, {1})           --> a = 1, b = 0
ffi.new("struct foo", {1,2})         --> a = 1, b = 2
ffi.new("struct foo", {[0]=1,2})     --> a = 1, b = 2
ffi.new("struct foo", {b=2})         --> a = 0, b = 2
ffi.new("struct foo", {a=1,b=2,c=3}) --> a = 1, b = 2  'c' is ignored

ffi.new("union bar", {})        --> i = 0, d = 0.0
ffi.new("union bar", {1})       --> i = 1, d = ?
ffi.new("union bar", {[0]=1,2}) --> i = 1, d = ?    '2' is ignored
ffi.new("union bar", {d=2})     --> i = ?, d = 2.0

ffi.new("struct nested", {