The API request read in is evaluated according to the SubL "eval" protocol. More precisely, the SubL function EVAL is called on the form in order to produce a single SubL result. This result is outputted using the output message protocol. If a function returns multiple values, only the first value is used, however the SubL function MULTIPLE-VALUE-LIST can be used to gather multiple values into a single list.
If an error condition occurs during evaluation, the evaluation is aborted and a string representing the error condition is used as the result of the evaluation.