Contexts and global variables

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cameyo
Posts: 183
Joined: Sun Mar 27, 2011 3:07 pm
Location: Italy
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Contexts and global variables

Post by cameyo »

I have the following problem:

Code: Select all

; create two contexts (A1, A2)
> (context 'A1)
;-> A1
A1> (context MAIN)
;-> MAIN
> (context 'A2)
;-> A2
A2> (context MAIN)
;-> MAIN
; create a variable "a"
> (setq a 2)
;-> 2
> (context 'A1)
;-> A1
; context A1 do not see the variable "a"
A1> a
;-> nil
; context A1 do not see the variable "a"
A1> (context 'A2)
;-> A2
A2> a
;-> nil
A2> (context MAIN)
;-> MAIN
> a
;-> 2

; set variabile "a" to global
(global 'a)

; but A1 and A2 do not see the variable "a"
> (context 'A1)
;-> A1
A1> a
;-> nil
A1> (context 'A2)
;-> A2
A2> a
;-> nil

But this works (do not check variable value on contexts before globalize it:

A2> (context MAIN)
;-> MAIN
> (context 'B2)
;-> B2
B2> (context MAIN)
;-> MAIN
> (context 'B1)
;-> B1
B1> (context MAIN)
;-> MAIN
> (setq b 3)
;-> 3
> (global 'b)
;-> b
> (context B1)
;-> B1
B1> b
;-> 3
B1> a
;-> 2
B1> (context B2)
;-> B2
B2> b
;-> 3
B2> a
;-> 2
B2>

B2> (context MAIN)
MAIN
; the context A1 see only "b" ("a" is nil)
> (context A1)
A1
A1> a
nil
A1> b
3
A1>

; change variable value
A1> (context MAIN)
MAIN
> (setq a 10)
10
> a
10
> (context B1)
B1
B1> a
10
B1> (context A1)
A1
A1> a
nil
A1>
Why A1 and A2 do not see the variable "a" ?
what am i doing wrong?
Is there a rule to define global variables and contexts?

Lutz
Posts: 5289
Joined: Thu Sep 26, 2002 4:45 pm
Location: Pasadena, California
Contact:

Re: Contexts and global variables

Post by Lutz »


cameyo
Posts: 183
Joined: Sun Mar 27, 2011 3:07 pm
Location: Italy
Contact:

Re: Contexts and global variables

Post by cameyo »

Thanks Lutz.

Code: Select all

> (setq a 1)
;-> 1
> (context 'A1)
;-> A1
A1> (symbols)
;-> ()
A1> a
;-> nil
A1> (symbols)
;-> (a)

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