Any time one is within a form tag (with a MICfieldspace specified) or within a MICfieldspace tag, there will be a Perl object, $fs, available. It is through this object that one may access variables (which have been MICdefine'd) of the current fieldspace. This interface to this object is not totally defined by the MIC specification, though some of the methods on it are defined in 9.2, C.1 and in the documentation for the implementation of the the MIC compliant fieldspace object that is being utilized.
This object is used to access fields and the informaiton within those fields. It as also used to ascertain certain state questions, especially regarding errors, about the fieldspace. As far as a MIC-coder's code is concerned, the fieldspace should be used to get information, but not change it. Generally, when the MIC-coder is changing information (as in setting default values), they will be presented with the field itself. The MIC-coder should never change state information directly through the fieldspace object except in MICverifies. It is hoped that eventually, this will even be unnecessary.