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World: r3wp

[Rebol School] Rebol School

Janko
21-Mar-2010
[3065]
I know that rebol appeared to be the slowest language on debian language 
shootout , but then cheyenne is *much* faster webserver than any 
of the ones made in dynamic languages I tried (even lua). so speed 
is a relative thing it seems (like Brian says)
Henrik
21-Mar-2010
[3066]
also when using dialects, there is often a huge speed gain, but you 
can't really code like that in most other languages.
Davide
21-Mar-2010
[3067]
In this case, I think that  we can be happy with performance too.
Janko
13-Apr-2010
[3068]
Is there a way to pass a refinement further? so I don't have to do 
something like
do-some: func [ /ref ] [ either ref [ do-more/ref ] [ do-more ] ]
Ladislav
13-Apr-2010
[3069x2]
that is an oldie. In R3 as well as in R2+Rebcode you can use a native 
APPLY
otherwise you are mostly "out of luck"
Janko
13-Apr-2010
[3071]
aha, my r2 doesn't seem to have apply.. I will solve it some other 
way :) thanks
Ladislav
13-Apr-2010
[3072x2]
Well, the mezz. Apply may be quite slow, but if it suffices...
Then you can download it somewhere
Janko
13-Apr-2010
[3074]
I will use normal argument .. I don't want to further complicate 
codebase to make it a little nicer
Ladislav
13-Apr-2010
[3075]
http://www.rebol.org/view-script.r?script=apply.r
BrianH
14-Apr-2010
[3076]
There's an APPLY in R2/Forward that replicates R3's APPLY native. 
Either the native or the R2/Forward version will be in 2.7.8.
Maxim
14-Apr-2010
[3077x2]
janko, when I have chained calls which use options, I do this:

func [/opta /optb /options oblk][ 
	oblk: any [oblk copy [ ] ]
	if opta [append oblk 'opta]
	if optb [append oblk 'optb]

	; then use the block exclusively using find.
	if find oblk 'opta [print "option A supplied"
	if find oblk 'optb [print "option B supplied"

	; this way you can easily chain options 
	do-something/options oblk
]
oops... missing end "]" chars ... you know where.
Gregg
14-Apr-2010
[3079]
I've done the same thing as Max, and if there is just one refinement, 
I'll still use EITHER. If you have a scenario where there's an entry 
point that delegates work and requires multiple options, consider 
making it a dialected func.
BrianH
14-Apr-2010
[3080x3]
The APPLY mezzanine in 2.7.7 has a minor, obscure bug that is fixed 
in a later R2/Forward release, and later R2 mezzanine source. But 
aside from that it works fine, and I have used it in production code 
with no errors (the bug was so obscure that it never came up in practice 
or testing).
Maxim, you forgot to copy oblk.
Without APPLY or something like it, you end up having to do some 
tricky stuff sometimes. See this REMOLD backport for instance:

remold: func [
	"Reduces and converts a value to a REBOL-readable string."
	value [any-type!] "The value to reduce and mold"
	/only "For a block value, mold only its contents, no outer []"
	/all "Mold in serialized format"
	/flat "No indentation"
][ ; Nasty, but the best you can do without native APPLY
	do pick pick pick [[[
		[mold reduce :value]
		[mold/flat reduce :value]
	] [
		[mold/all reduce :value]
		[mold/all/flat reduce :value]
	]] [[
		[mold/only reduce :value]
		[mold/only/flat reduce :value]
	] [
		[mold/only/all reduce :value]
		[mold/only/all/flat reduce :value]
	]]] not only not all not flat
]
; Note: Uses APPLY in R3.
Maxim
14-Apr-2010
[3083]
good catch on the copy
BrianH
14-Apr-2010
[3084]
And that REMOLD should be using get/any 'value instead of :value 
- an R3-ism that crept into the code.
Maxim
14-Apr-2010
[3085]
is get/any 'value faster?
BrianH
14-Apr-2010
[3086]
No, but it supports molding unset! values and errors.
Maxim
14-Apr-2010
[3087]
ok, thought that was the reason
BrianH
14-Apr-2010
[3088]
In R3 :value supports that - it means GET/any instead of GET.
Maxim
14-Apr-2010
[3089]
cool! its easy to trip R2 when scanning blocks and an unset! value 
lies there
BrianH
14-Apr-2010
[3090x2]
We did a *lot* to make R3 easier and more powerful :)
Nevermind, I think the [any-type!] in R3's REMOLD is the error, not 
the :value in the backport. I'll fix it now and put in a ticket.
Steeve
14-Apr-2010
[3092]
See my beloved version :)

