Another functional language that can be concisely implemented [1] in Python is Binary Lambda Calculus, with a large part of the code dealing with BLC's pure I/O

Another functional language that can be concisely implemented [1] in Python is Binary Lambda Calculus, with a large part of the code dealing with BLC's pure I/O model. Instead of using an association list for variable lookup, it uses de-Bruijn indices to index the environment array. The same page shows implementations in 9 other languages, with BLC's self interpreter being the most concise at 232 bits (29 bytes), which includes a parser and tokenizer. [1] https://rosettacode.org/wiki/Universal_Lambda_Machine#Python https://rosettacode.org/wiki/Universal_Lambda_Machine#Python