diff options
| -rw-r--r-- | alisp.h | 3 | ||||
| -rw-r--r-- | constructor.c | 16 | ||||
| -rw-r--r-- | sys.c | 9 |
3 files changed, 24 insertions, 4 deletions
@@ -126,6 +126,9 @@ vec_t *as_vec(lisp_t *); #define CAR(L) (as_cons(L)->car) #define CDR(L) (as_cons(L)->cdr) +lisp_t *car(lisp_t *); +lisp_t *cdr(lisp_t *); + /// Pointer tagging scheme for lisps typedef enum Tag diff --git a/constructor.c b/constructor.c index 9db0330..e0fab52 100644 --- a/constructor.c +++ b/constructor.c @@ -46,3 +46,19 @@ lisp_t *intern(sys_t *sys, sv_t sv) char *str = sym_table_find(&sys->symtable, sv); return tag_sym(str); } + +lisp_t *car(lisp_t *lsp) +{ + if (!IS_TAG(lsp, CONS)) + return NIL; + else + return CAR(lsp); +} + +lisp_t *cdr(lisp_t *lsp) +{ + if (!IS_TAG(lsp, CONS)) + return NIL; + else + return CDR(lsp); +} @@ -43,12 +43,13 @@ void sys_cleanup(sys_t *sys) return; // Iterate through each element of memory - for (lisp_t *cell = sys->memory, *next = CDR(cell); cell; - cell = next, next = CDR(cell)) + for (lisp_t *cell = sys->memory, *next = cdr(cell); cell; + cell = next, next = cdr(next)) { // Only reason allocated exists is because we had to allocate memory on the - // heap for it. It's therefore - lisp_t *allocated = CAR(cell); + // heap for it. It's therefore enough to deal with only the allocated + // types. + lisp_t *allocated = car(cell); switch (get_tag(allocated)) { case TAG_CONS: |