[Xotcl] Calling object

[Stefan Sobernig]

Kristoffer,

> [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.

@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 
example).

> 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 :)

//stefan

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