Description of the illustration field

field_list :==
 
(column_name { dgen_fld_spec 
| scalar_fld_spec 
| col_obj_fld_spec 
| collection_fld_spec
| filler_fld_spec }
)
[(, column_name { d_gen_fld_spec 
| scalar_fld_spec 
| col_obj_fld_spec 
| collection_fld_spec
| filler_fld_spec }
)]...