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typedef struct EnvEntry {
Object *symbol;
Object *value;
} EnvEntry;
typedef struct Environment {
struct Environment *parent;
EnvEntry *buf;
size_t size;
size_t cap;
} Environment;
static Environment *global_env;
#define ENV_BUF_CAP 8
Environment *
env_create(Environment *parent) {
Environment *env = malloc(sizeof(Environment));
env->parent = parent;
env->buf = NULL;
env->size = 0;
env->cap = ENV_BUF_CAP;
return env;
}
void
env_add_symbol(Environment *env, Object *symbol, Object *value) {
if (symbol->type != OBJ_TYPE_SYMBOL) {
error_push((Error){
.type = ERR_TYPE_RUNTIME,
.value = ERR_NOT_A_SYMBOL,
.line = 0,
.col = 0,
});
return;
}
if (env->buf == NULL) {
env->size = 0;
env->cap = ENV_BUF_CAP;
env->buf = malloc(env->cap * sizeof(EnvEntry));
} else if (env->size == env->cap) {
env->cap *= 2;
env->buf = realloc(env->buf, env->cap * sizeof(EnvEntry));
}
env->buf[env->size++] = (EnvEntry){symbol, value};
}
Object *
env_lookup(Environment *env, Object *symbol) {
while (env != NULL) {
for (size_t i = 0; i < env->size; i++) {
EnvEntry entry = env->buf[i];
if (obj_eq(symbol, entry.symbol)) {
return entry.value;
}
}
env = env->parent;
}
return obj_err;
}
Object *
env_update(Environment *env, Object *symbol, Object *value) {
while (env != NULL) {
for (size_t i = 0; i < env->size; i++) {
EnvEntry entry = env->buf[i];
if (obj_eq(symbol, entry.symbol)) {
env->buf[i].value = obj_duplicate(value);
return obj_nil;
}
}
env = env->parent;
}
error_push((Error){
.type = ERR_TYPE_RUNTIME,
.value = ERR_SYMBOL_NOT_FOUND,
});
return obj_err;
}
ssize_t
env_index_current(Environment *env, Object *symbol) {
for (size_t i = 0; i < env->size; i++) {
EnvEntry entry = env->buf[i];
if (obj_eq(symbol, entry.symbol)) {
return i;
}
}
return -1;
}
void
env_add_or_update_current(Environment *env, Object *symbol, Object *value) {
ssize_t index = env_index_current(env, symbol);
if (index == -1) {
env_add_symbol(env, obj_duplicate(symbol), obj_duplicate(value));
} else {
env->buf[index].value = obj_duplicate(value);
}
}
Environment *
env_extend(Environment *parent, Environment *extra) {
Environment *env = env_create(parent);
for (size_t i = 0; i < extra->size; i++) {
EnvEntry entry = extra->buf[i];
Environment *tmp = env;
bool found = false;
while (tmp != NULL) {
if (env_index_current(tmp, entry.symbol) != -1) {
found = true;
break;
}
tmp = tmp->parent;
}
if (!found) {
env_add_symbol(env, obj_duplicate(entry.symbol), obj_duplicate(entry.value));
}
}
return env;
}
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