; test_error.lisp — runtime errors. Each form should produce
; `error: <message>` on stderr; the REPL keeps going and prints
; surviving results on stdout.
;
; Run:  cat test_error.lisp | ./lisp

undefined-symbol                 ; error: unbound symbol
(car 1)                          ; error: car: not a pair
(cdr '())                        ; error: cdr: not a pair
(/ 5 0)                          ; error: divide by zero
(mod 7 0)                        ; error: mod by zero
(+ 'a 'b)                        ; error: expected number
(car)                            ; error: car: need 1 arg
(cons 1)                         ; error: cons: need 2 args

; sanity: the REPL recovers — these should print normally.
(+ 1 2)                          ; => 3
"still alive"                    ; => "still alive"