--- a/core/src/luan/impl/LuanStateImpl.java	Tue Jul 14 17:40:48 2015 -0600
+++ b/core/src/luan/impl/LuanStateImpl.java	Thu Jul 16 15:14:31 2015 -0600
@@ -12,6 +12,7 @@
 import luan.LuanElement;
 import luan.LuanSource;
 import luan.DeepCloner;
+import luan.StackTraceElement;
 
 
 final class LuanStateImpl extends LuanState {
@@ -124,4 +125,66 @@
 		return frame.closure.fnDef.el().source;
 	}
 
+
+
+	@Override public boolean isLessThan(Object o1,Object o2) throws LuanException {
+		if( o1 instanceof Number && o2 instanceof Number ) {
+			Number n1 = (Number)o1;
+			Number n2 = (Number)o2;
+			return n1.doubleValue() < n2.doubleValue();
+		}
+		if( o1 instanceof String && o2 instanceof String ) {
+			String s1 = (String)o1;
+			String s2 = (String)o2;
+			return s1.compareTo(s2) < 0;
+		}
+		LuanFunction fn = getBinHandler("__lt",o1,o2);
+		if( fn != null )
+			return checkBoolean( Luan.first(fn.call(this,new Object[]{o1,o2})) );
+		throw new LuanException(this, "attempt to compare " + Luan.type(o1) + " with " + Luan.type(o2) );
+	}
+
+	LuanFunction getBinHandler(String op,Object o1,Object o2) throws LuanException {
+		if( o1 instanceof LuanTable ) {
+			LuanFunction f1 = getHandlerFunction(op,(LuanTable)o1);
+			if( f1 != null )
+				return f1;
+		}
+		return o2 instanceof LuanTable ? getHandlerFunction(op,(LuanTable)o2) : null;
+	}
+
+	LuanFunction getHandlerFunction(String op,LuanTable t) throws LuanException {
+		Object f = t.getHandler(op);
+		if( f == null )
+			return null;
+		return checkFunction(f);
+	}
+
+	Boolean checkBoolean(Object obj,LuanElement el) throws LuanException {
+		push(el,null);
+		try {
+			return checkBoolean(obj);
+		} finally {
+			pop();
+		}
+	}
+
+	String toString(Object obj,LuanElement el) throws LuanException {
+		push(el,null);
+		try {
+			return toString(obj);
+		} finally {
+			pop();
+		}
+	}
+
+	void push(LuanElement el,String fnName) {
+		if( el == null )  throw new RuntimeException();
+		stackTrace.add( new StackTraceElement(el,fnName) );
+	}
+
+	void pop() {
+		stackTrace.remove(stackTrace.size()-1);
+	}
+
 }