Copyright | (c) 2003 Graham Klyne 2009 Vasili I Galchin 2011 2012 2016 Douglas Burke |
---|---|

License | GPL V2 |

Maintainer | Douglas Burke |

Stability | experimental |

Portability | CPP, DeriveFunctor, DeriveFoldable, DeriveTraversable, MultiParamTypeClasses |

Safe Haskell | Safe |

Language | Haskell98 |

This module defines a Labelled Directed Graph and Label classes, and the Arc datatype.

- class LDGraph lg lb where
- class (Ord lb, Show lb) => Label lb where
- data Arc lb = Arc {}
- type ArcSet lb = Set (Arc lb)
- type Selector lb = Arc lb -> Bool
- arc :: lb -> lb -> lb -> Arc lb
- arcToTriple :: Arc lb -> (lb, lb, lb)
- arcFromTriple :: (lb, lb, lb) -> Arc lb
- hasLabel :: Eq lb => lb -> Arc lb -> Bool
- arcLabels :: Arc lb -> [lb]
- getComponents :: Ord b => (a -> [b]) -> Set a -> Set b

# Documentation

class LDGraph lg lb where Source #

Labelled Directed Graph class.

Minimum required implementation:
`emptyGraph`

, `setArcs`

, and `getArcs`

.

emptyGraph :: lg lb Source #

Create the empty graph.

setArcs :: lg lb -> ArcSet lb -> lg lb Source #

Replace the existing arcs in the graph.

getArcs :: lg lb -> ArcSet lb Source #

Extract all the arcs from a graph

extract :: Ord lb => Selector lb -> lg lb -> lg lb Source #

Extract those arcs that match the given `Selector`

.

addGraphs :: Ord lb => lg lb -> lg lb -> lg lb Source #

Add the two graphs

delete :: Ord lb => lg lb -> lg lb -> lg lb Source #

Remove those arcs in the first graph from the second graph

labels :: Ord lb => lg lb -> Set lb Source #

Enumerate the distinct labels contained in a graph;
that is, any label that appears in the subject,
predicate or object position of an `Arc`

.

nodes :: Ord lb => lg lb -> Set lb Source #

Enumerate the distinct nodes contained in a graph;
that is, any label that appears in the subject
or object position of an `Arc`

.

update :: (ArcSet lb -> ArcSet lb) -> lg lb -> lg lb Source #

Update the arcs in a graph using a supplied function.

class (Ord lb, Show lb) => Label lb where Source #

Label class.

A label may have a fixed binding, which means that the label identifies (is) a particular graph node, and different such labels are always distinct nodes. Alternatively, a label may be unbound (variable), which means that it is a placeholder for an unknown node label. Unbound node labels are used as graph-local identifiers for indicating when the same node appears in several arcs.

For the purposes of graph-isomorphism testing, fixed labels are matched when they are the same. Variable labels may be matched with any other variable label. Our definition of isomorphism (for RDF graphs) does not match variable labels with fixed labels.

labelIsVar :: lb -> Bool Source #

Does this node have a variable binding?

labelHash :: Int -> lb -> Int Source #

Calculate the hash of the label using the supplied seed.

getLocal :: lb -> String Source #

Extract the local id from a variable node.

makeLabel :: String -> lb Source #

Make a label value from a local id.

Arc type.

Prior to `0.7.0.0`

you could also use `asubj`

, `apred`

and `aobj`

to access the elements of the arc.

:: lb | The subject of the arc. |

-> lb | The predicate of the arc. |

-> lb | The object of the arc. |

-> Arc lb |

Create an arc.

arcToTriple :: Arc lb -> (lb, lb, lb) Source #

Convert an Arc into a tuple.

arcFromTriple :: (lb, lb, lb) -> Arc lb Source #

Create an Arc from a tuple.