Petite Chez Scheme Version 9.5
Copyright 1984-2017 Cisco Systems, Inc.

> (+ (/ 3 5) (/ 6 7))
51/35
> six
Exception: variable six is not bound
> (define six 6)
> (+ six 7)
13
> (list 2 3 4)
(2 3 4)
> (define a (+ 2 3 4)
)
> '(2 3 4)
(2 3 4)
> '(2 six 4)
(2 six 4)
> (list 2 six 4)
(2 6 4)
> (define b (cons 1 a))
> b
(1 . 9)
> a
9
> (define c (list 2 3 4))
> (define d (cons 1 c))
> d
(1 2 3 4)
> (= 2 3 4 5)
#f
> (+ 2 3 4 5)
14
> c
(2 3 4)
> d
(1 2 3 4)
> (car c)
2
> (cdr)
Exception: incorrect argument count in call (cdr)
> (cdr c)
(3 4)
> (car (cdr c))
3
> (cadr c)
3
> (caddr c)
4
> (cadddr c)
Exception in cadddr: incorrect list structure (2 3 4)
> (caddddr c)
Exception: variable caddddr is not bound
> +
#<procedure +>
> (define times3
  (lambda (n)
    (* n 3)))
> (times3 5)
15
> (define times6
  (lambda (n)
    (+ (times3 n) (times3 n))))
> (trace times3 times6)
(times3 times6)
> (times6 7)
|(times6 7)
| (times3 7)
| 21
| (times3 7)
| 21
|42
42
> (untrace)
(times3 times6)
> (define fact
  (lambda (n)
    (if (zero? n)
	1
	(* n (fact (- n 1))))))
> (fact 5)
120
> (fact 1000)
402387260077093773543702433923003985719374864210714632543799910429938512398629020592044208486969404800479988610197196058631666872994808558901323829669944590997424504087073759918823627727188732519779505950995276120874975462497043601418278094646496291056393887437886487337119181045825783647849977012476632889835955735432513185323958463075557409114262417474349347553428646576611667797396668820291207379143853719588249808126867838374559731746136085379534524221586593201928090878297308431392844403281231558611036976801357304216168747609675871348312025478589320767169132448426236131412508780208000261683151027341827977704784635868170164365024153691398281264810213092761244896359928705114964975419909342221566832572080821333186116811553615836546984046708975602900950537616475847728421889679646244945160765353408198901385442487984959953319101723355556602139450399736280750137837615307127761926849034352625200015888535147331611702103968175921510907788019393178114194545257223865541461062892187960223838971476088506276862967146674697562911234082439208160153780889893964518263243671616762179168909779911903754031274622289988005195444414282012187361745992642956581746628302955570299024324153181617210465832036786906117260158783520751516284225540265170483304226143974286933061690897968482590125458327168226458066526769958652682272807075781391858178889652208164348344825993266043367660176999612831860788386150279465955131156552036093988180612138558600301435694527224206344631797460594682573103790084024432438465657245014402821885252470935190620929023136493273497565513958720559654228749774011413346962715422845862377387538230483865688976461927383814900140767310446640259899490222221765904339901886018566526485061799702356193897017860040811889729918311021171229845901641921068884387121855646124960798722908519296819372388642614839657382291123125024186649353143970137428531926649875337218940694281434118520158014123344828015051399694290153483077644569099073152433278288269864602789864321139083506217095002597389863554277196742822248757586765752344220207573630569498825087968928162753848863396909959826280956121450994871701244516461260379029309120889086942028510640182154399457156805941872748998094254742173582401063677404595741785160829230135358081840096996372524230560855903700624271243416909004153690105933983835777939410970027753472000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> (trace fact)
(fact)
> (fact 5)
|(fact 5)
| (fact 4)
| |(fact 3)
| | (fact 2)
| | |(fact 1)
| | | (fact 0)
| | | 1
| | |1
| | 2
| |6
| 24
|120
120
> (define nth-element
  (lambda (ls n)
    (cond [(null? ls) "error"]
	  [(zero? n) (car ls)]
	  [else (nth-element (cdr ls) (- n 1))])))
> (nth-element '(a b c d e) 3)
d
> (nth-element '(a b c d e) 7)
"error"
>