code: def visitPairDef(self, ctx: jsgParser.PairDefContext):
          
          if ctx.name():          # Options 1 or 3
              self.visitChildren(ctx)
          else:
              self._type_reference = as_token(ctx)
              if ctx.ebnfSuffix():
                  self.visit(ctx.ebnfSuffix())
docs: pairDef: name COLON valueType ebnfSuffix? 
                       | idref ebnfSuffix?
                       | OPREN name (BAR? name)+ CPREN COLON valueType ebnfSuffix?