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typedef enum ObjectType {
OBJ_TYPE_FIXNUM,
OBJ_TYPE_BOOL,
OBJ_TYPE_NIL,
OBJ_TYPE_SYMBOL,
OBJ_TYPE_STRING,
OBJ_TYPE_PAIR,
OBJ_TYPE_PROCEDURE,
} ObjectType;
typedef struct Object {
ObjectType type;
union {
// OBJ_TYPE_FIXNUM
ssize_t fixnum;
// OBJ_TYPE_BOOL
bool boolean;
// OBJ_TYPE_STRING
struct {
char *string;
size_t string_n;
};
// OBJ_TYPE_PAIR
struct {
struct Object *car;
struct Object *cdr;
};
// OBJ_TYPE_SYMBOL
struct {
char *symbol;
size_t symbol_n;
};
// OBJ_TYPE_PROCEDURE
struct Object *(*proc)(struct Object *args);
};
} Object;
//
// Singletons.
//
Object *obj_nil;
Object *obj_true;
Object *obj_false;
//
// Constructors.
//
Object *
make_fixnum(ssize_t num) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_FIXNUM;
obj->fixnum = num;
return obj;
}
Object *
make_boolean(bool b) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_BOOL;
obj->boolean = b;
return obj;
}
Object *
make_empty_string(void) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_STRING;
obj->string = NULL;
obj->string_n = 0;
return obj;
}
void
append_string(Object *string, StringView sv) {
assert(string != NULL);
assert(string->type == OBJ_TYPE_STRING);
if (sv.n == 0) {
return;
}
string->string = realloc(string->string, (string->string_n + sv.n) * sizeof(char));
memcpy(string->string + string->string_n, sv.start, sv.n);
string->string_n += sv.n;
}
Object *
make_symbol(const char *str, size_t n) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_SYMBOL;
obj->string = malloc(sizeof(char) * n);
memcpy(obj->string, str, n);
obj->string_n = n;
return obj;
}
Object *
make_empty_list(void) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_NIL;
return obj;
}
Object *
make_procedure(Object *(*proc)(struct Object *args)) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_PROCEDURE;
obj->proc = proc;
return obj;
}
Object *
make_pair(Object *car, Object *cdr) {
Object *obj = malloc(sizeof(Object));
obj->type = OBJ_TYPE_PAIR;
obj->car = car;
obj->cdr = cdr;
return obj;
}
bool
symbol_eq(Object *a, Object *b) {
if (a->type != b->type || a->type != OBJ_TYPE_SYMBOL || a->symbol_n != b->symbol_n) {
return false;
}
for (size_t i = 0; i < a->symbol_n; i++) {
if (a->symbol[i] != b->symbol[i]) {
return false;
}
}
return true;
}
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