# Expressions SPAD.neXt contains a powerful expression evaluation system, which can be used throughout all events and actions. If not stated differently in the event/action the result of the expression is expected to be a number. By default all data references will be interpreted as numbers. You might need to apply conversion (see [Functions](/features/expressions/functions.md)) or preface your expression with `''+` (two single quotes) to enforce the expression system to interpret (and automatically convert) everything as a string. The underlying expression system (ncalc) is Open-Source and can be found [here](https://github.com/ncalc/ncalc) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.spadnext.com/features/expressions.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.