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.
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.
Details and Options
- 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.
Examples
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:
This returns from the first dialog:
Another dialog has started:
In the dialog, you can check evaluations to see if they come out as you expect:
Return from the second dialog. Since there are no more additions, the evaluation will finish:
Tech Notes
Related Guides
History
Introduced in 1991 (2.0)
Text
Wolfram Research (1991), TraceDialog, Wolfram Language function, https://reference.wolfram.com/language/ref/TraceDialog.html.
CMS
Wolfram Language. 1991. "TraceDialog." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/TraceDialog.html.
APA
Wolfram Language. (1991). TraceDialog. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/TraceDialog.html
BibTeX
@misc{reference.wolfram_2025_tracedialog, author="Wolfram Research", title="{TraceDialog}", year="1991", howpublished="\url{https://reference.wolfram.com/language/ref/TraceDialog.html}", note=[Accessed: 05-December-2025]}
BibLaTeX
@online{reference.wolfram_2025_tracedialog, organization={Wolfram Research}, title={TraceDialog}, year={1991}, url={https://reference.wolfram.com/language/ref/TraceDialog.html}, note=[Accessed: 05-December-2025]}