Thank you. Very good information and well
explain. My hat's off to you!
Tim
At 03:52 PM 4/4/00 -0700, you wrote:
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
>Sent: Tuesday, April 04, 2000 10:05 AM
>To: [EMAIL PROTECTED]
>Subject: [REBOL] [REBOL]Advice in using global values Re:
>
>> As Rebol reads through a script, when it encounters begin-block symbol (
>"[" ) it sets aside a special place (?) for any variables that are
>subsequently defined. When Rebol encounters the corresponding end-block
>symbol ( "]" ) all the variables in that special place are freed(?). So, to
>keep the number of variables low, you want to insure that variables are
>defined as late as possible, and freed as early as possible. The way to do
>this is to divide your script into blocks ( "func" blocks ), and do not
>introduce variables until you reach the block you need them.
>
>It kinda works this way for locally defined words of a function, but not for
>blocks in general.
>
>For REBOL it's better though of as: any local definition of a word "masks"
>the previous definition. The word isn't really "freed up" when the local
>definition falls out of context. The word is still defined in system/words.
>The very first time a word is referred to, it is immediately defined in
>system/words with a value of unset!. If you assign a value (to a "new" word)
>in a global context, this unset! is changed to the value. If you assign a
>value (to a "new" word) in a local context - masking the previous value of
>unset! - then fall out of that context, the value of the word reverts to
>unset!.
>
>If you work long enough in the same REBOL session - not just doing the same
>thing over and over - you'll fill up system/words even though most of them
>were defined as local variables which are out of context (and/or set to
>unset!).
>
>- Michael Jelinek
>
>
