AltME groups: search

You can build that singleton when rfunc is called initially, or if 
you only need one then you can use funct/with to make a static local 
var with that value. (Still haven't analyzed the source.)

another contribution:
	use [count inc start end op][
		count: inc: start: end: op: 0	
		in-range: func [
			[catch]
			'word [word!]
			start [number!]
			end [number!]
			/bump step [number!]
			/local result
			] [
			if inc = 0 [

    if step = 0 [throw make error! "step parameter cannot be = 0"]
				count: start

    either start > end [inc: -1 op: :greater-or-equal?][inc: 1 op: :lesser-or-equal?]
				unless none? step [inc: step]
			]
			set word count

   result: either op count end [count: (get word) + inc true][false]
			if not result [count: inc: start: end: op: 0]
			result
		]
	]
	i: 0 ; define a var
	while [in-range i 1 3] [print i]

Here's my first attempt at a pattern for recursion-safe temporaries:


use [var ...] [rule ...] ==> (tmp1: use [var ...] copy/deep [[rule 
...]]) tmp1


It would only work with a directly specified variable and rule block, 
and you should only use the temporaries directly in the rule block 
or they won't get rebound. Now, using REBOL 3's closure (probably 
better):


use [var ...] [rule ...] ==> (tmp1: do closure [/local var ...] [[rule 
...]]) tmp1


Of course this is just an example. An actual rewrite engine would 
premake the closure and insert it directly instead of making it in 
the rule and doing it. REBOL's existing function recursion support 
wouldn't work because the function returns before the rule is run.


I would prefer a native implementation of this operation if possible.

I show you something from my article:

a: b: charset [#"a" #"b"] c: insert charset [#"a"] #"b
identical?: func [
    {are the values identical?}
    a [any-type!]
    b [any-type!]
    /local var var2
] [
    ; compare types

    if not-equal? type? get/any 'a type? get/any 'b [return false]
    ; there is only one #[unset!] value
    unless value? 'a [return true]
    ; errors can be disarmed and compared afterwards
    if error? :a [a: disarm :a b: disarm :b]
    ; we need to be transitive for decimals and money
    if any [decimal? :a money? :a] [
        return found? all [same? a b zero? a - b]
    ]
    ; we need to be transitive for dates

    if date? :a [return found? all [same? a b same? a/time b/time]]
    ; we need to be able to compare even the closed ports
    if port? :a [return equal? reduce [a] reduce [b]]
    ; our function has to work for structs
    if struct? :a [return same? third a third b]
    ; we can have something stronger than SAME? for bitsets
    if bitset? :a [
        unless same? a b [return false]
        if 0 = length? a [return true]
        unless equal? var: find a 0 find b 0 [return false]
        either var [
            remove/part a 0
            var2: find b 0
            insert a 0
        ] [
            insert a 0
            var2: find b 0
            remove/part a 0
        ]
        return var <> var2 
    ]
    same? :a :b
]
identical? a b ; == true
identical? a c ; == false

;; nexted-foreach a simple way of generating nexted foreach loops


compose-foreach: func [var data code][reduce ['foreach var data code]]

nexted-foreach: func [vars blocks code /local var][
	if empty? blocks [return code]

 compose-foreach first vars first blocks nexted-foreach next vars 
 next blocks code
]

eg; func [face /local var][print face/text] 
how do I get to the [print face/text ] part?

second func [face /local var] [print face/text] ; == [print face/text]

How do you clear out a local variable within a function? I have this 
scenario and I can't get the function to run more than once. I could 
copy the contents to a temp var but that seems silly.

a: func [ some-var /local s] [

	s: "example %text% string"
	replace/all s "%text%" some-var
]

Once I run this thing "s" never gets its orginal value.
Thanks

Pekr, I think it depends how many local vars are used in the function. 
With one local var, I got 14263 recursions before stack overflow. 
Maybe he can optimize by moving some variables out into a shared 
context.

