diff options
| -rw-r--r-- | lisp.c | 19 |
1 files changed, 14 insertions, 5 deletions
@@ -66,16 +66,25 @@ value *cons(value *car, value *cdr) { } value *car(value *cons) { - //TODO: more robust implementation with error catching - return cons->as.pair.car; + if (cons->type == VT_PAIR) { + return cons->as.pair.car; + } + printf("not a pair: "); + print_value(cons); + printf("\n"); + return make_nil(); } value *cdr(value *cons) { - //TODO: more robust implementation with error catching - return cons->as.pair.cdr; + if (cons->type == VT_PAIR) { + return cons->as.pair.cdr; + } + printf("not a pair: "); + print_value(cons); + printf("\n"); + return make_nil(); } - void *print_value(value *val){ char *str; switch (val->type) { |