Maintainer  Ivan.Miljenovic@gmail.com 

Safe Haskell  None 
It is sometimes useful to be able to manipulate a Dot graph as an
actual graph. This representation lets you do so, using an
inductive approach based upon that from FGL (note that DotGraph
is not an instance of the FGL classes due to having the wrong
kind). Note, however, that the API is not as complete as proper
graph implementations.
For purposes of manipulation, all edges are found in the root graph
and not in a cluster; as such, having EdgeAttrs
in a cluster's
GlobalAttributes
is redundant.
Printing is achieved via Data.GraphViz.Types.Canonical (using
toCanonical
) and parsing via Data.GraphViz.Types.Generalised
(so any piece of Dot code can be parsed in).
This representation doesn't allow noncluster subgraphs. Also, all
clusters must have a unique identifier. For those functions (with
the exception of DotRepr
methods) that take or return a "Maybe
GraphID
", a value of "Nothing
" refers to the root graph; "Just
clust
" refers to the cluster with the identifier "clust
".
You would not typically explicitly create these values, instead
converting existing Dot graphs (via fromDotRepr
). However, one
way of constructing the sample graph would be:
setID (Str "G") . setStrictness False . setIsDirected True . setClusterAttributes (Int 0) [GraphAttrs [style filled, color LightGray, textLabel "process #1"], NodeAttrs [style filled, color White]] . setClusterAttributes (Int 1) [GraphAttrs [textLabel "process #2", color Blue], NodeAttrs [style filled]] $ composeList [ Cntxt "a0" (Just $ Int 0) [] [("a3",[]),("start",[])] [("a1",[])] , Cntxt "a1" (Just $ Int 0) [] [] [("a2",[]),("b3",[])] , Cntxt "a2" (Just $ Int 0) [] [] [("a3",[])] , Cntxt "a3" (Just $ Int 0) [] [("b2",[])] [("end",[])] , Cntxt "b0" (Just $ Int 1) [] [("start",[])] [("b1",[])] , Cntxt "b1" (Just $ Int 1) [] [] [("b2",[])] , Cntxt "b2" (Just $ Int 1) [] [] [("b3",[])] , Cntxt "b3" (Just $ Int 1) [] [] [("end",[])] , Cntxt "end" Nothing [shape MSquare] [] [] , Cntxt "start" Nothing [shape MDiamond] [] []]
 data DotGraph n
 data GraphID
 data Context n = Cntxt {
 node :: !n
 inCluster :: !(Maybe GraphID)
 attributes :: !Attributes
 predecessors :: ![(n, Attributes)]
 successors :: ![(n, Attributes)]
 toCanonical :: Ord n => DotGraph n > DotGraph n
 unsafeFromCanonical :: Ord n => DotGraph n > DotGraph n
 fromDotRepr :: DotRepr dg n => dg n > DotGraph n
 isEmpty :: DotGraph n > Bool
 hasClusters :: DotGraph n > Bool
 isEmptyGraph :: DotGraph n > Bool
 graphAttributes :: DotGraph n > [GlobalAttributes]
 parentOf :: DotGraph n > GraphID > Maybe GraphID
 clusterAttributes :: DotGraph n > GraphID > [GlobalAttributes]
 foundInCluster :: Ord n => DotGraph n > n > Maybe GraphID
 attributesOf :: Ord n => DotGraph n > n > Attributes
 predecessorsOf :: Ord n => DotGraph n > n > [DotEdge n]
 successorsOf :: Ord n => DotGraph n > n > [DotEdge n]
 adjacentTo :: Ord n => DotGraph n > n > [DotEdge n]
 adjacent :: Context n > [DotEdge n]
 mkGraph :: Ord n => [DotNode n] > [DotEdge n] > DotGraph n
 emptyGraph :: DotGraph n
 (&) :: Ord n => Context n > DotGraph n > DotGraph n
 composeList :: Ord n => [Context n] > DotGraph n
 addNode :: Ord n => n > Maybe GraphID > Attributes > DotGraph n > DotGraph n
 data DotNode n = DotNode {
 nodeID :: n
 nodeAttributes :: Attributes
 addDotNode :: Ord n => DotNode n > DotGraph n > DotGraph n
 addEdge :: Ord n => n > n > Attributes > DotGraph n > DotGraph n
 data DotEdge n = DotEdge {
 fromNode :: n
 toNode :: n
 edgeAttributes :: Attributes
 addDotEdge :: Ord n => DotEdge n > DotGraph n > DotGraph n
 addCluster :: GraphID > Maybe GraphID > [GlobalAttributes] > DotGraph n > DotGraph n