It's the same method; all of the words (including the /local refinement) 
in the following function spec are local to the function's context:

	func [arg /local var]

In fact i use ALSO in functions to save the use of temporay variables.

Instead of doing  that:
func  [.. /local result][
	....
	result: ... 	;*** compute result
	... do something before returning the result
	:result    ;** return the result
]

I do:

func  [.. /local result][
	....
	 also (compute the result)
	.(do something before returning the result)
]

It saves the declaration of the result local var

Using ALSO returns some data. If your code look like this:

mp3-data: load-mp3-function


and that load-mp3-function ends with an ALSO, setting the local var 
to none, you still have a full copy in mp3-data. Actually you end 
up having 2 copies for some time, until the garbage collector frees 
the local version. Later in your code, you need to set mp3-data to 
none to free to memory (which the garbage collector does). Now, is 
this how you use ALSO and why you need it?

Where I see a potential problem with ALSO, is if you in a function 
load a local var with a huge amount of data, say 1GB. And then to 
release that data ends your function with:
also copy local-data local-data: none


At that moment between the two arguments to ALSO, you have 2 GB of 
data allocated. The first 1 GB is freed, when the garbage collector 
comes to it.

If the contents var is not unset and then the load-mp3 function is 
not anymre called.

Then, the garbage collector can't free the serie because it stays 
handled by the local var contents.

I know, i saw many implementations wich use recursive calls of parse 
(to deal with local var) in the past.
But i don't like that.

I saw it's slower most of the time than using recursive rules (well, 
it's the purpose of parse)

svv/vid-styles/button/multi/block: func [face blk][ ; <- This only 
does BUTTON for now.
	if pick blk 1 [
		;face/action: func [face value] pick blk 1

  face/action: func [face value /local window word] compose/only [

   window: face/parent-face ; Find the window face <-- (simplistic for 
   now)

   word: window/pane/1/var ; Find a word which references a field in 
   the window. <-- (simplistic for now)
			print "Remake action function."

   face/action: func [face value] probe append append copy [bind-funcs] 
   to-lit-word word (pick blk 1)
			do-face face value
		]

  if pick blk 2 [face/alt-action: func [face value] pick blk 2] ; <- 
  Also need to remake alt-action similarly to action, above.
	]
]
bind-funcs: func [word] [

 foreach window-function [hello][bind second get window-function word]
]

hello: does [f/text: copy "hello" show f]

open-window: does [
	view/new center-face layout ctx: vid-context [
		f: field
		button "Hello" [hello]
		button "Clear" [clear-face f]
	]
]

open-window
open-window
do-events

svv/vid-styles/button/multi/block: func [face blk][ ; <- This only 
does BUTTON for now.
	if pick blk 1 [
		;face/action: func [face value] pick blk 1

  face/action: func [face value /local window word] compose/only [

   window: face/parent-face ; Find the window face <-- (simplistic for 
   now)

   word: window/pane/1/var ; Find a word which references a field in 
   the window. <-- (simplistic for now)
			print "Remake action function."

   face/action: func [face value] probe append append copy [bind-funcs] 
   to-lit-word word (pick blk 1)
			do-face face value
		]

  if pick blk 2 [face/alt-action: func [face value] pick blk 2] ; <- 
  Also need to remake alt-action similarly to action, above.
	]
]
bind-funcs: func [word] [

 foreach window-function [hello][bind second get window-function word]
]

hello: does [f/text: copy "hello" show f]

open-window: has [window ctx] [
	window: view/new center-face layout vid-context/to [
		f: field
		button "Hello" [hello]
		button "Clear" [clear-face f]
		button "Clear window2's field" [clear-face window2/user-data/f]
	] 'ctx
	window/user-data: ctx
	window
]

window1: open-window
window2: open-window
do-events

yes but why I have 800 Ko used for a ingle function with a local 
var called twice

my-access: make ctx-access/panel [
    set-face*: func [face value /local val][
        if all [block? face/pane block? value][
            either set-word? value/1 [
                foreach [word val] value [
                    set-find-var face/pane to word! word val
                ]
            ] [
                foreach f face/pane [

                    if any [find f/flags 'input find f/flags 'panel] [
                        if not empty? value [
                            set-face f value/1
                            value: next value
                        ]
                    ]
                ]
            ]
        ]
    ]
]

