is an option for functions such as PersistentSymbol and InitializationValue that specifies a function to apply to a new value that is being assigned.
ValuePreprocessingFunction
is an option for functions such as PersistentSymbol and InitializationValue that specifies a function to apply to a new value that is being assigned.
Details
- When a value is to be assigned with PersistentSymbol ["name",…]=value or InitializationValue ["name",…]=value, the setting of the ValuePreprocessingFunction option is applied to value; the result is then assigned. If the result is $Failed , no assignment is done.
- The default setting is ValuePreprocessingFunction->Identity , which does not modify the value to be assigned.
- Settings for ValuePreprocessingFunction are typically done for the "Installation" persistence location.
Examples
Basic Examples (1)
Define a value preprocessing function that accepts only integers:
Set up a default value and the value preprocessing function for a persistent value named "int":
Assign an integer at any persistence location:
Assigning anything else generates an error, and the assignment is not performed:
See Also
History
Text
Wolfram Research (2017), ValuePreprocessingFunction, Wolfram Language function, https://reference.wolfram.com/language/ref/ValuePreprocessingFunction.html.
CMS
Wolfram Language. 2017. "ValuePreprocessingFunction." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ValuePreprocessingFunction.html.
APA
Wolfram Language. (2017). ValuePreprocessingFunction. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ValuePreprocessingFunction.html
BibTeX
@misc{reference.wolfram_2025_valuepreprocessingfunction, author="Wolfram Research", title="{ValuePreprocessingFunction}", year="2017", howpublished="\url{https://reference.wolfram.com/language/ref/ValuePreprocessingFunction.html}", note=[Accessed: 08-January-2026]}
BibLaTeX
@online{reference.wolfram_2025_valuepreprocessingfunction, organization={Wolfram Research}, title={ValuePreprocessingFunction}, year={2017}, url={https://reference.wolfram.com/language/ref/ValuePreprocessingFunction.html}, note=[Accessed: 08-January-2026]}