1 files changed, 51 insertions, 1 deletions

diff --git a/src/bootstrap/environment.c b/src/bootstrap/environment.c
index 99dd7fd..e111753 100644
--- a/src/bootstrap/environment.c
+++ b/src/bootstrap/environment.c
@@ -60,8 +60,27 @@ env_lookup(Environment *env, Object *symbol) {
     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_symbol_index_in_current_env(Environment *env, Object *symbol) {
+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)) {
@@ -70,3 +89,34 @@ env_symbol_index_in_current_env(Environment *env, Object *symbol) {
     }
     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;
+        ssize_t idx = -1;
+        while (tmp != NULL) {
+            idx = env_index_current(tmp, entry.symbol);
+            if (idx != -1) {
+                break;
+            }
+            tmp = tmp->parent;
+        }
+        if (idx == -1) {
+            env_add_symbol(env, obj_duplicate(entry.symbol), obj_duplicate(entry.value));
+        }
+    }
+    return env;
+}