opendap/src/main/java/opendap/servers/FunctionLibrary.java
public void add(ServerSideFunction function) {
        if (function instanceof BoolFunction) {
            boolFunctions.put(function.getName(), function);
        }
        if (function instanceof BTFunction) {
            btFunctions.put(function.getName(), function);
        }
    }
public void add(ServerSideFunction function) {
        if (function instanceof BoolFunction) {
            boolFunctions.put(function.getName(), function);
        }
        if (function instanceof BTFunction) {
            btFunctions.put(function.getName(), function);
        }
    }
Adds a function to the library. The function will be inspected
to determine whether it is a boolean or BaseType function.