What is the primary function of the `eval` command in SPL?

The primary function of the eval command in SPL (Search Processing Language) is to modify and create new fields within your search results. This command allows users to perform calculations, manipulate strings, and execute conditional logic to derive new values based on existing data. For instance, you can use eval to create a new field that represents the total price from quantity and unit price fields, or to transform data formats and apply functions such as if, case, and mathematical operations.

This ability to dynamically alter the data set during the search process is crucial for advanced analytics and reporting, enabling users to tailor their results to fit specific needs or to extract meaningful insights directly from the raw data.