package objects type BuiltinFunc func(args ...Object) (ret Object, err error) var Builtins = []struct { Name string Func BuiltinFunc }{ { Name: "print", Func: builtinPrint, }, { Name: "len", Func: builtinLen, }, { Name: "copy", Func: builtinCopy, }, { Name: "append", Func: builtinAppend, }, }