• Home
  • Script library
  • AltME Archive
  • Mailing list
  • Articles Index
  • Site search
 

World: r4wp

[Rebol School] REBOL School

BrianH
11-Mar-2013
[1742]
Before you ask, the MAP-EACH fix is going in there too :)
GiuseppeC
13-Mar-2013
[1743x5]
I will help to make the new REBOL !
Until then I need your help:
I whish to re-learn REBOL from scratch starting from REBOL3
I have understood that until now I have looked to REBOL with the 
eye of the "old-style-programmer"
I apologize for avery stupid question I'll make in the following 
weeks/months.
Arnold
13-Mar-2013
[1748]
no stupid questions exist. Mostly more stupid not to ask them, as 
only then they can help you to understand.
Sunanda
13-Mar-2013
[1749]
SKIP's offset arg can take a pair!  -- Can someone show me an example 
of doing that?
GrahamC
13-Mar-2013
[1750]
that's for moving across a bitmap isn't it?
Sunanda
13-Mar-2013
[1751]
That's what I'd like to know :)
GrahamC
13-Mar-2013
[1752]
let me scan my source code
Sunanda
13-Mar-2013
[1753]
Also interested in usage example for TAKE/DEEP where the /deep can 
be a pair!
GrahamC
13-Mar-2013
[1754x2]
auto-crop-bitmap-text: func ["Returns a cropped image, or none if 
the input image was blank"
	image [image!] 
	/local region
][
	if region: find-bitmap-text-crop-region image [ 

  copy/part skip image region/1 region/2  ; return a cropped image
	]
]
not sure if that's what you're after
Sunanda
13-Mar-2013
[1756]
Thanks......I can see now how SKIP can work on an image bitmap
    img: to-image #{....plausible hex stream....}
    skip img 2x2


However, TAKE does not work on image bitmaps.....Are there other 
types of bitmap?
BrianH
13-Mar-2013
[1757]
The bitset type could be thought of as a one-dimensional bitmap of 
depth 1, but that's stretching the defitnition a little :)
Sunanda
14-Mar-2013
[1758]
:)
Is TAKE intended one day to work on image bitmaps?
Or is there another use for:
     TAKE/DEEP word 10x10
BrianH
14-Mar-2013
[1759]
No, because TAKE removes from the original, and that would change 
the dimensions of the original in the case on an image, assuming 
it's possible (you can't take a hole from the middle, for instance). 
So you mean COPY/part here.
Sunanda
14-Mar-2013
[1760]
My confusion is due to the help for TAKE saying the /DEEP arg can 
take a pair! -- So I was looking for a usage case.
BrianH
14-Mar-2013
[1761x2]
Well, maybe it was intended to work on image (if so, sorry). I'd 
have to review the R2/Forward code to be sure, since its version 
of TAKE would have replicated that. It's a really weird thing to 
do to an image though.
The R2/Forward TAKE makes reference to an image in its code, but 
not in its typespec. Weird. A bug?
Bo
14-Mar-2013
[1763]
BrianH: If I wanted to take a subsection of an image, why wouldn't 
it create a new image with just that subsection, and then replace 
the "taken" part in the old image with 0.0.0?  Or am I understanding 
the purpose of 'take incorrectly?
GiuseppeC
15-Mar-2013
[1764x2]
First question about REBOL(£):
Is there an article which explains how REBOL3 loads words in memory 
and how their are organized, stored, evaluated ?
Sunanda
16-Mar-2013
[1766]
Here's a starting point for such an article.....
   http://www.rebol.com/docs/expert-intro.html
BrianH
16-Mar-2013
[1767]
Bo, TAKE physically removes stuff, it doesn't leave a hole.
NickA
19-Mar-2013
[1768x2]
Has anyone worked with the Amazon aws services?  I'm not sure how 
to "Calculate an RFC 2104-compliant HMAC with the SHA256 hash algorithm" 
as described in step 8 on page 62 here:  http://awsdocs.s3.amazonaws.com/Associates/latest/prod-adv-api-dg.pdf
Just trying to look up prices based on SKU.  This is the string I 
have so far:


http://webservices.amazon.com/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=[mykey]&Operation=ItemLookup&ItemId=041554286915&IdType=SKU&Timestamp=2013-03-19T10:04:31Z&Signature=[this-is-what-I-need]
Gregg
19-Mar-2013
[1770]
Graham has, but hit github repo for it seems to be empty. Not sure 
where he has it posted now.
NickA
19-Mar-2013
[1771]
Thanks Gregg - I'll see what he knows :)
GrahamC
19-Mar-2013
[1772x2]
You can't yet because we can't calculate a sha256 .. we only have 
sha1
so, you'll have to use an external library to do that part
Bo
19-Mar-2013
[1774]
I'm looking into pitching a Rebol programming class to the community 
college here (I'd teach it).  I know of NickA's excellent tutorials. 
 What would you all suggest for a class text.
caelum
19-Mar-2013
[1775x2]
I found the 'Rebol for Dummies' book quite disappointing for my personal 
use, but it might be good as a course book though. It certainly covers 
a lot of ground quickly. I personally preferred Nick's video series 
http://re-bol.com/rebol.html.Somehow more interesting and easier 
to digest. Just my personal experience.
I also have 'Rebol. The Official Guide' which at 700+ pages is massive 
and way too much. Also, no graphics included, so I would not necessarily 
recommend that as an introductory course book.
Bo
19-Mar-2013
[1777]
Yes, I also have Rebol for Dummies, Rebol: The Official Guide, and 
just about every other Rebol book in print.

I'm currently leaning towards Nick's tutorials right now.
PeterWood
19-Mar-2013
[1778x2]
Is the class for new programmers or people new to programming?


If the latter, Olivier Auverlot's REBOL - A Programmer's Guide" might 
suffice.

Full disclosure - I translated the book from French to English.


The content of the book is a little dated by newer than Official 
and Dummies.
by -> but
caelum
19-Mar-2013
[1780]
After looking at 'Rebol for Dummies' again, that is what I'd recommend 
for a community college course. Even if a little dated.
NickA
19-Mar-2013
[1781x3]
Getting enough copies of the other books out there may be difficult.
@Graham - thank you, yes I'm aware we only have sha1.  It looks like 
OpenSSL, PolarSSL, MD5Deep, cryptlib, and a bunch of others are out 
there.  Have you used any successfully with AWS?
I wonder if the Saphirion guys have sha256 going.
GrahamC
20-Mar-2013
[1784]
The AWS functions I use have sha256 optional
Endo
20-Mar-2013
[1785x3]
Bo: There is Viktor Pavlu's "REBOL Essentials" in pdf form.
Here is the link: http://vpavlu.plain.at/REBOL/tutorial/
There is a beginner's level View/VID part too.
Bo
20-Mar-2013
[1788x2]
PeterWood, caelum and Endo: Thanks for the ideas.  I've seen Olivier's 
book, but I don't have a copy myself.  That might be a good choice.
The book by Viktor Pavlu looks promising.
Arnold
21-Mar-2013
[1790]
I used that to get really more familiar with REBOL. It is a good 
introduction, unfortunately it is not finished. The up-to-date is 
less bothering for it is the basics that's covered and those are 
the same still.
Maxim
21-Mar-2013
[1791]
Olivier's book is pretty good IIRC.