@@ -0,0 +1,674 @@
+package org.nwapw.abacus.number;%0A%0Aimport java.util.HashMap;%0A%0Apublic abstract class externalFunction %7B%0A%0A    private HashMap%3CString, Function%3E functions;%0A%0A    public externalFunction()%7B%0A        functions=new HashMap%3C%3E();%0A    %7D%0A%0A    public boolean hasFunction(Function x)%7B%0A        return functions.containsKey(x);%0A    %7D%0A    public Function getFunction(String x)%7B%0A        return functions.get(x);%0A    %7D%0A    public boolean registerFunction(String x, Function y)%7B%0A        if(!functions.containsKey(x))%0A            return functions.put(x,y)==null;%0A        return false;%0A    %7D%0A    public Function functionFor(String x)%7B%0A        return null;%0A    %7D%0A    public abstract void load();%0A%7D%0A

Add an abstact class for external functions