From bug-octave-request at bevo dot che dot wisc dot edu Fri Dec 13 10:07:29 2002
Subject: Variables not being cleared
From: Andrew Jackson <andrew dot jackson at jesus dot ox dot ac dot uk>
To: bug-octave at bevo dot che dot wisc dot edu
Date: Fri, 13 Dec 2002 16:06:56 +0000

I'm not certain this is a bug, but it is certainly different behaviour
between 2.1.36 and 2.1.40.

I have two script files, one calling the other. The first sets up variables
that I don't want to have to enter every time I call the second script. The
second does an exist() on the variables to see if I need to enter them.

The problem arises that having run the scripts once despite calling clear
and checking the existance of the variables manually with who and exist
(they have gone) when I rerun the script the variables, which are all
defined as globals magically reappear with their previous values.

Clear in 2.1.36 works and the variable *really* are cleared, whereas in
2.1.40 they only appear to have been cleared.

An example:
---Script A---
global A B C
A = 1;
B = 2;
scriptb
---End Script---

---Script B---
global A B C
if (!exist('A'))
	A = input('A: ');
endif
if (!exist('B'))
	B = input('B: ');
endif
if (!exist('C'))
	C = input('C: ');
endif
A
B
C
---End Script---

The octave session :

octave:1> scripta
C: 12
A = 1
B = 2
C = 12
octave:2> clear
octave:3> who -variables
octave:4> exist('A')
ans = 0
octave:5> exist('B')
ans = 0
octave:6> exist('C')
ans = 0
octave:7> scripta
A = 1
B = 2
C = 12
octave:8> 

Whereas 2.1.36 asks for C on the second run.

Andrew
-- 
Andrew J Jackson                
RKT Group
Physical & Theoretical Chemistry Laboratory
Oxford University



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