Fixed issue: #51

core/src/main/java/org/luaj/vm2/LuaValue.java

@@ -99,7 +99,7 @@ package org.luaj.vm2;
  * {@link #INDEX}, {@link #NEWINDEX}, {@link #CALL}, {@link #MODE}, {@link #METATABLE},
  * {@link #ADD}, {@link #SUB}, {@link #DIV}, {@link #MUL}, {@link #POW},
  * {@link #MOD}, {@link #UNM}, {@link #LEN}, {@link #EQ}, {@link #LT},
- * {@link #LE}, {@link #TOSTRING}, and {@link #CONCAT}.
+ * {@link #LE}, {@link #TOSTRING}, {@link #CONCAT}, {@link #PAIRS}, and {@link #IPAIRS}.
  * 
  * @see org.luaj.vm2.libs.jse.JsePlatform
  * @see org.luaj.vm2.libs.jme.JmePlatform
@@ -264,6 +264,12 @@ public class LuaValue extends Varargs {
 	/** LuaString constant with value "__concat" for use as metatag */
 	public static final LuaString CONCAT      = valueOf("__concat");
 
+	/** LuaString constant with value "__pairs" for use as metatag */
+	public static final LuaString PAIRS       = valueOf("__pairs");
+
+	/** LuaString constant with value "__ipairs" for use as metatag */
+	public static final LuaString IPAIRS      = valueOf("__ipairs");
+	
 	/** LuaString constant with value "" */
 	public static final LuaString EMPTYSTRING = valueOf("");
 

core/src/main/java/org/luaj/vm2/libs/BaseLib.java

@@ -399,7 +399,9 @@ public class BaseLib extends TwoArgFunction implements ResourceFinder {
 			this.next = next;
 		}
 		public Varargs invoke(Varargs args) {
-				return varargsOf( next, args.checktable(1), NIL );
+			LuaValue table = args.arg1();
+			LuaValue h = table.metatag(PAIRS);
+			return h.isnil()? varargsOf(next, table.checktable(), NIL): h.invoke(table);
 		}
 	}
 	
@@ -407,7 +409,9 @@ public class BaseLib extends TwoArgFunction implements ResourceFinder {
 	static final class ipairs extends VarArgFunction {
 		inext inext = new inext();
 		public Varargs invoke(Varargs args) {
-			return varargsOf( inext, args.checktable(1), ZERO );
+			LuaValue table = args.arg1();
+			LuaValue h = table.metatag(IPAIRS);
+			return h.isnil()? varargsOf(inext, table.checktable(), ZERO): h.invoke(table);
 		}
 	}
 	

jse/src/test/java/org/luaj/vm2/FragmentsTest.java

@@ -331,6 +331,48 @@ public class FragmentsTest extends TestSuite {
 			}
 		}
 
+		public void testPairsUsesMetatableOverride() {
+			runFragment(
+				LuaValue.varargsOf(new LuaValue[] {
+					LuaValue.valueOf("k"),
+					LuaValue.valueOf("v")
+				}),
+				"local t = setmetatable({}, {\n" +
+				"  __pairs = function(self)\n" +
+				"    local done = false\n" +
+				"    return function()\n" +
+				"      if done then return nil end\n" +
+				"      done = true\n" +
+				"      return 'k', 'v'\n" +
+				"    end, self, nil\n" +
+				"  end\n" +
+				"})\n" +
+				"for k, v in pairs(t) do\n" +
+				"  return k, v\n" +
+				"end\n");
+		}
+
+		public void testIpairsUsesMetatableOverride() {
+			runFragment(
+				LuaValue.varargsOf(new LuaValue[] {
+					LuaValue.valueOf(7),
+					LuaValue.valueOf("x")
+				}),
+				"local t = setmetatable({}, {\n" +
+				"  __ipairs = function(self)\n" +
+				"    local done = false\n" +
+				"    return function()\n" +
+				"      if done then return nil end\n" +
+				"      done = true\n" +
+				"      return 7, 'x'\n" +
+				"    end, self, 0\n" +
+				"  end\n" +
+				"})\n" +
+				"for i, v in ipairs(t) do\n" +
+				"  return i, v\n" +
+				"end\n");
+		}
+
 		public void testTableMove() {
 			runFragment(
 				LuaValue.varargsOf(new LuaValue[] {