"~{pn}" -> case (sortJsonMsg_direction sjm) of 
    "ASC"  -> orderBy [ asc (~{vn} ~{projectField (ctxIsMaybe ctx vn)} ~{entityFieldTypeName e f}) ] 
    "DESC" -> orderBy [ desc (~{vn} ~{projectField (ctxIsMaybe ctx vn)} ~{entityFieldTypeName e f}) ] 
    _      -> return ()