Hi Vyzo, The core prelude ( https://github.com/vyzo/gerbil/blob/master/src/gerbil/prelude/core.ss) defines some extensions to |import| and |export|. Bumped into studying this in proto.ss, which contains (export ... (struct-out !rpc ...) ...). struct-out can be understood from its use - it's for exporting a structure with its constructors, accessors, mutators. (struct-out's definition code is totally unreadable to me though.) All of these are undocumented, may you want to comment on what they are for also with a single use example (or add to some documentation section in your guide)? Thanks! Adam defsyntax-for-import-export:s: - for-syntax - for-template defsyntax-for-import:s:: - only-in - except-in - rename-in - prefix-in - group-in defsyntax-for-export:s: - except-out - rename-out - prefix-out - struct-out