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World: r4wp

[Rebol School] REBOL School

Kaj
13-Sep-2012
[976]
Hm, my Atari 8-bit already had that. I guess that's progress these 
days
Maxim
13-Sep-2012
[977]
I must admit that if you can receive events in the host, you can 
just execute a code string within the root ( just like if one enters 
a command in the prompt).   It worked very well for interfacing with 
GLUT ... I had just built a little pseudo event system which I called 
from within the glut callback and it was fast enough to handle all 
events in real-time.
Marco
16-Sep-2012
[978]
How can I convert an integer! that is a pointer to a C struct returned 
by a library function to a binary! ?
BrianH
16-Sep-2012
[979x2]
With more C code that copies the binary to a REBOL-allocated buffer. 
You can't deallocate a pointer in REBOL.
I mean dereference.
Gregg
16-Sep-2012
[981]
Will this work?

    LPINT-def: [value [integer!]] none
    LPINT: make struct! LPINT-def none

    make-LPINT: does [make struct! LPINT-def none]

    get-dereferenced-data: func [

        {Given a pointer to memory, copy the target data into a REBOL struct.}
        pointer [struct!]   "LPINT structure"

        struct-def [block!] "Contains a sub-struct that is the real struct 
        you want."
        /local struct data orig-pointer result
    ] [

        struct: make struct! compose/deep/only [ ; make wrapper struct
            sub [struct! (struct-def)]
        ] none

        orig-pointer: third struct              ; store original inner pointer

        change third struct third pointer       ; change inner pointer to 
        ref'd data

        data: copy third struct/sub             ; copy data from the inner 
        struct
        ;print mold data

        change third struct orig-pointer        ; restore inner pointer

        result: make struct! struct-def none    ; make result struct

        change third result data                ; change data in result struct
        ;probe result
        struct: data: orig-pointer: none
        ;recycle
        result
    ]

It's from some old code, so no guarantees.
Marco
16-Sep-2012
[982]
@BrianH I am writing in Rebol, I am not able to write C code.

@Gregg I need to pass an integer! to a function that converts it 
to a binary, and your function expects a struct! how do I change 
it?
Gregg
16-Sep-2012
[983x2]
Put the integer value in an LPINT struct.
That is, use make-LPINT, set the /value, and pass that.
Marco
16-Sep-2012
[985]
Ok, thanks.
Gregg
16-Sep-2012
[986]
Also, get-dereferenced-data maps the buffer into another REBOL struct. 
If you just want the binary data, you can adapt it not to do that.
Marco
16-Sep-2012
[987]
ok it seems to work. it becomes:

 integer-address: get-address "hello" ; function courtesy of Anton 
 Rolls
	pointer: make-LPINT
	pointer/value: integer-address
	probe third get-dereferenced-data pointer [l1 [int] l2 [int]]
Kaj
16-Sep-2012
[988x2]
In my 0MQ binding, I import the memory copying function from the 
C library:
http://rebol.esperconsultancy.nl/REBOL-2-ZeroMQ-binding/dir?ci=tip
Ladislav
16-Sep-2012
[990]
You can't deallocate a pointer in REBOL.

 - that is false, use the http://www.fm.tul.cz/~ladislav/rebol/library-utils.r
BrianH
16-Sep-2012
[991]
I meant defererence, but I'm sure you're right.
MagnussonC
18-Sep-2012
[992]
I read a file, line by line and want parts of each line in certain 
variables. First is an integer then a space and then a 3-4 character 
word then a space and then the rest of the line in a string. I guess 
there is no way like in Perl to match those variabels at once and 
put the value in numbered variables. I suppose I need to parse that 
line with something like (thru "a" copy b to "c") once for each variable 
(or perhaps first char with line/1)!?
MaxV
18-Sep-2012
[993x2]
Please put some example, you are a bit vague
Read this http://rebol2.blogspot.it/2012/05/text-extraction-with-parse.html
   ;-)
Maxim
18-Sep-2012
[995x3]
does this help?
--------------------------

a: {123 abcd bla blca bla
534 hged bla blca bla
947 ahg psogie rpgioseg seo[rgieh rpgiu}

digits: charset "0123456789"
letters: charset [#"A" - #"Z" #"a" - #"z"]
space: charset " "
data: complement charset "^/"
ctx: copy [ ]
parse/all a [
	some [
		copy id some digits
		space 
		copy var 3 4 letters
		space
		copy line-data some data
		; we have a match for all data, add it in our container

