{inputs}-->(program)-->{outputs}

##</code><code>##

    {filename}
      |
      +-->(file reader)
            |
            +-->{HTML template}
                      |
    {output message}--+-->(formatter)->{program output}

##</code><code>##

    {filename} + {hardcoded error template}
      |
      +-->(file reader)
            |
            +-->{HTML template}
                      |
    {output message}--+-->(formatter)->{program output}

##</code><code>##

    {inputs}-->(message generator)-->{output message}