From 431b47377d8c5bc6b10ae6e7bd52d5338b3b8ba0 Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Wed, 11 Jun 2014 11:03:12 -0700
Subject: [PATCH] feat(library/kernel_bindings): add 'set_env/set_environment'
 commands for updating the global environment

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
---
 src/library/kernel_bindings.cpp | 11 ++++++++++-
 src/library/kernel_bindings.h   |  5 +++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/library/kernel_bindings.cpp b/src/library/kernel_bindings.cpp
index 5cd73e1dc..d780dacb1 100644
--- a/src/library/kernel_bindings.cpp
+++ b/src/library/kernel_bindings.cpp
@@ -1300,12 +1300,14 @@ void set_global_environment(lua_State * L, environment const & env) {
     lua_settable(L, LUA_REGISTRYINDEX);
 }
 
-set_environment::set_environment(lua_State * L, environment const & env) {
+set_environment::set_environment(lua_State * L, environment & env):
+    m_env(env) {
     m_state = L;
     set_global_environment(L, env);
 }
 
 set_environment::~set_environment() {
+    m_env = get_global_environment(m_state);
     lua_pushlightuserdata(m_state, static_cast<void *>(&g_set_environment_key));
     lua_pushnil(m_state);
     lua_settable(m_state, LUA_REGISTRYINDEX);
@@ -1325,6 +1327,11 @@ int get_environment(lua_State * L) {
     return push_environment(L, get_global_environment(L));
 }
 
+int set_environment(lua_State * L) {
+    set_global_environment(L, to_environment(L, 1));
+    return 0;
+}
+
 static void environment_migrate(lua_State * src, int i, lua_State * tgt) {
     push_environment(tgt, to_environment(src, i));
 }
@@ -1342,6 +1349,8 @@ static void open_environment(lua_State * L) {
     SET_GLOBAL_FUN(environment_pred,       "is_environment");
     SET_GLOBAL_FUN(get_environment,        "get_environment");
     SET_GLOBAL_FUN(get_environment,        "get_env");
+    SET_GLOBAL_FUN(set_environment,        "set_environment");
+    SET_GLOBAL_FUN(set_environment,        "set_env");
     SET_GLOBAL_FUN(import_modules,         "import_modules");
     SET_GLOBAL_FUN(import_hott_modules,    "import_hott_modules");
     SET_GLOBAL_FUN(export_module,          "export_module");
diff --git a/src/library/kernel_bindings.h b/src/library/kernel_bindings.h
index 1fdd5459a..11c717021 100644
--- a/src/library/kernel_bindings.h
+++ b/src/library/kernel_bindings.h
@@ -51,9 +51,10 @@ void set_global_environment(lua_State * L, environment const & env);
    with an environment object.
 */
 class set_environment {
-    lua_State * m_state;
+    environment & m_env;
+    lua_State *   m_state;
 public:
-    set_environment(lua_State * L, environment const & env);
+    set_environment(lua_State * L, environment & env);
     ~set_environment();
 };