World: r4wp

I copied this from the documentation: http://static.red-lang.org/red-system-specs.html#section-4.8
paragraph 4.8.3 Dereferencing

Yes, but the C code is not dereferencing the pointer there; it's 
initialising the pointer

The example in 4.8.8 is what you need

http://static.red-lang.org/red-system-specs.html#section-4.8.8

Yes, in one way or another this is a trick to check if the initialisation 
step already has been performed. Hopelessly overcomplicated if you 
ask me.

It's confusing, yes, but it's typical C code. And it's by the holy 
Knuth, so you can't question it ;-)

Time for the Red rebolution to improve the readability of software.

I have been playing with the Mersenne Twister code, from C to Red/System. 
There is no unsigned integer in Red/System?

No, just integer!

If you use it as unsigned, you have to check very carefully what 
you're doing with the highest bit

Unsined integers is on the wish-list for Red/System v2 https://github.com/dockimbel/Red/wiki/Red-System-v2-Wish-List
point 29

You can always have an unsigned integer using a simple pointer.

Also, "unsigned" is just a convention, the data is same as the signed 
version.

As Kaj said, you can achieve the same calculation with signed integers, 
you just need to be careful.

one question for Red/System.  


can it already, ( or is it planned ) to export static libs for use 
within (C/C++, other?) compiler/linkers?

this would be an nice way for users to try red and progressively 
replace their binary code base, one source file at a time... instead 
of a whole project at once.

Yes, not yet, but it's in the roadmap. Currently, you can replace 
a project one shared library at a time, or one 0MQ service at a time

I have a new test pre-release version for Android, could some of 
you test it on different devices?

http://static.red-lang.org/hello2.apk

It should display an input field and a "Do" button, allowing you 
to evaluate arbitrary Red code. The result of evaluation scrolls 
up, below the button.

On Nexus4, it doesn't run. I would like to see how it reacts on other 
4.x devices and also older ones. It runs fine on my HTC 2.3.5.

On my Motorola XT881 running 4.1.2, Red opens and then immediately 
closes again.

Thanks Bo. Anyone with a 4.0.x device?

It runs fine on my Motorola ME525+ 2.3.6, but can't use PRINT, is 
that OK?

And on my ONDA Pad 4.1.1, it's opens and then immediately closes 
again.

The printing is redirected to the logcat. To see it, you need a logcat 
viewer like eLogcat from PlayStore.

I just remembered that I bought a few months ago a cheap Android 
4.1 USB stick, I will look at the 4.x issues tomorrow.

When we'll have a true Red console emulation for Android, we'll be 
able to redirect the printing functions back to the console.

The .apk wouldn't install on my Galaxy Nexus with 4.2.2.

Curious it installed on my N7

runs on my htc sensation 4.0.1

the only strange thing - the evaluator, when I mistakenly put: 1 
+ t = 1

Ah, so it's HTC-friendly it seems. :-)

t=0

I did not define 't, expected error being raised ...

so, it solved the equation! Pretty smart thing.

Actually, you got an error message sent to your logcat. :-) Once 
things will be stabilized for 4.x support, I'll redirect printing 
to the GUI.

It works on Samsung S3 Galaxy, Android 2.3.6

I've reproduced the 4.x issue on my Rikomagic USB stick.

Login on SO requires a OpenID account. Don't want to link all my 
info on the web. SO is over for me.

I don't have OpenID, yet I am using SO, is it really a necessity?

AFAIK you can create an account just for SO

I have an account on Wordpress.com lying around, even can login to 
Wpress, but SO says "You don't own that identity" :(

creating a separate account

The deobfuscating Knuth's random program project is progressing into 
its final stage. It turned out that with getting the results of the 
program the same only the first part of the puzzle got solved. To 
use it in real programs you use the provided ran_arr_next function. 
This involved some pointer aritmetic that is not 100%  supported 
by Red/System. I finally got the function to produce the same results 
as the C version. The downside is it is now quite a mess with pointer 
indeces and other variables, so a lot of cleaning up to do and/or 
rework only using the index on the array approach.

This involved some pointer aritmetic that is not 100%  supported 
by Red/System.
 What is it lacking precisely?

It is just slightly different. The possibility to go back to the 
first element of the array or store that address. :(ran_arr_buf/1) 
would make it a lot easier. 

I already had a lot of help from Peter on this (thumbs up!) and I 
made good progress by now.

I get the pointer of the array and I can go up and down  using + 
and -, this works great, and the pointer is going along with it then 
and I suspect that if I do 
ptr: ran_arr_buf 
and I progress ran_arr_buf by 1 that I progress ptr too.

I now kinda solved it by using an additional variable. When I reach 
a 100, I subtract 100 from the array ran_array_buf to go back. 

Tonight and tomorrow I have some time to clean up my code and I can 
experiment some more. 

It is proven it can be done, but keeping the extra variable is surely 
slowing down compared to C's pure pointer solution.

I suspect that if I do 
    ptr: ran_arr_buf 
and I progress ran_arr_buf 
by 1 that I progress ptr too.


That's a wrong assumption. Those two variables are distincts, so 
each one has its own memory slot. If you change one, that has no 
effect on the other. What is shared there is the pointed memory region. 
So, if you change ran_arr_buf/value, that will affect ptr/value (they 
both point to the same memory location).

my trouble seems to arise from the different roles the array and 
the pointer play in the C code vs the Red/System code. In C the pointer 
is used as indicator for initialisation and signals when a kind of 
reshuffle is required and it points to the next generated value. 
In Red/System the array points to the current/next value and a pointer 
is not needed, and you can no longer use it as before to signal the 
status. This complicates things in this case.

Oh nice effect. array1: 1 2 3 4 5 
m: 2
;;print array/m ;; 2
array1: array1 + 2
;;print array/m ;; 5

it is tricky to move the array pointer around, beware of the dog 
;)

sorry 5 has to be 4 in that example.

You seem quite confused about pointers in Red/System. 


1) There's no "array" as distinct entity in Red/System, but you have 
indexed access, so you can "simulate" arrays to some extent.


2) "In C the pointer is used as indicator for initialisation and 
signals when a kind of reshuffle is required and it points to the 
next generated value." I don't understand this sentence, you should 
stick to C terminology (terms like "signals", "reshuffle" and "generated 
value" are alien to me in a C language context).


3) "In Red/System the array points to the current/next value and 
a pointer is not needed, and you can no longer use it as before to 
signal the status." I don't understand this one either... There's 
no array, only pointers. "to signal the status" has no meaning to 
me...sorry.