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World: r3wp

[Core] Discuss core issues

Maxim
18-May-2010
[16794x4]
if an application allocates and reserves 2GB I really don't care 
if its only using 10mb of it... my system is clogged and its not 
the OS's fault.
though I did a special of XP install which forces the OS NEVER to 
swap... and XP tends to be MUCH smoother because of it.
(special install of XP)  playing around with some obscure registry 
keys.
though for these tests, no swapping occured.
Henrik
18-May-2010
[16798x2]
I recently watched a talk by Poul Henning Kamp, author of Varnish, 
who talked about how many people misunderstand how memory allocation 
works in modern OS'es. Since he's a FreeBSD kernel developer, he 
has some bias, but he made some interesting points in that memory 
allocation is nearly free in various unixes, but most people ignore 
that an only allocate, perhaps just enough or below what they need.
Whether this can be translated directly to REBOL, I don't know.
Maxim
18-May-2010
[16800]
problem is when you task switch, or run several RAM intensive apps... 
they do kill each other, even on unix.
Henrik
18-May-2010
[16801]
but that's because the RAM is actually used, correct?
Maxim
18-May-2010
[16802x2]
(based on rendering 3D animations which required 4GB of swap file 
, just to load a scene  ;-)
yes... but as long as only one application is running the CPU, you 
can have A LOT of apps in virtual RAM without real system slow down 
(on unix).
Henrik
18-May-2010
[16804x2]
I guess I'm wrong with Windows. allocating a 100 MB string takes 
time.
takes even longer under OSX.
Tomc
20-May-2010
[16806x3]
while[here: find/skip here key 2][insert tail result second here 
here: at here 2]
rebol0  (untried)   suspect  parse is more efficent
ahh party moved to profileing and it has all been done
Pekr
20-May-2010
[16809x2]
For more precise system usage under Windows, please use SysInternals 
tools (now part of MS)
http://technet.microsoft.com/en-us/sysinternals/default.aspx... 
look at RAM Map, Process Manager, etc.
Terry
20-May-2010
[16811x2]
Q. how to use a word as a string value in path?
ie: ["a" 1 "b" 2]
n: "b"
ie/(n)
>> 2
nvm
Claude
20-May-2010
[16813x2]
very strange    a: true      logic? a  => true
but a:[true]  logic? a/1 => false
Sunanda
20-May-2010
[16815]
That's because [true] is a word, not a value. Try this:
     a: reduce [true]  logic? a/1  >> true
Claude
20-May-2010
[16816]
oki thanks
Terry
24-May-2010
[16817x2]
What's the advantage of using words in blocks? 
ie: [a "one b "two] vs ie2: ["a" "one" "b" "two"]
seeing you run out global word space very quickly?
Henrik
24-May-2010
[16819]
dialects and selection
Terry
24-May-2010
[16820x2]
ie2/("a")
>> "one"
so dialects then?
Pekr
24-May-2010
[16822]
yes, and the code readability maybe - ie2/("a") vs ie2/a
Henrik
24-May-2010
[16823]
using words as table keys is probably not a good idea.
Pekr
24-May-2010
[16824]
why? because of word limit? or any other consequences?
Henrik
24-May-2010
[16825]
limit, forbidden chars, etc.
Ladislav
24-May-2010
[16826x3]
word comparison is faster than string comparison
(word comparison is O(1), while string comparison is O(n))
moreover, words have context, strings don't
Geomol
24-May-2010
[16829]
Is it a benefit, that SWITCH is case insensitive?

>> s: "aA"
== "aA"
>> switch s/1 [#"A" [print "A"] #"a" [print "a"]]
A
Steeve
24-May-2010
[16830]
use strings not chars
Gregg
24-May-2010
[16831x2]
On words in blocks, if you use strings they may be duplicated as 
you copy blocks, which words aren't.
On SWITCH, I think it's consistent with REBOL in general.
Geomol
24-May-2010
[16833x3]
Steeve, no, doesn't work with strings:

>> switch s/1 ["A" [print "A"] "a" [print "a"]]
== none

s/1 is a char! And SWITCH won't find it with a string.
Gregg, "consistent"? Ahh... ;)


I was thinking about changing the string into a binary. What would 
you think FIRST used on a binary returns? I would expect a binary, 
but it's actually an integer. I sometimes have a hard time seeing 
the consistency in REBOL. But I know, it's hard to find the logic 
way in all this. So many datatypes. :)
Also changing s/1 to a string gives unwanted result:

>> s
== "aA"
>> switch to string! s/1 ["A" [print "A"] "a" [print "a"]]
A


So I end up with getting the integer value of a char to make this 
work:

>> switch to integer! s/1 [65 [print "A"] 97 [print "a"]]
a

Not so good, as I see it.
Steeve
24-May-2010
[16836x2]
Ah! it's probably impossible to convert a char! into a string!, so 
forget it...
hmmm. I just realized that you asked for insensitive case
Geomol
24-May-2010
[16838x2]
Yes, I need to test on chars in a string, and #"a" should be different 
from #"A".
The only way using SWITCH, I see, is to operate with ascii values, 
and that isn't good.
Steeve
24-May-2010
[16840]
well, just use parse instead, its mostly the same structure than 
a switch.

parse/case s [
	#"A" (do something)
           | #"a" (...)
           | ...
]
Geomol
24-May-2010
[16841]
Yes, parse can be used. My motivation was thoughts about switch. 
It seems, it could be improved.
Andreas
24-May-2010
[16842x2]
REBOL3 is pretty consistently case-ignorant in this regard:
>> #"a" = #"A"
== true