lojix/wam_prolog/src/main/com/thesett/aima/logic/fol/wam/machine/WAMResolvingJavaMachine.java
private boolean callInternal(int function, int arity, int numPerms)
    {
        switch (function)
        {
        case CALL_1_ID:
            return internalCall_1(numPerms);

        case EXECUTE_1_ID:
            return internalExecute_1();

        default:
            throw new IllegalStateException("Unknown internal function id: " + function);
        }
    }
private boolean callInternal(int function, int arity, int numPerms)
    {
        switch (function)
        {
        case CALL_1_ID:
            return internalCall_1(numPerms);

        case EXECUTE_1_ID:
            return internalExecute_1();

        default:
            throw new IllegalStateException("Unknown internal function id: " + function);
        }
    }
Invokes an internal function.

@param  function The id of the internal function to call.
@param  arity    The arity of the function to call.
@param  numPerms The number of permanent variables remaining in the environment.

@return <tt>true</tt> if the call succeeded, and <tt>false</tt> if it failed.