This problem may be related to Dr Wes Munsil's problem on "invalid command
name". Here is the problem script:
set x [java::new String foo]
after 1000 "$x toString"
unset x
update
You will get an error "invalid command name". Comparing that to the script
below:
set x [java::new String foo]
after 1000 [list eval $x toString]
unset x
update
Your will not get an error. The problem seems to be that Tcl believes that
a string representation of an object can always be converted back into the
original object. This is not true in the case of the Java object. The
first script uses the string form of the Java object to reference the
object. But that does not increment the ref count of the real object. As a
result, the later 'unset' call removed the real Java object. Why can't you
not use "unset x"? Well if this script is inside a proc, then x might be a
local variable, which will be removed after the proc returns.
The same script rewritten using an explicit list does use the real Java
object rather than its string form. As a result, the 2nd script works.
I am encountering this problem right now in a different form. I am
constructing an asynchronous callback function inside Java using a TclList
object, {command_name java_obj_1 java_obj_2}. The list contains some Java
objects, which are the arguments to the callback function. However, when
the callback function is invoked, the function is getting the string
representation of the argument rather than the real Java objects. This is
not good because you can't easily find your Java object given a string
representation.
I wonder if similar problem happens in the C world. But a C object can
always use a pointer address as its string representation. Then, given the
string representation, a valid C object can be found.
-- Jiang Wu
[EMAIL PROTECTED]
----------------------------------------------------------------
The TclJava mailing list is sponsored by Scriptics Corporation.
To subscribe: send mail to [EMAIL PROTECTED]
with the word SUBSCRIBE as the subject.
To unsubscribe: send mail to [EMAIL PROTECTED]
with the word UNSUBSCRIBE as the subject.
To send to the list, send email to '[EMAIL PROTECTED]'.
An archive is available at http://www.mail-archive.com/tcljava@scriptics.com
