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//
// Environment.
//
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};
}
bool
obj_eq(Object *a, Object* b) {
if (a->type != b->type) {
return false;
}
switch (a->type) {
case OBJ_TYPE_FIXNUM: {
return a->fixnum == b->fixnum;
} break;
case OBJ_TYPE_STRING: {
if (a->string_n != b->string_n) {
return false;
}
for (size_t i = 0; i < a->string_n; i++) {
if (a->string[i] != b->string[i]) {
return false;
}
}
} break;
case OBJ_TYPE_SYMBOL: {
if (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;
}
}
} break;
case OBJ_TYPE_PAIR: {
// TODO: needs evaluation of parameters...
} break;
default: {
return a == b;
} break;
}
return true;
}
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;
}
// TODO: Free env function.
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