algebraic-graphs-0.5: A library for algebraic graph construction and transformation

Copyright(c) Andrey Mokhov 2016-2018
LicenseMIT (see the file LICENSE)
Maintainerandrey.mokhov@gmail.com
Stabilityexperimental
Safe HaskellNone
LanguageHaskell2010

Algebra.Graph.Export.Dot

Contents

Description

Alga is a library for algebraic construction and manipulation of graphs in Haskell. See this paper for the motivation behind the library, the underlying theory, and implementation details.

This module defines functions for exporting graphs in the DOT file format.

Synopsis

Graph attributes and style

data Attribute s Source #

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

Constructors

(:=) s s 

data Style a s Source #

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.). Most fields can be empty. 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 example for the function export.

Constructors

Style 

Fields

defaultStyle :: Monoid s => (a -> s) -> Style a s Source #

Default style for exporting graphs. All style settings are empty except for vertexName, which is provided as the only argument.

defaultStyleViaShow :: (Show a, IsString s, Monoid s) => Style a s Source #

Default style for exporting graphs whose vertices are Show-able. All style settings are empty except for vertexName, which is computed from show.

defaultStyleViaShow = defaultStyle (fromString . show)

Export functions

export :: (IsString s, Monoid s, Ord a, ToGraph g, ToVertex g ~ a) => Style a s -> g -> s Source #

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)] }

> 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"
}

exportAsIs :: (IsString s, Monoid s, Ord (ToVertex g), ToGraph g, ToVertex g ~ s) => g -> s Source #

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"
}

exportViaShow :: (IsString s, Monoid s, Ord (ToVertex g), Show (ToVertex g), ToGraph g) => g -> s Source #

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"
}