Distinction between repeal and omission: repeal preserves prior rights and proceedings, omission does not without a saving provision. Section 6 of the General Clauses Act preserves effects of a repealed enactment-protecting prior operations, rights, liabilities, penalties and ongoing proceedings-unless a contrary intention appears; by contrast, an omission is treated as if the provision never existed and does not attract those protective effects unless an express saving or pari-materia provision preserves pending proceedings.