c
== []
>> append a 'x
== [x]
>> my-code-c
== [a: [x]]
>> a: []
== []
>> my-code-c
== [a: [x]]
Geocaching
17-Mar-2011
[1112]
thanks ladislav... i got it!!!
Ladislav
17-Mar-2011
[1113]
An even longer one:

>> my-code-c: [a: []]
== [a: []]
>> my-code-d: [a: []]
== [a: []]
>> do my-code-c
== []
>> append a 'a
== [a]
>> my-code-c
== [a: [a]]
>> my-code-d
== [a: []]
>> do my-code-d
== []
>> append a 'c
== [c]
>> my-code-c
== [a: [a]]
>> my-code-d
== [a: [c]]
Endo
17-Mar-2011
[1114x2]
Why core doesn't support clipboard port?
Oh, I just find it is already in RAMBO.
BrianH
17-Mar-2011
[1116]
Consistency between OS platforms. On platforms other than Windows, 
/Core doesn't need X or any other kind of GUI, and so doesn't require 
the libraries (good for headless servers). When there is no GUI, 
there is no clipboard. The Windows version of R2 just inherited this.
Gregg
17-Mar-2011
[1117]
you assign the block defined in my-code-a to the variable a


In addition to not thinking in terms of pointers, the REBOLish view 
of the above would be "You set the word a to refer to the block defined 
in my-code-a"; words refer to values, values are not assigned to 
words. An important distinction.
Ladislav
18-Mar-2011
[1118x3]
I would like to disagree in this case. Not that it is important, 
but, in my opinion, the expression

    a: []


can be considered "assignment", whatever that means. In that sense, 
the value is "assigned" to a variable.
What is more curious in the "You set the word a to refer to the block 
defined in my-code-a" is the word "defined". The truth is, that MY-CODE-A 
is a block, that is created by the LOAD function at (roughly) the 
same time its contents, including the above mentioned subblock, come 
into existence.
What I wanted to tell was, that while the source string defined the 
subblock, as well as the MY-CODE-A block, the MY-CODE-A block only 
happens to actually contain (refer to) it.
Dockimbel
19-Mar-2011
[1121x5]
Just spent the last hour searching for the cause of an issue in my 
code. It appears to be a native LOAD bug, as shown by the code below:

>> length? probe load "[<] b [>]"
[<] b [>]
== 1
(I've reduced the use-case to its minimal form)
Seems that there's a shorter form that has the same issue: "[<][>]""[<][>]"
Sorry (paste duplicate), I meant: "[<][>]"
Just added a ticket in RAMBO, now need to find a workaround.
BrianH
19-Mar-2011
[1126]
Yeah, I remember that one from a couple years ago. The arrow words 
are special cased, and in R2 the tag type is recognized with higher 
priority unless there is a space afterwards.
Dockimbel
19-Mar-2011
[1127]
Right, this one is working: 
>> load "[< ][>]"
== [[<] [>]
]
BrianH
19-Mar-2011
[1128x2]
It's fixed in R3, so the fix needs to be backported. The main problem 
is that this code is output by MOLD.
>> mold [< ]
== "[<]"
Dockimbel
19-Mar-2011
[1130]
Nasty one.
BrianH
19-Mar-2011
[1131x2]
There are some bugs that are so bad that no backwards compatibility 
rule should apply no matter what.
I wish that the syntax precedence rules could be published so we 
can debug them, but apparently the loader is hand coded. I am trying 
to document them through reverse engineering.
Dockimbel
19-Mar-2011
[1133]
That would help!
BrianH
19-Mar-2011
[1134]
I already did this for word syntax for R3, and the process led to 
some bug reports.
Dockimbel
19-Mar-2011
[1135]
That's the second native bug I hit today...This morning while searching 
about an issue in Cheyenne's CGI handling (reported by PeterWood), 
I found out that the REBOL's CGI output in binary-mode is not working 
(it stays in string-mode, so corrupts binary data).


Is this the correct way to switch the CGI output to binary mode?: 
set-modes system/ports/output [binary: true]
BrianH
19-Mar-2011
[1136x2]
I thought CGI required WRITE-IO for binary output.
In R2 at least.
Dockimbel
19-Mar-2011
[1138x2]
I've tested both with INSERT and WRITE-IO, same result. But I've 
used CALL/OUTPUT on the test CGI script to simulate a call from a 
webserver.
Here's my test script: 
#!c:\dev\sdk\tools\rebol.exe  --cgi
REBOL []

print "Content-Type: application/octet-stream^/"
port: system/ports/output
set-modes port [binary: true]
insert port #{0D}
Andreas
19-Mar-2011
[1140]
it's probably the PRINT that is corrupting
Dockimbel
19-Mar-2011
[1141]
If you try to CALL/OUTPUT this script from 2.7.8, it will just freeze 
your REBOL session.
Andreas
19-Mar-2011
[1142]
try using `prin rejoin [... crlf crlf]`
Dockimbel
19-Mar-2011
[1143]
Testing that...