From 127ca3042ce2be23bd0b07570154c81ac3fda432 Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <giann008@gmail.com>
Date: Thu, 13 Apr 2017 13:41:21 +0200
Subject: debug.getupvalue, debug.setupvalue

---
 README.md     |  4 ++--
 src/ldblib.js | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 2e53fc2..46a31ae 100644
--- a/README.md
+++ b/README.md
@@ -90,14 +90,14 @@
         - [x] debug.getlocal
         - [x] debug.getmetatable
         - [x] debug.getregistry
+        - [x] debug.getupvalue
         - [x] debug.setmetatable
+        - [x] debug.setupvalue
         - [x] debug.traceback
         - [ ] debug.gethook
-        - [ ] debug.getupvalue
         - [ ] debug.getuservalue
         - [ ] debug.sethook
         - [ ] debug.setlocal
-        - [ ] debug.setupvalue
         - [ ] debug.setuservalue
         - [ ] debug.upvalueid
         - [ ] debug.upvaluejoin
diff --git a/src/ldblib.js b/src/ldblib.js
index 2edc507..d3e3c7c 100644
--- a/src/ldblib.js
+++ b/src/ldblib.js
@@ -177,6 +177,29 @@ const db_getlocal = function(L) {
     }
 };
 
+/*
+** get (if 'get' is true) or set an upvalue from a closure
+*/
+const auxupvalue = function(L, get) {
+    let n = lauxlib.luaL_checkinteger(L, 2);  /* upvalue index */
+    lauxlib.luaL_checktype(L, 1, lua.CT.LUA_TFUNCTION);  /* closure */
+    let name = get ? lapi.lua_getupvalue(L, 1, n) : lapi.lua_setupvalue(L, 1, n);
+    if (name === null) return 0;
+    lapi.lua_pushstring(L, name);
+    lapi.lua_insert(L, -(get+1));  /* no-op if get is false */
+    return get + 1;
+};
+
+
+const db_getupvalue = function(L) {
+    return auxupvalue(L, 1);
+};
+
+const db_setupvalue = function(L) {
+    lauxlib.luaL_checkany(L, 3);
+    return auxupvalue(L, 0);
+};
+
 /*
 ** Check whether a given upvalue from a given closure exists and
 ** returns its index
@@ -214,7 +237,9 @@ const dblib = {
     "getlocal":     db_getlocal,
     "getmetatable": db_getmetatable,
     "getregistry":  db_getregistry,
+    "getupvalue":   db_getupvalue,
     "setmetatable": db_setmetatable,
+    "setupvalue":   db_setupvalue,
     "traceback":    db_traceback,
     "upvalueid":    db_upvalueid
 };
-- 
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