A formal description of packedobjects is as follows:
packedobjects is a data encoding tool based on the telecommunications standard Packed Encoding Rules (PER). An abstract syntax language is used to define a protocol specification. packedobjects uses the Scheme programming language to represent the protocol specification within a symbolic expression (s-expression).
Moore, J. “PACKEDOBJECTS”, Proceedings of WINSYS 2006, International Conference on Wireless Information Networks and Systems, August 2006, pp. 310-314
Less formally, packedobjects is a “bit stuffing” tool driven by a high level syntax. Rather than use ASN.1, packedobjects uses s-expressions as the high level syntax to represent a protocol description. The advantage of s-expressions is they are native to languages such as Scheme. At the time the project was conceived there were no open source solutions supporting unaligned PER. packeobjects was designed for projects that would benefit from a tool that was positioned in between hand encoding and formal telecommunications standards.