example.dot

strict digraph G {
    // nodes creation, shape and style defined here
    bgcolor=invis
    {
      node [style="rounded, filled" shape=box]
      class, FILE, PIPE, PIPEFILE
    }
    {
      node [style=filled margin=0 width=1 height=0.46 shape=polygon fixedsize=true skew=0.4]
      format, file_format, pipe_format, pipefile_format
    }
    {
      node [shape=none]
      patterns, file_patterns, pipe_patterns, pipefile_patterns
    }
    {
      node [style="dashed, filled" shape=box]
      example, file_example, pipe_example, pipefile_example
    }
    // connections, labels and color related updates by higher level groups
    subgraph legend {
        edge[style=invis]  // connect with invisible edges to emulate a legend
        class, format, example, patterns [color=gray40 fillcolor=gray95]
        patterns [label="field=pattern" fontcolor=gray22]
        class -> format -> patterns  -> example
    }

    FILE, file_format, file_example [color=lightgoldenrod3 fillcolor=lemonchiffon1]
    file_format [label=".{suffix}"]
    file_example [label=".ext"]
    // escape the inverse slash so generated image displays one
    file_patterns [label="suffix = \\w+" fontcolor=lightgoldenrod4]

    PIPE, pipe_format, pipe_example [color=lightskyblue4 fillcolor=lightblue]
    pipe_format [label=".{pipe}"]
    pipe_example [label=".1
    .1.out
    .1.out.101"]
    pipe_patterns [label="version = \\d+
    output = \\w+?
    frame = \\d+?"]

    PIPEFILE, pipefile_format, pipefile_example [color=mediumorchid4 fillcolor=plum2]
    pipefile_format [skew=0.15 width=2 label="{base}.{pipe}.{suffix}"]
    pipefile_example [label="wip_data.7.ext
    pipe_data.7.out.ext
    framed_data.7.out.101.ext"]
    pipefile_patterns [label="base = \\w+" fontcolor=mediumorchid4]

    edge [color=gray36 arrowhead="vee"]
    PIPE -> pipe_format -> pipe_patterns -> pipe_example
    FILE -> file_format -> file_patterns -> file_example
    PIPEFILE -> pipefile_format -> pipefile_patterns -> pipefile_example
    {PIPE, FILE} -> PIPEFILE
}