Note that the BLC self-interpreter mentioned in another comment does not get the reader for free, having to parse lambda terms (including numbers written in una

Note that the BLC self-interpreter mentioned in another comment does not get the reader for free, having to parse lambda terms (including numbers written in unary) from a stream of bits. It does get a garbage collector for free. It is accompanied by a BLC interpreter written in 25 lines of obfuscated C that does include a reference counting garbage collector.