Henrik, the hsv2rgb function, I made for Canvas RPaint. It takes 
H S V values as decimals in the area 0.0 - 1.0 as input:

hsv2rgb: func [
	H S V
	/local
		RGB
		var_h var_i
		var_1 var_2 var_3
		var_r var_g var_b
][
	RGB: 0.0.0
	either S = 0		;HSV values: 0 Ö 1
	[
		RGB/1: to-integer V * 255
		RGB/2: to-integer V * 255
		RGB/3: to-integer V * 255
	][
		var_h: H * 6
		if var_h >= 6 [var_h: 0]		;H must be < 1
		var_i: to-integer var_h
		var_1: V * (1 - S)
		var_2: V * (1 - (S * (var_h - var_i)))
		var_3: V * (1 - (S * (1 - (var_h - var_i))))
	
		switch var_i [
			0 [var_r: V			var_g: var_3	var_b: var_1]
			1 [var_r: var_2		var_g: V		var_b: var_1]
			2 [var_r: var_1		var_g: V		var_b: var_3]
			3 [var_r: var_1		var_g: var_2	var_b: V	]
			4 [var_r: var_3		var_g: var_1	var_b: V	]
			5 [var_r: V			var_g: var_1	var_b: var_2]
		]
	
		RGB/1: to-integer var_r * 255		;RGB results: 0 Ö 255
		RGB/2: to-integer var_g * 255
		RGB/3: to-integer var_b * 255
	]
	RGB
]

how to set local vars in parse ?

rule: [ "text" (var: "local") ]

var: "global"

f: func [ /local var ] [parse "test" rule  return var ]


f  ; result = none  not "local"

what to do get  result = "local"

;Does this help?
rule: [ "text" (var: "local") ]
var: "global"

f: func [ /local var ] [var: "local" parse "test" rule  return var 
]
f

f: has [ var rule ][
	var: none
	rule: [ "text" end (var: copy "local" ) ]
	parse/all [ "text" ] rule 
	var 	
]

;This also works
var: "global"
f: has [var] [
	rule: [ "test" (var: "local") ]
	parse "test" rule
	var
]
f

rule: [ "text" (var: "local") ]
var: "global"

f: func [ /local var ] [var: "funclocal" parse "text" rule  return 
var ]
f ;== "funclocal"
var ;== "local"

It is quite hard to decipher what actually Micha meant, I suppose, 
he wanted this?

rule: ["text" (var: "local")]

var: "global"

f: func [/local var] [parse "text" bind rule 'var return var]

size-text: xwindows is client/server. the x-server , that is your 
local computer, which offers to aplications to display things to 
you. And it has some important informations locally, especially the 
fonts (and can cache images and such).

/view needs access to the fonts and so access to a running x-server. 
the x-libs are only an interface to connect to the server. (The xserver-libs 
could be used directly, but well, /view does not do that. Seems to 
be tricky.)
A incomplete sketch how to do it, with no attention to security:

So with /view you need a running x-server, one way to do that  headless 
is vnc.  Can also run on another machine. 

Then you need to tell  rebol where it is, there is an env-var $DISPLAY. 
Which must be set before rebol runs. Did not figure out how to configure 
that. Running a bash-script as cgi, set  $DISPLAY, call the real 
rebol-script should work. And there may be issues with authentification, 
x-windows does not like everyone to connect by default, or the other 
way around, its too easy to make it too open ("xhost + ip"). There 
are more secure ways, but looked more complicated and i never tried. 
All in all i would run such things on windows.

