From ed24912b2bfe3666a51760ca4b8e1a29ada12e25 Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <giann008@gmail.com>
Date: Mon, 6 Feb 2017 22:45:51 +0100
Subject: VARARG

---
 src/lvm.js   | 19 +++++++++++++++++++
 tests/lvm.js | 26 ++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/src/lvm.js b/src/lvm.js
index e0901c5..98dfa76 100644
--- a/src/lvm.js
+++ b/src/lvm.js
@@ -449,6 +449,25 @@ class LuaVM {
                     break;
                 }
                 case "OP_VARARG": {
+                    let b = i.B - 1;
+                    let n = base - ci.funcOff - cl.p.numparams - 1;
+                    let j
+
+                    if (n < 0) /* less arguments than parameters? */
+                        n = 0; /* no vararg arguments */
+
+                    if (b < 0) {
+                        b = n;  /* get all var. arguments */
+                        base = ci.u.l.base;
+                        ra = this.RA(i); /* previous call may change the stack */
+                        L.top = ra + n;
+                    }
+
+                    for (j = 0; j < b && j < n; j++)
+                        L.stack[ra + j] = L.stack[base - n - j];
+
+                    for (; j < b; j++) /* complete required results with nil */
+                        L.stack[ra + j] = new TValue(CT.LUA_TNIL, null);
                     break;
                 }
                 case "OP_EXTRAARG": {
diff --git a/tests/lvm.js b/tests/lvm.js
index c454bcf..62f9fff 100644
--- a/tests/lvm.js
+++ b/tests/lvm.js
@@ -239,6 +239,32 @@ test('TAILCALL', function (t) {
         vm.execute();
     }, "Program executed without errors");
 
+    t.strictEqual(
+        vm.L.stack[vm.L.top - 1].value,
+        3,
+        "Program output is correct"
+    );
+});
+
+
+test('VARARG', function (t) {
+    let luaCode = `
+        local f = function (a, b)
+            return a + b
+        end
+
+        return f(1,2)
+    `, vm;
+    
+    t.plan(2);
+
+    t.comment("Running following code: \n" + luaCode);
+
+    t.doesNotThrow(function () {
+        vm = getVM(luaCode);
+        vm.execute();
+    }, "Program executed without errors");
+
     t.strictEqual(
         vm.L.stack[vm.L.top - 1].value,
         3,
-- 
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