原文
Lisp in Rust trait system.
- 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.
- Recursive functions
- Global and lexical environments (via
letbindings) - Function calls
applyproperly workingcall/ec
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 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()
);