1 files changed, 28 insertions, 1 deletions
diff --git a/src/lapi.js b/src/lapi.js
index 32a9873..a11dbca 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -429,6 +429,30 @@ const lua_createtable = function(L, narray, nrec) {
     assert(L.top <= L.ci.top, "stack overflow");
 };
 
+const aux_upvalue = function(fi, n) {
+    switch(fi.ttype()) {
+        case CT.LUAT_TCCL: {  /* C closure */
+            let f = fi.value;
+            if (!(1 <= n && n <= f.nupvalues)) return null;
+            return {
+                name: "",
+                val: f.upvalue[n-1]
+            };
+        }
+        case CT.LUA_TLCL: {  /* Lua closure */
+            let f = fi.value;
+            let p = f.p;
+            if (!(1 <= n && n <= p.upvalues.length)) return null;
+            let name = p.upvalues[n-1].name;
+            return {
+                name: name ? name : "(*no name)",
+                val: f.upvals[n-1].val()
+            };
+        }
+        default: return null;  /* not a closure */
+    }
+};
+
 const lua_setupvalue = function(L, funcindex, n) {
     let fi = index2addr(L, funcindex);
     assert(1 < L.top - L.ci.funcOff, "not enough elements in the stack");
@@ -437,7 +461,9 @@ const lua_setupvalue = function(L, funcindex, n) {
     let val = aux.val;
     if (name) {
         L.top--;
-        setobj(L, val, L.top);
+        // TODO: what if it's not a pure TValue (closure, table)
+        val.type = L.stack[L.top].type;
+        val.value = L.stack[L.top].value;
     }
     return name;
 };
@@ -866,6 +892,7 @@ module.exports.lua_seti            = lua_seti;
 module.exports.lua_setmetatable    = lua_setmetatable;
 module.exports.lua_settable        = lua_settable;
 module.exports.lua_settop          = lua_settop;
+module.exports.lua_setupvalue      = lua_setupvalue;
 module.exports.lua_status          = lua_status;
 module.exports.lua_stringtonumber  = lua_stringtonumber;
 module.exports.lua_toboolean       = lua_toboolean;