REBOL [
Title: "ARCFOUR and CipherSaber"
Date: 17-Jan-2004
File: %arcfour.r
Author: "Cal Dixon"

Purpose: {Provides encryption and decryption using the ARCFOUR algorithm}

Note: {this implementation can decrypt data at about 40KB/s on my 
1Ghz AMD Duron system with Rebol/View 1.2.10.3.1}
Library: [
level: 'advanced
platform: 'all
type: [function module protocol]
domain: [encryption scheme]
tested-under: [view 1.2.10.3.1 on [W2K] by "Cal"]
license: 'PD
support: none
]
]


;ARCFOUR specification: http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt

;CipherSabre specification: http://ciphersaber.gurus.com/faq.html#getrc4


arcfour-short: func [key [string! binary!] stream [binary! string!] 
/mix n /local state i j output swap addmod sz][

swap: func [a b s /local][ local: sz s a poke s a + 1 to-char sz 
s b poke s b + 1 to-char local ]
addmod: func [ a b ][ a + b // 256 ]
sz: func [ s a ][ pick s a + 1 ]

state: make binary! 256 repeat var 256 [ insert tail state to-char 
var - 1 ]

j: 0 loop any [ n 1 ] [ i: 0 loop 256 [ swap i j: addmod j add sz 
state i sz key i // length? key state i: i + 1] ]
i: j: 0 output: make binary! length? stream
repeat byte stream [
swap i: addmod i 1 j: addmod j sz state i state

insert tail output to-char xor~ byte to-char sz state addmod (sz 
state i) (sz state j)
]
clear state
return output
] 

make root-protocol [
addmod: addmod: func [ a b ][ a + b // 256 ]
sz: func [ s a ][ pick s a + 1 ]

swap: func [a b s /local][ local: sz s a poke s a + 1 to-char sz 
s b poke s b + 1 to-char local ]
ins: get in system/words 'insert
i: 0 j: 0
open: func [port][
port/state/tail: 2000
port/state/index: 0
port/state/flags: port/state/flags or port-flags

port/locals: context [ inbuffer: make binary! 40000 state: make binary! 
256]
use [key n i j] [
key: port/key
n: port/strength
repeat var 256 [ ins tail port/locals/state to-char var - 1 ]
j: 0 loop any [ n 1 ] [
i: 0 loop 256 [

swap i j: addmod j add sz port/locals/state i sz key i // length? 
key port/locals/state i: i + 1
]
]
]
i: j: 0
]
insert: func [port data][
system/words/insert tail port/locals/inbuffer data do []
]
copy: func [port /local output][
output: make binary! local: length? port/locals/inbuffer
loop local [

swap i: addmod i 1 j: addmod j sz port/locals/state i port/locals/state

ins tail output to-char sz port/locals/state addmod (sz port/locals/state 
i) (sz port/locals/state j)
]
local: xor~ output port/locals/inbuffer
clear port/locals/inbuffer
local
]

close: func [port][ clear port/locals/inbuffer clear port/locals/state 
clear port/url clear port/key]
port-flags: system/standard/port-flags/pass-thru
net-utils/net-install arcfour self 0
]

arcfour: func [key stream /mix n /local port][
port: open compose [scheme: 'arcfour key: (key) strength: (n)]
insert port stream
local: copy port
close port
return local
]


; CipherSaber is an ARCFOUR stream prepended with 10 bytes of random 
key data
ciphersaber: func [ key stream /v2 n ][

arcfour/mix join key copy/part stream 10 skip stream 10 either v2 
[ any [ n 42 ] ][ 1 ]
]

G4C TUT_MCListview

// ===========================================================
// A Multi Column (or Database) Listview..
// ===========================================================

