Copyright | (c) Brett Wines 2014 |
---|---|

License | BSD-style |

Maintainer | bgwines@cs.stanford.edu |

Stability | experimental |

Portability | portable |

Safe Haskell | Safe-Inferred |

Language | Haskell98 |

A typeclass with default implementation for graphing trees with Haskell GraphViz.

# Documentation

class Zoldable g => Graphable g where Source

A typeclass for algebraic data types that are able to be graphed. For these descriptions, assume the following example data type:

data Tree a = Empty | Leaf a | Node a (Tree a) (Tree a)

See the supporting file `dot.hs`

for an example of how to graph your data type.

Gets the value contained in a node. For example,

value (Empty) = error "Empty nodes don't contain values." value (Leaf x) = x value (Node x _ _) = x

get_children :: g a -> [g a] Source

Gets the children of the current node. For example,

get_children (Empty) = error "Empty nodes don't have children." get_children (Leaf _) = [] get_children (Node _ l r) = [l, r]

is_empty :: g a -> Bool Source

Returns whether a node is empty. Sometimes, when declaring algebraic data types, it is desirable to have an Empty value constructor. If your data type does not have an Empty value constructor, just always return `False`

.

is_empty (Empty) = True is_empty _ = False

graph :: forall a. (Show a, Ord a) => g a -> Graph Source

Returns a `Graph`

for the given `Graphable`

type. You shouldn't need to override this implementation.