A simple Scheme-like programming language interpreter implemented in Rust:
(define fib (lambda (n) (begin
; A recursive function
(define go (lambda (n a0 a1) (if
(<= n 0)
a0
(go (- n 1) a1 (+ a0 a1))
)))
(go n 0 1)
)))
(display (fib 80))(newline)
(define mutual (lambda (n) (begin
; Mutually recursive functions
(define dec (lambda (n) (check (- n 1))))
(define check (lambda (n) (if (<= n 0) 'done (dec n))))
(check n)
)))
(display (mutual 100000))(newline)cat examples/recursion.rsp | ./risp
23416728348467685
'doneThis is a project for learning purposes that does not follow any Scheme standard. The goal is to offer lexical scope, tail-call optimization, sharing of symbols, evaluate data as code and mostly efficient memory management in a simple way. The implementation is generic to allow selecting at compile time the types of booleans and numbers, as in this main program:
parser.parse_all_exps::<bool, i64>(input)It will also work for example with any other type that implements From<bool> and Into<bool> for booleans and i32 for numbers.
define, if, begin, lambda, quote, eval, and, and or.
The absence of set! allows to easily clean up the environment in some cases during evaluation.
=, >, <, >=, <=, +, *, -, eq?, display, newline, true and false.