WINDOW 126 90 367 373 "Listview"
	winattr style resize

xOnLoad
	// add some records to the listview & open..
	gosub #this AddRecords
	guiopen #this

xOnClose
	guiquit #this

// ===========================================================
// The listview
// - This is a normal MULTISELECT listview (the default).
// For this type to be triggered, you must double-click it.
// ===========================================================

XLISTVIEW 0 0 0 0 'The Title' "" var

	attr ID mylv
	attr resize 0022
	attr frame sunk

	// Give it a grid and allow the user to drag, drop & re-arrange
	// the lines - You can add more styles here..
	attr style grid/arrange/drag/drop/arrange

	// Add some columns. The first one we state with a '#'
	// in front to indicate we mean the 1st column.
	attr LVCOLUMN '#Item/width/120/TITLE/Description'

 attr LVCOLUMN 'Units/width/60/TITLE/Units/TYPE/number/JUSTIFY/RIGHT'

 attr LVCOLUMN 'Amount/width/60/TITLE/Amount/TYPE/number/JUSTIFY/RIGHT'

 attr LVCOLUMN 'Total/width/60/TITLE/Total/TYPE/number/JUSTIFY/RIGHT'

	// show the line double clicked..

 SetWinTitle #this 'SUM: $%Units x $%Amount = $($%Units * $%Amount)'


// ===========================================================
// This is a routine to add 100 records with various
// meaningless values to the above listview. Note how
// the fields can be used as normal variables.
// ===========================================================

xRoutine AddRecords
	local c

	use lv #this mylv

	// before we start, we HIDE the listview. This will
	// stop Gui4Cli from visually refreshing it every time
	// we add a record and will GREATLY increase the speed.
	// This will have no effect if the window is closed.
	// After we finish, we show it again..
	setevent #this mylv HIDE

	for c 0 100
		// add an empty record..
		lv add ''

		// Fill the fields with various values..
		%Item   = "This is Item $c"
		%Units  = $($c * 3)
		%Amount = $(($%Units / 2)*1000)
		%Total  = $($%Units * $%Amount)

	endfor

	// Show the listview again, refreshing the display..
	setevent #this mylv SHOW

// ===========================================================
// Right mouse button handling - Some menu choices..
// ===========================================================

xOnRMB


 QuickMenu -1 -1 'Select All/Remove selected/Add 100 records/#sepa/cancel'
	use lv #this mylv
	docase $$choice
		case = 0			// Select All
			lv select all
			break
		case = 1			// Remove selected
			lv delete selected
			break
		case = 2			// Add some records..
			gosub #this AddRecords
	endcase

How's this for focus / unfocus trigger logic?

1. Add two user-definable action handlers to ctx-rebgui

	app-focus-action: func [face] [true]
	app-unfocus-action: func [face] [true]

2.Modify the ctx-rebgui/edit focus and unfocus functions:

	unfocus: has [face][
		if face: view*/focal-face [
			unless face/unfocus-action face [return false]
		] 
	...

	focus: func [
		"Focuses key events on a specific face."
		face [object!]
	][
		unless unfocus [return]
		if face/show? [
			unless face/focus-action face [return false]
	...

3. Extend the standard rebface definition

4. Add the following to the layout function:


 focus-action: either attribute-focus-action [make function! [face 
 /local var] attribute-focus-action] [:app-focus-action]

 unfocus-action: either attribute-unfocus-action [make function! [face 
 /local var] attribute-unfocus-action] [:app-unfocus-action]

which would then let us write code like:


 ctx-rebgui/app-focus-action: func [face] [face/text: form random 
 1000]

	display "" [
		field
		field focus [face/text: form now/time/precise]
		field
	]


The logic is simple: "Execute the default focus / unfocus functions 
(which in turn default to true) *unless* a focus / unfocus function 
has been provided for the face. When a focus / unfocus event is called 
execute the assigned handler function *first* and only proceed if 
it returns true."

Does this meet the design requirement?

