In my experience, not only /value/ but also /name/ and even /filename/ can be (SIMPLE-ARRAY EXTENDED-CHAR *). So I think it's necessary to (SETF (F-S-E-F S) E-F-OUT) before DOLIST in MAKE-FORM-DATA-FUNCTION. And I don't think it's necessary to (SETF (F-S-E-F S) +LATIN-1+).
In my experience, not only /value/ but also /name/ and even /filename/ can be (SIMPLE-ARRAY EXTENDED-CHAR *). So I think it's necessary to (SETF (F-S-E-F S) E-F-OUT) before DOLIST in MAKE-FORM-DATA-FUNCTION. And I don't think it's necessary to (SETF (F-S-E-F S) +LATIN-1+).