 setClusterParent :: GraphID > Maybe GraphID > DotGraph n > DotGraph n
 setClusterAttributes :: GraphID > [GlobalAttributes] > DotGraph n > DotGraph n
 decompose :: Ord n => n > DotGraph n > Maybe (Context n, DotGraph n)
 decomposeAny :: Ord n => DotGraph n > Maybe (Context n, DotGraph n)
 decomposeList :: Ord n => DotGraph n > [Context n]
 deleteNode :: Ord n => n > DotGraph n > DotGraph n
 deleteAllEdges :: Ord n => n > n > DotGraph n > DotGraph n
 deleteEdge :: Ord n => n > n > Attributes > DotGraph n > DotGraph n
 deleteDotEdge :: Ord n => DotEdge n > DotGraph n > DotGraph n
 deleteCluster :: Ord n => GraphID > DotGraph n > DotGraph n
 removeEmptyClusters :: Ord n => DotGraph n > DotGraph n
Documentation
A Dot graph that allows graph operations on it.
(Ord n, PrintDot n, ParseDot n) => PPDotRepr DotGraph n  
(Ord n, ParseDot n) => ParseDotRepr DotGraph n  
(Ord n, PrintDot n) => PrintDotRepr DotGraph n  
Ord n => DotRepr DotGraph n  
Ord n => FromGeneralisedDot DotGraph n  
Eq n => Eq (DotGraph n)  
Ord n => Ord (DotGraph n)  
(Ord n, Read n) => Read (DotGraph n)  If the graph is the output from 
(Ord n, Show n) => Show (DotGraph n)  It should be safe to substitute 
(Ord n, ParseDot n) => ParseDot (DotGraph n)  Uses the ParseDot instance for generalised 
(Ord n, PrintDot n) => PrintDot (DotGraph n)  Uses the PrintDot instance for canonical 
The decomposition of a node from a dot graph. Any loops should
be found in successors
rather than predecessors
. Note also
that these are created/consumed as if for directed graphs.
Cntxt  

Conversions
toCanonical :: Ord n => DotGraph n > DotGraph nSource
Convert this DotGraph into canonical form. All edges are found in the outer graph rather than in clusters.
unsafeFromCanonical :: Ord n => DotGraph n > DotGraph nSource
Convert a canonical Dot graph to a graphbased one. This assumes
that the canonical graph is the same format as returned by
toCanonical
. The "unsafeness" is that:
 All clusters must have a unique identifier (
unAnonymise
can be used to make sure all clusters have an identifier, but it doesn't ensure uniqueness).  All nodes are assumed to be explicitly listed precisely once.
 Only edges found in the root graph are considered.
If this isn't the case, use fromCanonical
instead.
The graphToDot
function from Data.GraphViz produces output
suitable for this function (assuming all clusters are provided
with a unique identifier); graphElemsToDot
is suitable if all
nodes are specified in the input list (rather than just the
edges).
fromDotRepr :: DotRepr dg n => dg n > DotGraph nSource
Convert any existing DotRepr instance to a DotGraph
.
Graph information
hasClusters :: DotGraph n > BoolSource
Does this graph have any clusters?
isEmptyGraph :: DotGraph n > BoolSource
Determine if this graph has nodes or clusters.
graphAttributes :: DotGraph n > [GlobalAttributes]Source
parentOf :: DotGraph n > GraphID > Maybe GraphIDSource
Which cluster (or the root graph) is this cluster in?
clusterAttributes :: DotGraph n > GraphID > [GlobalAttributes]Source
foundInCluster :: Ord n => DotGraph n > n > Maybe GraphIDSource
Return the ID for the cluster the node is in.
attributesOf :: Ord n => DotGraph n > n > AttributesSource
Return the attributes for the node.
predecessorsOf :: Ord n => DotGraph n > n > [DotEdge n]Source
Predecessor edges for the specified node. For undirected graphs
equivalent to adjacentTo
.
successorsOf :: Ord n => DotGraph n > n > [DotEdge n]Source
Successor edges for the specified node. For undirected graphs
equivalent to adjacentTo
.
adjacentTo :: Ord n => DotGraph n > n > [DotEdge n]Source
All edges involving this node.