; default one is very stupid
my-access: make ctx-access/panel [
    set-face*: func [face value /local val][
        if all [block? face/pane block? value][
            either set-word? value/1 [
                foreach [word val] value [
                    set-find-var face/pane to word! word val
                ]
            ] [
                foreach f face/pane [

                    if any [find f/flags 'input find f/flags 'panel] [
                        if not empty? value [
                            set-face f value/1
                            value: next value
                        ]
                    ]
                ]
            ]
        ]
    ]
]

map: func [
    [throw]

    "Evaluates a block for each value(s) in a series and returns them 
    as a block."

    'word [word! block!] "Word or block of words to set each time (local)"
    data [block!] "The series to traverse"
    body [block!] "Block to evaluate each time"
    /into "Collect into a given series, rather than a new block"
    output [series!] "The series to output to"
] [

    unless into [output: make block! either word? word [length? data] 
    [divide length? data length? word]]

    head foreach :word data compose [output: (:insert)  output (to paren! 
    body)]
]
>> map x [1 2 3 4][x + x]
== [2 4 6 8]
>> map [x y][1 2 3 4][x + y]
== [3 7]
>> map/into [x y][1 2 3 4][x + y][10 11 12]
== [3 7 10 11 12]

But still a problem with the output var collision

Well finding an example is simple: Just convert to stack code and 
figure out when the stack would be used more than one deep between 
ops. That means more than one temp var. What we get for going to 
a register machine in a stack language :)


This would all be solved by a built-in USE directive with literal 
blocks that acts like USE in REBOL except only binding at rebcode 
creation time. It could be implemented as a built-in rewrite rule, 
changing the temporary variables to local variables, renaming if 
necessary. This rewrite would be done after the user-defined rewrites 
were done, but before the binding to the opcodes.


Let me think about how this could be implemented - I am late for 
a class.

inside the function you do bind/copy blk 'local-var

local-var is defined but the other ones, tag-title, tag-x, tag-y 
... I don't want to have to define in /local local-var ...

This is a dirty hack of the LAYOUT function: you're warned if a set-word 
in the layout is not local.

use [x src][
	src: third find second :layout 'while
	src: first find src/forever block!

 insert back tail insert src [if same? in system/words x:][x [print 
 ["Warning:" x "is global var"]]]
]

impressed! 8) I finally gave another try at php support in cheyenne 
and after patching fastcgi.c as suggested it now works like a charm.

If you are on os x and use macports, here is a way to patch and compile:

sudo port install php5 +mysql5 +fastcgi
sudo port uninstall php5
cd /opt/local/var/macports/distfiles/php5/
sudo tar -xjf php-5.2.6.tar.bz2
>> run patch below
tar -cjf php-5.2.6.tar.bz2 php-5.2.6
sudo port install php5 +mysql5 +fastcgi checksum.skip=yes

copy of Dockimbel's patch with path fixed for this example

;---- cut'n paste the following code in REBOL's console ----

patch-php: has [buffer pos][ target: %php-5.2.6/sapi/cgi/fastcgi.c 
if none? attempt [buffer: read target][ print "unable to find the 
file to patch!!" exit ] either parse buffer [ thru "int fcgi_accept_request(" 
to "if (req->fd >= 0) {" pos: to end ][ insert pos "^/^-^-^-^-break;^/^-^-^-^-" 
write target buffer print "patch applied." ][ print "failed to locate 
the line to patch!!" ] ]
patch-php ;---- end of code ----

This is both against the structure of Unix and modern Windows systems.


UNIX filesystem layout usage are not identical. Here are the Apache 
error log location in just 3 UNIX flavours (among dozens):

* RHEL / Red Hat / CentOS / Fedora Linux Apache error file location 
- /var/log/httpd/error_log

* Debian / Ubuntu Linux Apache error log file location - /var/log/apache2/error.log

* FreeBSD Apache error log file location - /var/log/httpd-error.log

and here are the possible locations of configuration file:
* /usr/local/etc/apache22/httpd.conf
* /etc/apache2/apache2.conf
* /etc/httpd/conf/httpd.conf


Notice how the file name changes too (both for the log and conf files). 
BTW, I personnally prefer the GoboLinux approach ;-).


