--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/luan/LuanState.java	Fri Dec 28 03:29:12 2012 +0000
@@ -0,0 +1,113 @@
+package luan;
+
+import java.util.List;
+import java.util.ArrayList;
+
+
+public abstract class LuanState {
+	private final LuanTable global = new LuanTable();
+	private final List<MetatableGetter> mtGetters = new ArrayList<MetatableGetter>();
+	final List<StackTraceElement> stackTrace = new ArrayList<StackTraceElement>();
+
+	public final LuanTable global() {
+		return global;
+	}
+
+	public final LuanTable getMetatable(Object obj) {
+		if( obj instanceof LuanTable ) {
+			LuanTable table = (LuanTable)obj;
+			return table.getMetatable();
+		}
+		for( MetatableGetter mg : mtGetters ) {
+			LuanTable table = mg.getMetatable(obj);
+			if( table != null )
+				return table;
+		}
+		return null;
+	}
+
+	public final void addMetatableGetter(MetatableGetter mg) {
+		mtGetters.add(mg);
+	}
+
+	public Object[] call(LuanFunction fn,LuanElement calledFrom,String fnName,Object... args) throws LuanException {
+		stackTrace.add( new StackTraceElement(calledFrom,fnName) );
+		try {
+			return fn.call(this,args);
+		} finally {
+			stackTrace.remove(stackTrace.size()-1);
+		}
+	}
+
+	public final String checkString(LuanElement el,Object obj) throws LuanException {
+		String s = Luan.asString(obj);
+		if( s == null )
+			throw new LuanException( this, el, "attempt to use a " + Luan.type(obj) + " as a string" );
+		return s;
+	}
+
+	public final Number checkNumber(LuanElement el,Object obj) throws LuanException {
+		Number n = Luan.toNumber(obj);
+		if( n == null )
+			throw new LuanException( this, el, "attempt to perform arithmetic on a " + Luan.type(obj) + " value" );
+		return n;
+	}
+
+	public final LuanFunction checkFunction(LuanElement el,Object obj) throws LuanException {
+		if( obj instanceof LuanFunction )
+			return (LuanFunction)obj;
+		throw new LuanException( this, el, "attempt to call a " + Luan.type(obj) + " value" );
+	}
+
+	public final String toString(LuanElement el,Object obj) throws LuanException {
+		LuanFunction fn = getHandlerFunction(el,"__tostring",obj);
+		if( fn != null )
+			return checkString( el, Luan.first( call(fn,el,"__tostring",obj) ) );
+		if( obj == null )
+			return "nil";
+		if( obj instanceof Number )
+			return Luan.toString((Number)obj);
+		if( obj instanceof LuanException ) {
+			LuanException le = (LuanException)obj;
+			return le.getMessage();
+		}
+		return obj.toString();
+	}
+
+	public final LuanFunction getHandlerFunction(LuanElement el,String op,Object obj) throws LuanException {
+		Object f = getHandler(op,obj);
+		if( f == null )
+			return null;
+		return checkFunction(el,f);
+	}
+
+	public final Object getHandler(String op,Object obj) {
+		LuanTable t = getMetatable(obj);
+		return t==null ? null : t.get(op);
+	}
+
+
+	public final LuanFunction getBinHandler(LuanElement el,String op,Object o1,Object o2) throws LuanException {
+		LuanFunction f1 = getHandlerFunction(el,op,o1);
+		if( f1 != null )
+			return f1;
+		return getHandlerFunction(el,op,o2);
+	}
+
+	public final boolean isLessThan(LuanElement el,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(el,"__lt",o1,o2);
+		if( fn != null )
+			return Luan.toBoolean( Luan.first(call(fn,el,"__lt",o1,o2)) );
+		throw new LuanException( this, el, "attempt to compare " + Luan.type(o1) + " with " + Luan.type(o2) );
+	}
+}