code: private void assertApplicable( FunctionInputDef inputDef, VarNamePattern varNamePattern) throws IllegalArgumentException
      {
      if( !varNamePattern.isApplicable( inputDef))
        {
        throw new IllegalArgumentException( "Can't find variable matching pattern=" + varNamePattern);
        }
      }
docs: Throws an exception if the given variable pattern is not applicable to the given input definition.