TclProp: A Data-Propagation Formula Manager for Tcl and Tk
Sunanda Iyengar
Joseph A. Konstan
Department of Computer Science
University of Minnesota
Minneapolis, MN 55455
Abstract
TclProp is a data propagation formula manager for Tcl and Tk. It
supports and enforces one-way declarative relationships among
variables. If, for example, we enter the formula A = B + C, whenever B
or C changes, A is also updated to reflect the new sum. TclProp also
supports triggers -- code to be executed when one of a set of
variables changes. And, TclProp includes a mechanism for linking
variables to object attributes (e.g., the enabled/disabled status of a
button) so these attributes can be used in formulas and triggers. This
paper presents an example of how data propagation formulas can
simplify programming and presents the design and implementation of
TclProp 1.0, an implementation built in Tcl.
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