scheme Chibi-Scheme is a very small but mostly complete R5RS Scheme implementation using a reasonably fast custom VM. Chibi-Scheme tries as much as possible not to trade its small size by cutting corners, and provides full continuations, both low and high-level hygienic macros based on syntactic-closures, string ports and exceptions. Chibi-Scheme is written in highly portable C and supports multiple VM instances to run simultaneously. Use the old Boehm-Demers-Weiser conservative garbage collector instead of the new chibi-scheme built-in precise collector.