Xotcl July 2009

xotcl@alice.wu.ac.at

4 participants
5 discussions

Re: [Xotcl] xotcl crash
by Stefan Sobernig 25 Jul '09

25 Jul '09

> Message: 1 > Date: Fri, 24 Jul 2009 10:21:04 +0200 > From: Gustaf Neumann <neumann(a)wu.ac.at> > Subject: Re: [Xotcl] xotcl crash > To: Tibichte <zak(a)isa-software.com> > Cc: xotcl(a)alice.wu-wien.ac.at > Message-ID: <4A696EF0.7010906(a)wu.ac.at> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > > 2- This forwarding method causes xotcl to crash: > > > > obj forward f2 list {%@end 13} %self %1 > > > > ? { obj f2 1 2 3 } > > There is a bug in the current xotcl versions when both > %@end and %1 is used, which will be fixed in the next release. > The %1 means that the first argument from the provided > argument list (here "1") will be placed at the given > position. The argument is consumed and the remaining > arguments (here "2" and "3") are appended to the arguments > from the forward definition. S The fact that %1 consumes = mutates the caller arg list and the %@POS substitution operates on the mutated state of the resulting (=final) list (kind of) made me think. And ... I guess I found the culprit of this crashy interaction (see the patch attached): once %1 consumes the first element of the caller arg list, the currently arg handling mechanism for forwards counts %1 as an extra arg in the overall arg list erroneously. however, it is rather a placeholder for an already counted arg (=the first in the caller arg list). This +1 overestimation in the internal assembly of the final arg list led to a memory access violation for the %@POS substitution under end offsets (end, end-1, end-2; in the Tcl sense of the word) because end offsets require a correct total args count internally (which used to report +1). as for the patch: it is a minor and fairly non-invasive change. all regression tests pass, i added some extra cases to test for the %1 + %@POS-under-end-offsets interaction. the patch can be applied to the a xotcl-1.6.3 source snapshot. cheers //stefan

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xotcl crash
by Tibichte 24 Jul '09

24 Jul '09

Hello, I am experimenting with the xotcl method forwarding. 1- if I create a method forwarding f1: obj forward f1 list {%@end 13} %self ? { obj f1 1 2 3 } [list ::obj 1 2 3 13] Question: Why ::obj was inserted at the beginning but not at the end? 2- This forwarding method causes xotcl to crash: obj forward f2 list {%@end 13} %self %1 ? { obj f2 1 2 3 } Regards, Abderrazak Tibichte

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Re: [Xotcl] two procs (-proc) for Attribute
by Mykhaylo Sorochan 20 Jul '09

20 Jul '09

Stefan, I was interested in case a). I was a little wrong with the syntax and was not able to build the statement right. Thanks. > # ad a) > # > Class create C -slots { > Attribute create a1 -proc assign args { > puts "[self]->[self proc] called" > next > } -proc get args { > puts "[self]->[self proc] called" > next > } > } > > C create c > c a1 1 > c a1 >

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Re: [Xotcl] two procs (-proc) for Attribute
by Stefan Sobernig 20 Jul '09

20 Jul '09

Mykhaylo, > How to define several procs for one Attribute in class definition? > Particularly, I want to define both assign and get procs at once. i am not entirely confident that i grasbed the meanings of "serveral procs for one Attribute" and "at once". Do you mean: a) define 2 or more (per-object methods, i.e., procs) per slot object "at once"? b) define 2 (per-instance methods, i.e., instprocs) per family of slot objects "at once"? anyways, maybe some of the following is helpful to you: # # ad a) # Class create C -slots { Attribute create a1 -proc assign args { puts "[self]->[self proc] called" next } -proc get args { puts "[self]->[self proc] called" next } } C create c c a1 1 c a1 # # ad b) # Class MyAttribute -superclass Attribute \ -instproc assign args { puts "[self]->[self proc] called" next } -instproc get args { puts "[self]->[self proc] called" next } Class create D -slots { MyAttribute create a1 Attribute create a2 } D create d d a1 1 d a1

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two procs (-proc) for Attribute
by Mykhaylo Sorochan 19 Jul '09

19 Jul '09

Hello, How to define several procs for one Attribute in class definition? Particularly, I want to define both assign and get procs at once. -- Regards, Mykhaylo Sorochan

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Xotcl July 2009