One the Windows front, it is barely better. The registry database 
is fine for storing parameters (name/value couples), but not a REBOL 
dialect file. A common way is to store files created at runtime in 
%USER%/AppData/Local/<appname>/. Cheyenne stores all his files (including 
config file) either in the local folder or in %ALL_USERS%/Cheyenne/. 
Storing them in %USER% hierarchy should be better.


Taking into account every OS specificities (or oddities) is not always 
a good choice for a cross-platform product. I know that Cheyenne 
needs to be gentle with the OS best practices, so I am willing to 
improve it whenever it is possible, but without sacrificing the default 
behaviour (because that is the way I want it to work for me).


BTW, I am also willing to test the centralized logging approach, 
but it has to be a cross-platform solution. So an abstraction layer 
needs to be built with connectors for UNIX syslog daemon and Windows 
Event Logger (they are two types to support: pre-Vista system and 
new Vista/7 one). Has anyone already worked on such wrappers with 
REBOL?


I personnaly need that the log files be exactly in the same format 
and if possible at the same place across platforms to make my life 
easier, so this will keep being the default anyway. The current -f 
internal Cheyenne command line (Windows specific currently) could 
be extended to work on UNIX too (and no Max, this one cannot go into 
the config file, because it indicates where the config file is located 
;-)).

only set-word are used as markers to declare a var as local

I found an bad effect of not binding words in blocks at all, before 
the block is evaluated. Functions like LOOP take 2 args, count and 
block. By not binding the block content before it's evaluated, the 
count arg local to LOOP is found, if a count var is used in the block.

So I guess the REBOL early bind of words is better.

Maybe a function, where the local var is set, if some condition is 
fulfilled, and then the local is returned in the end, being NONE, 
if it wan't set. Is that an example of such a problem function?

OK, this is freaky:

>> system/version
== 2.7.8.2.5
>> a: list-env
== [
    "TERM_PROGRAM" "Apple_Terminal" 
    "TERM" "xterm-color" 
    "SHELL" "/bin/bash" 
    "TMPDIR" "/var/folders/6O/6OnXy9XG...
>> help a
A is a block of value: [
    "TERM_PROGRAM" "Apple_Terminal" 
    "TERM" "xterm-color" 
    "SHELL" "/bin/bash" 

    "TMPDIR" "/var/folders/6O/6OnXy9XGEjiDp3wDqfCJo++++TI/-Tmp-/" 
    "Apple_PubSub_Socket_Render" "/tmp/launch-BrITkG/Render" 
    "TERM_PROGRAM_VERSION" "273.1" 
    "USER" "Ash" 
    "COMMAND_MODE" "legacy" 
    "SSH_AUTH_SOCK" "/tmp/launch-HlnoPI/Listeners" 
    "__CF_USER_TEXT_ENCODING" "0x1F5:0:0" 

    "PATH" {/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin} 
    "PWD" "/Users/Ash" 
    "LANG" "en_AU.UTF-8" 
    "SHLVL" "1" 
    "HOME" "/Users/Ash" 
    "LOGNAME" "Ash" 
    "DISPLAY" "/tmp/launch-U0Gaqw/org.x:0" 
    "_" "/Users/Ash/REBOL/rebol"
]
>> length? a    
== 18
>> select a "USER"
== "Ash"
>> select a "HOME"
== none

It's for the parse function, I'm working on, and I want to be sure, 
I don't get a local var, if vars are used in the parse rules.

I think this is the correct behaviour, more compatible with REBOL 
as well.

I'm not sure about giving a warning if a local var. clashes with 
a global one (just for enums may be?)