ive (parenthetic) function are set off by commas; appositives which serve a restrictive (necessary) function are not."), 917 P.2d 95 (Wash. 1996); Xcel Corp. v. Dir., Div. of Taxation, 4 M. Tax 85, 89 (E. Tax Ct.) ("It is an elementary rule of grammar that commas are used to set off nonrestrictive apposi