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Re: [Xotcl] Calling object

From: Stefan Sobernig <>
Date: Fri, 09 Jul 2010 18:21:14 +0200


> [uplevel] doesn't help here as [self callingobject] will always return the same, whatever stack level I call it from (is this a bug or intentional?). Basically there is no way to check "caller of caller".

indeed, i checked the code behind [self callingobject] (and its like,
e.g. [self callinglevel]) and it appears to me that this family is not
[uplevel]-aware. If you compare with [self proc], you will find that
this actually is (also in your example). I spotted the code which
unwinds the hybrid xotcl/tcl callstack under [uplevel]. the patch below
attached to the email fixes the behaviour and [make test] runs, but i
might easily miss sth. out here.

_at_gustaf neumann: could you please check the patch? i also have the
feeling that some refactoring can be done in
XOTclCallStackFindLastInvocation(). the patch is against the git master
branch (1.6.6).

in the new and rewritten callstack management and introspection for the
upcoming major release, this has been solved (i checked it with your

> Basically there is no way to check "caller of caller".

well, you already guessed in the right direction: provide a filter and
manage reentrant/self-directed messages accordingly. so you could keep
track of the initial caller of the caller (which is not self).

i am also not quite sure whether "the caller of the caller" makes sense
in an "invocation access control" scenario, as the caller-caller was
already allowed access to the object (i.e., by calling do()). so a
friendclass-like approach would not need that, for instance. while a
eiffel-kind of feature export would certainly do. but anyway, in xotcl,
nothing is written in stone anyways :)