The gogyou is a library written at pure ruby that provides auxiliary features of binary data operation for ruby. The C-liked struct, union and multidimensional array definition are posible in ruby syntax. Available features: (1) nested struct and union with anonymous field (2) multidimensional array (3) field of variable array (4) const field (5) packed field (6) user definition types (7) (EXPERIMENTAL AND LIMITATION FEATURE) pointer