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TraceDialog

TraceDialog[expr]
initiates a dialog for every expression used in the evaluation of expr.

TraceDialog[expr, form]
initiates a dialog only for expressions which match form.

TraceDialog[expr, s]
initiates dialogs only for expressions whose evaluations use transformation rules associated with the symbol s.

MORE INFORMATION

The expression to be evaluated when a dialog is called is given as Out[$Line] of the dialog, wrapped in HoldForm. The expression can be seen by asking for % when the dialog is first started.

Any value returned from the dialog is discarded.

TraceDialog[expr] returns the result of evaluating expr.

Basic Examples (1)

Trace evaluation of an expression, entering a Dialog whenever addition is encountered:

In the dialog you can look at the evaluation stack:

(Dialog) Out[2]=

This returns from the first dialog:

Another dialog has started:

(Dialog) Out[4]=

In the dialog, you can check evaluations to see if they come out as you expect:

(Dialog) Out[5]=

(Dialog) Out[6]=

Return from the second dialog. Since there are no more additions, the evaluation will finish:

Dialog Return Trace TraceScan

Tracing Evaluation

Symbolic Execution History

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