'''3. Call graph analyzer'''

Write a procedure, ''callgraph'', that accepts a string parameter containing a Tcl procedure call, and evaluates that parameter in the caller's scope. Upon return from the evaluation, the procedure should display in some useful form the call graph: an indication of what Tcl commands were invoked by what other Tcl commands in the course of running the procedure.
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[Tcl2002 programming contest: solutions to problem 3]
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[The Great Canadian Tcl/Tk Programming Contest], eh?