--- a/src/luan/modules/Utils.java	Thu Sep 05 01:29:57 2019 -0600
+++ b/src/luan/modules/Utils.java	Fri Sep 06 00:19:47 2019 -0600
@@ -104,6 +104,13 @@
 		return (String)val;
 	}
 
+	public static String removeRequiredString(Map map,String key) throws LuanException {
+		String s = removeString(map,key);
+		if( s==null )
+			throw new LuanException( "parameter '"+key+"' is required" );
+		return s;
+	}
+
 	public static Number removeNumber(Map map,String key) throws LuanException {
 		Object val = map.remove(key);
 		if( val!=null && !(val instanceof Number) )
@@ -111,7 +118,7 @@
 		return (Number)val;
 	}
 
-	public static Integer removeInt(Map map,String key) throws LuanException {
+	public static Integer removeInteger(Map map,String key) throws LuanException {
 		Object val = map.remove(key);
 		if( val==null )
 			return null;
@@ -137,6 +144,20 @@
 		return (Boolean)val;
 	}
 
+	public static LuanFunction removeFunction(Map map,String key) throws LuanException {
+		Object val = map.remove(key);
+		if( val!=null && !(val instanceof LuanFunction) )
+			throw new LuanException( "parameter '"+key+"' must be a function but is a "+Luan.type(val) );
+		return (LuanFunction)val;
+	}
+
+	public static LuanFunction removeRequiredFunction(Map map,String key) throws LuanException {
+		LuanFunction fn = removeFunction(map,key);
+		if( fn==null )
+			throw new LuanException( "parameter '"+key+"' is required" );
+		return fn;
+	}
+
 	public static void checkEmpty(Map map) throws LuanException {
 		if( !map.isEmpty() )
 			throw new LuanException( "unrecognized options: "+map );