Graph construction
emptyGraph :: DotGraph nSource
(&) :: Ord n => Context n > DotGraph n > DotGraph nSource
Merge the Context
into the graph. Assumes that the specified
node is not in the graph but that all endpoints in the
successors
and predecessors
(with the exception of loops)
are. If the cluster is not present in the graph, then it will be
added with no attributes with a parent of the root graph.
Note that &
and
are not quite inverses, as this
function will add in the cluster if it does not yet exist in the
graph, but decompose
decompose
will not delete it.
composeList :: Ord n => [Context n] > DotGraph nSource
Recursively merge the list of contexts.
composeList = foldr (&) emptyGraph
:: Ord n  
=> n  
> Maybe GraphID  The cluster the node can be found in
( 
> Attributes  
> DotGraph n  
> DotGraph n 
Add a node to the current graph. Throws an error if the node already exists in the graph.
If the specified cluster does not yet exist in the graph, then it will be added (as a subgraph of the overall graph and no attributes).
A node in DotGraph
.
DotNode  

addDotNode :: Ord n => DotNode n > DotGraph n > DotGraph nSource
A variant of addNode
that takes in a DotNode (not in a
cluster).
addEdge :: Ord n => n > n > Attributes > DotGraph n > DotGraph nSource
Add the specified edge to the graph; assumes both node values are already present in the graph. If the graph is undirected then the order of nodes doesn't matter.
An edge in DotGraph
.
DotEdge  

:: GraphID  The identifier for this cluster. 
> Maybe GraphID  The parent of this cluster
( 
> [GlobalAttributes]  
> DotGraph n  
> DotGraph n 
Add a new cluster to the graph; throws an error if the cluster already exists. Assumes that it doesn't match the identifier of the overall graph. If the parent cluster doesn't already exist in the graph then it will be added.
setClusterParent :: GraphID > Maybe GraphID > DotGraph n > DotGraph nSource
Specify the parent of the cluster; adds both in if not already present.
setClusterAttributes :: GraphID > [GlobalAttributes] > DotGraph n > DotGraph nSource
Specify the attributes of the cluster; adds it if not already present.
Graph deconstruction
decompose :: Ord n => n > DotGraph n > Maybe (Context n, DotGraph n)Source
A partial inverse of
, in that if a node exists in a graph
then it will be decomposed, but will not remove the cluster that
it was in even if it was the only node in that cluster.
&
decomposeAny :: Ord n => DotGraph n > Maybe (Context n, DotGraph n)Source
As with decompose
, but do not specify which node to
decompose.
decomposeList :: Ord n => DotGraph n > [Context n]Source
Recursively decompose the Dot graph into a list of contexts such
that if (c:cs) = decomposeList dg
, then dg = c &
.
composeList
cs
Note that all global attributes are lost, so this is not suitable for representing a Dot graph on its own.
deleteNode :: Ord n => n > DotGraph n > DotGraph nSource
Delete the specified node from the graph; returns the original graph if that node isn't present.
deleteAllEdges :: Ord n => n > n > DotGraph n > DotGraph nSource
Delete all edges between the two nodes; returns the original graph if there are no edges.
deleteEdge :: Ord n => n > n > Attributes > DotGraph n > DotGraph nSource
Deletes the specified edge from the DotGraph (note: for unordered graphs both orientations are considered).
deleteDotEdge :: Ord n => DotEdge n > DotGraph n > DotGraph nSource
As with deleteEdge
but takes a DotEdge
rather than individual
values.
deleteCluster :: Ord n => GraphID > DotGraph n > DotGraph nSource
Delete the specified cluster, and makes any clusters or nodes within it be in its root cluster (or the overall graph if required).
removeEmptyClusters :: Ord n => DotGraph n > DotGraph nSource
Remove clusters with no subclusters and no nodes within them.