An attribute is just a key-value pair, for example "shape" := "box". Attributes are used to specify the style of graph elements during export.

The style of quoting used when exporting attributes; DoubleQuotes is the default.

The record Style a s specifies the style to use when exporting a graph in the DOT format. Here a is the type of the graph vertices, and s is the type of string to represent the resulting DOT document (e.g. String, Text, etc.). The only field that has no obvious default value is vertexName, which holds a function of type a -> s to compute vertex names. See the function export for an example.

Default style for exporting graphs. The vertexName field is provided as the only argument; the other fields are set to trivial defaults.

Default style for exporting graphs with Show-able vertices. The vertexName field is computed using show; the other fields are set to trivial defaults.

defaultStyleViaShow = defaultStyle (fromString . show)

Export a graph with a given style.

For example:

style :: Style Int String
style = Style
    { graphName               = "Example"
    , preamble                = ["  // This is an example", ""]
    , graphAttributes         = ["label" := "Example", "labelloc" := "top"]
    , defaultVertexAttributes = ["shape" := "circle"]
    , defaultEdgeAttributes   = mempty
    , vertexName              = \x   -> "v" ++ show x
    , vertexAttributes        = \x   -> ["color" := "blue"   | odd x      ]
    , edgeAttributes          = \x y -> ["style" := "dashed" | odd (x * y)]
    , attributeQuoting        = DoubleQuotes }

> putStrLn $ export style (1 * 2 + 3 * 4 * 5 :: Graph Int)

digraph Example
{
  // This is an example

  graph [label="Example" labelloc="top"]
  node [shape="circle"]
  "v1" [color="blue"]
  "v2"
  "v3" [color="blue"]
  "v4"
  "v5" [color="blue"]
  "v1" -> "v2"
  "v3" -> "v4"
  "v3" -> "v5" [style="dashed"]
  "v4" -> "v5"
}

Export a graph whose vertices are represented simply by their names.

For example:

> Text.putStrLn $ exportAsIs (circuit ["a", "b", "c"] :: AdjacencyMap Text)

digraph
{
  "a"
  "b"
  "c"
  "a" -> "b"
  "b" -> "c"
  "c" -> "a"
}

Export a graph using the defaultStyleViaShow.

For example:

> putStrLn $ exportViaShow (1 + 2 * (3 + 4) :: Graph Int)

digraph
{
  "1"
  "2"
  "3"
  "4"
  "2" -> "3"
  "2" -> "4"
}