Well, the terms that you are referring to are
standard object oriented programming terms. There are some
sites that can offer a relative introduction to what
you are asking, but in order to understand in depth
these issues, you should read a good object-oriented
programming book, or an OTcl manual in specific.

However, you can check the following link:


It has an introduction to OTcl, in somehow more concrete terms.

In order to give you a relatively short description of the terms that you
in your question...:

"self" is used when we need to refer to the SAME object that is invoking the
Is usually invoked from whithin a method (i.e. a procedure inside a class
definition) and it
refers (i.e. substitutes) the name of any object that will use this keyword
when it will invoke
the method that contains it.

"global" is used to refer to the variables that are in global scope. It is
usually invoked
from within procedures and/or class methods that want to include in their
local variable
scope some variables from the global scope (i.e. variables that are declared
outside any
procedures and methods. Variables that are declared in the "main" body of a
tcl script).

"instproc" and "instvar" refer to the way that we can declare new class
methods (instproc,
is derived from instance procedure), which will be used by the corresponding
and instvar (instance-variable) refers to the way we declare class
attributes, or in other words, variables that will contain attributes (like
integers, strings,
arrays, other objects, etc) for every object-instance that belongs to the
same class (or any other inherited class).

However, as you can see all these are referring to standard object-oriented
and if you do not have such a background I would suggest (starting from the
link above)
to read one or two "short-course" manuals, just to get the hang of it.

Hope that I have helped you.

Kind Regards,


> ---------- Forwarded message ----------
> From: "balraj karthikeyan" <[EMAIL PROTECTED]>
> To: ns-users@ISI.EDU
> Date: Tue, 16 May 2006 12:36:21 +0930
> Subject: [ns] query:otcl command explanation?
> hi
> I am trying to understand the meaning of commands we use in otcl
> programming like;
> what is self?
> what is global?
> why we use instproc,instvar and ....
> someone plz help me by giving a good link other then otcl tutorial and
> manual....
> Cheers,
> Cartic

Filippos N Kolovos

Software Systems Analyst & Engineer
M.Sc. (Eng.) in Data Communications

Automation & Networking Department
University of Macedonia Library
Egnatia 156, P.O.Box 1591
540 06 Thessaloniki, Greece

           [EMAIL PROTECTED]

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