GitHub - playX18/lisp-in-types: Lisp implemented inside Rust trait system

Lisp in Rust trait system. Limitations

Each symbol must be manually declared via defkey!() macro Numbers cannot be negative Numbers are only in range of 0..8192, you can modify build.rs to generate more natural numbers but then you have to run with RUST_MIN_STACK increased. No (defmacro ...) No eval I have not tested it extensively.

Features

Recursive functions Global and lexical environments (via let bindings) Function calls apply properly working call/ec

Example Factorial: type DefFac = expr!(defun SymFac (SymN) (if (= SymN 0) 1 (* SymN (SymFac (- SymN 1)))));

type Global2 = <DefFac as EvalForm<Global1, Lex0>>::GlobalOut; type Fac5 = EvalValue<expr!((SymFac 5)), Global2, Lex0>; assert_same::<Fac5, N120>();

println!("(fac 5) => {:?}", <Fac5 as ToRtValue>::to_rt()); call/ec (delimited) // call/ec demo (escape continuation, explicit tag): // (call/ec cc (lambda (k) (+ 1 (k 5)))) => 5 defkey!(SymCC, N10); defkey!(SymK, N11); type CallECExpr = expr!((call/ec SymCC (lambda (SymK) (+ 1 (SymK 5))))); type CallECResult = EvalValue<CallECExpr, Global1, Lex0>; assert_same::<CallECResult, N5>(); println!( "(call/ec cc (lambda (k) (+ 1 (k 5)))) => {:?}", <CallECResult as ToRtValue>::to_rt() );