1 files changed, 50 insertions, 3 deletions

diff --git a/src/lobject.js b/src/lobject.js
index f926e85..9790d23 100644
--- a/src/lobject.js
+++ b/src/lobject.js
@@ -10,6 +10,7 @@ const lstring = require('./lstring.js');
 const luaconf = require('./luaconf.js');
 const lvm     = require('./lvm.js');
 const llimit  = require('./llimit.js');
+const ltm     = require('./ltm.js');
 const CT      = defs.constant_types;
 const char    = defs.char;
 
@@ -547,14 +548,60 @@ const numarith = function(L, op, v1, v2) {
     }
 };
 
-module.exports.LUA_TPROTO        = LUA_TPROTO;
-module.exports.LUA_TDEADKEY      = LUA_TDEADKEY;
+const luaO_arith = function(L, op, p1, p2, res) {
+    switch (op) {
+        case defs.LUA_OPBAND: case defs.LUA_OPBOR: case defs.LUA_OPBXOR:
+        case defs.LUA_OPSHL: case defs.LUA_OPSHR:
+        case defs.LUA_OPBNOT: {  /* operate only on integers */
+            let i1 = lvm.tointeger(p1);
+            let i2 = lvm.tointeger(p2);
+            if (i1 !== false && i2 !== false) {
+                res.type  = CT.LUA_TNUMINT;
+                res.value = intarith(L, op, i1, i2);
+                return;
+            }
+            else break;  /* go to the end */
+        }
+        case defs.LUA_OPDIV: case defs.LUA_OPPOW: {  /* operate only on floats */
+            let n1 = lvm.tonumber(p1);
+            let n2 = lvm.tonumber(p2);
+            if (n1 !== false && n2 !== false) {
+                res.type  = CT.LUA_TNUMFLT;
+                res.value = numarith(L, op, n1, n2);
+                return;
+            }
+            else break;  /* go to the end */
+        }
+        default: {  /* other operations */
+            let n1 = lvm.tonumber(p1);
+            let n2 = lvm.tonumber(p2);
+            if (p1.ttisinteger() && p2.ttisinteger()) {
+                res.type  = CT.LUA_TNUMINT;
+                res.value = intarith(L, op, p1.value, p2.value);
+                return;
+            }
+            else if (n1 !== false && n2 !== false) {
+                res.type  = CT.LUA_TNUMFLT;
+                res.value = numarith(L, op, n1, n2);
+                return;
+            }
+            else break;  /* go to the end */
+        }
+    }
+    /* could not perform raw operation; try metamethod */
+    assert(L !== null);  /* should not fail when folding (compile time) */
+    ltm.luaT_trybinTM(L, p1, p2, res, (op - defs.LUA_OPADD) + ltm.TMS.TM_ADD);
+};
+
+
 module.exports.CClosure          = CClosure;
 module.exports.LClosure          = LClosure;
+module.exports.LUA_TDEADKEY      = LUA_TDEADKEY;
+module.exports.LUA_TPROTO        = LUA_TPROTO;
 module.exports.LocVar            = LocVar;
 module.exports.TValue            = TValue;
 module.exports.UTF8BUFFSZ        = UTF8BUFFSZ;
-module.exports.intarith          = intarith;
+module.exports.luaO_arith        = luaO_arith;
 module.exports.luaO_chunkid      = luaO_chunkid;
 module.exports.luaO_hexavalue    = luaO_hexavalue;
 module.exports.luaO_int2fb       = luaO_int2fb;