Evaluating Message Passing Control Techniques in Smalltalk

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Smalltalk. Esug Tutorial, 1994. [IKM. ·. 97] D. Ingalls, T. Kaehler, J. Maloney, S. Wallace, and. A. Kay. Back to the Future: The Story of Squeak, …

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Evaluating Message Passing Control Techniques in Smalltalk
St’ephane Ducasse
Software Composition Group, Universit¨at Bern
ducasse@iam.unibe.ch
http://www.iam.unibe.ch/ducasse/
Appeared in JOOP (Journal of Object-Oriented Programming) June 1999
Abstract
In a language like Smalltalk in which objects communicate
only via message passing, message passing
control is a fundamental tool for the analysis
of object behavior (trace, spying) or for the definition
of new semantics (asynchronous messages,
proxy,…). Different techniques exist, from the well
known approach based on the specialization of the
doesNotUnderstand: method to the exploitation
the method lookup algorithm done by the virtual
machine. Until now no comparison between these
techniques has been made. In this article we compare
the different techniques taking into account the
reflective aspects used, the scope, the limit and the
cost of the control.
Keywords: message passing control, instance specialization,
doesNotUnderstand:, error handling,
method compilation, anonymous class, minimal object
1 Message Passing Control: A
need
Message passing control is the corner stone of a
broad range of applications from application analysis
(trace[BH90, PWG93], interaction diagrams,
class affinity graphs) to the introduction of new language
features (multiple inheritance[…