  ( append ctx copy reduce [  to-set-word rejoin [var "-" id]   line-data] 
  )
		"^/"
	]	
]

ctx: context ctx

probe ctx
obviously, this depends on the input data being pristine... 

if there are chances that the input isn't, then a bit more code would 
allow you to safely skip invalid lines.
I added a bit of processing to show how to use parse in order to 
actually do things beyond just match patterns.


note that the paren is at the end, once we have all data we want 
to match.  An error people often do is to start processing too soon.
MagnussonC
18-Sep-2012
[998]
Thank you both! Now I have something to work with. Didn't realize 
you could do parse complex like that.
Maxim
18-Sep-2012
[999]
believe me... this is very simple parsin   ;-)
Gabriele
19-Sep-2012
[1000]
Max... "copy reduce" ? :-)
MagnussonC
19-Sep-2012
[1001]
Haven't had time to try the above yet. It would be interesting to 
see more complex examples of parsing. No need to write it here, only 
if you can redirect me to any existing code online. The examples 
I have found seems simple, but maybe there are things implicated 
in those examples that I don't grasp ...
Maxim
19-Sep-2012
[1002]
gab... oh yeah... copy isn't needed there.... it just evolved that 
way  :-)
Gregg
19-Sep-2012
[1003]
Magnusson, have you looked at the REBOL manual that explains the 
parse grammar?
Ladislav
19-Sep-2012
[1004]
See also


http://en.wikibooks.org/wiki/REBOL_Programming/Language_Features/Parse/Parse_expressions
MagnussonC
20-Sep-2012
[1005]
Gregg, yes. Ladislav, I'll check that also. The example Maxim gave 
was more what I was looking for, I think. Haven't had time to test 
it yet. Thanks for the help..
NickD
23-Sep-2012
[1006]
There has to be something Rebol is doing beyond a simple language 
api to get level of security purported by Carl. 
What kind of pipes does it use?
Kaj
23-Sep-2012
[1007x2]
What kind of pipes do you have in mind?
There's nothing much special in REBOL regarding security
NickD
23-Sep-2012
[1009]
My misunderstanding then. I do not even know what 'pipes' are. I 
am posing the question on behalf of another. The question started 
based on the understanding from a conversation with Carl concerning 
the security benefits of AltMe and the once pending contract with 
the CIA.
Kaj
23-Sep-2012
[1010x5]
Pipes usually refer to network connections. The encryption that is 
usually employed there (SSL) is missing from many REBOL versions
Pipes can also refer to local connections between processes, but 
that's originally a Unix technology
AltME is secure for partly different reasons. We are told it employs 
encryption over the network, but we can't check that, because it's 
closed source
When AltME was introduces a decade ago, many communication systems 
were unencrypted, so it was good then. Like Lotus Notes at the time
It's also more secure because you run your own server, instead of 
handing your data to a provider. That's fundamental, as long as you 
keep the data safe on all AltME clients. Which is hard, because it's 
not encrypted on disk
NickD
23-Sep-2012
[1015]
Ah. Ok. Thanks so much
MarcS
3-Oct-2012
[1016x2]
does anyone have time to sanity check / comment on the style of the 
following script: http://0branch.com/highlight/snippets/rfunc.r?
(i left in a couple of examples to demonstrate usage)
Henrik
3-Oct-2012
[1018]
it's certainly quite clean looking. did not analyse the code yet.
MarcS
3-Oct-2012
[1019]
as the title suggests, it's a fudge
Ladislav
3-Oct-2012
[1020]
One immediate note:


the RFUNC function as it is written actually modifies its SPEC and 
CODE arguments (that may be OK, but should be mentioned)
MarcS
3-Oct-2012
[1021x2]
spec isn't modified
re: body, is "Function body to be augmented w/ recursion context" 
not clear? [if not, will add clarification]
Ladislav
3-Oct-2012
[1023x2]
Actually, the SPEC block *is* modified, but in a way that may not 
matter often
It might be better, though, to not modify it at all.
MarcS
3-Oct-2012
[1025]
what are you referring to?