remoldx: func [x /all /flat /only][
	do head clear change change change next 'mold/?
		pick [[] all] not all
		pick [[] flat] not flat
		pick [[] only] not only
		reduce x
]
BrianH
14-Apr-2010
[3093]
You forgot to copy 'mold/? :)
Steeve
14-Apr-2010
[3094]
no, it doesn't matter
because of the clear
BrianH
14-Apr-2010
[3095]
The clear clears the end, since that is what CHANGE returns, so it 
has no effect.
Steeve
14-Apr-2010
[3096x2]
it has an efffect because the path is modified inside the source 
after each call
but i have not tested without clear
BrianH
14-Apr-2010
[3098x2]
Yes, but at the position the CLEAR is in the source, it has no effect. 
The modifications to the path persist.
>> source remoldx
remoldx: make function! [[x /all /flat /only][
    do head clear change change change next 'mold/?
    pick [[] all] not all
    pick [[] flat] not flat
    pick [[] only] not only
    reduce x
]]
>> remoldx/all/flat/only [1 2 3]
== [1 2 3]

>> source remoldx
remoldx: make function! [[x /all /flat /only][
    do head clear change change change next 'mold/all/flat/only
    pick [[] all] not all
    pick [[] flat] not flat
    pick [[] only] not only
    reduce x
]]
Steeve
14-Apr-2010
[3100]
i tried without 'clear just now, and as I thought, it's broken right 
now
BrianH
14-Apr-2010
[3101x2]
I tried with clear just now, and it was broken.
As demonstrated above.
Steeve
14-Apr-2010
[3103]
works well here, try a probe
Are you trying with R2 ?
It's not working with R3

remoldx: func [x /all /flat /only][
	do probe head clear change change change next 'mold/?
		pick [[] all] not all
		pick [[] flat] not flat
		pick [[] only] not only
		reduce x
]

probe remoldx/all [next 'a/a 2] 
probe remoldx/all/flat [next 'a/a 2]
probe remoldx [next 'a/a 2]
probe remoldx/only/all/flat [next 'a/a 2]

>>

mold/all
[#[path![a a]2] 2]
mold/all/flat
[#[path![a a]2] 2]
mold
[a 2]
mold/all/flat/only
#[path![a a]2] 2
BrianH
14-Apr-2010
[3104x2]
Just traced through, and the changes are persistent but the clear 
cleans up any extras. So it works from the outside, though it's not 
recursion-safe in R2 or R3, and not task-safe in R3.
The APPLY mezzanine uses a similar method (building a path), but 
creates a new path every time to be recursion-safe.
Steeve
14-Apr-2010
[3106x8]
Weird one :)

remold: func [x /all /flat /only][

 do head remove-each ref next copy 'mold/all/flat/only [not get in 
 bind? 'x ref] reduce x
]
Jeez , I don't need of the bind stuff...

remoldx: func [x /all /flat /only][

 do probe remove-each ref copy 'mold/all/flat/only [not get ref] reduce 
 x
]
I like this one, short.......
oups, i let the probe, even shorter.....
I didn't know, that even the refinements was bound to the context 
of the main function.
I meant the words in the path
I meant the words in the path
Well, It's needed when the paths are calculated (forget what I said)
BrianH
14-Apr-2010
[3114]
Nice. In R3 you'll need a temporary variable for the copied path 
because REMOVE-EACH returns the count removed instead of the value.