{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-} {- | Module : Data.GraphViz.Types Description : Haskell representation of Dot graphs. Copyright : (c) Ivan Lazar Miljenovic License : 3-Clause BSD-style Maintainer : Ivan.Miljenovic@gmail.com Four different representations of Dot graphs are available, all of which are based loosely upon the specifications at: <http://graphviz.org/doc/info/lang.html>. The 'DotRepr' class provides a common interface for them (the 'PrintDotRepr', 'ParseDotRepr' and 'PPDotRepr' classes are used until class aliases are implemented). Every representation takes in a type parameter: this indicates the node type (e.g. @DotGraph Int@ is a Dot graph with integer nodes). Sum types are allowed, though care must be taken when specifying their 'ParseDot' instances if there is the possibility of overlapping definitions. The 'GraphID' type is an existing sum type that allows textual and numeric values. If you require using more than one Dot representation, you will most likely need to import at least one of them qualified, as they typically all use the same names. As a comparison, all four representations provide how you would define the following Dot graph (or at least one isomorphic to it) (the original of which can be found at <http://graphviz.org/content/cluster>). Note that in all the examples, they are not necessarily done the best way (variables rather than repeated constants, etc.); they are just there to provide a comparison on the structure of each representation. > digraph G { > > subgraph cluster_0 { > style=filled; > color=lightgrey; > node [style=filled,color=white]; > a0 -> a1 -> a2 -> a3; > label = "process #1"; > } > > subgraph cluster_1 { > node [style=filled]; > b0 -> b1 -> b2 -> b3; > label = "process #2"; > color=blue > } > start -> a0; > start -> b0; > a1 -> b3; > b2 -> a3; > a3 -> a0; > a3 -> end; > b3 -> end; > > start [shape=Mdiamond]; > end [shape=Msquare]; > } Each representation is suited for different things: ["Data.GraphViz.Types.Canonical"] is ideal for converting other graph-like data structures into Dot graphs (the "Data.GraphViz" module provides some functions for this). It is a structured representation of Dot code. ["Data.GraphViz.Types.Generalised"] matches the actual structure of Dot code. As such, it is suited for parsing in existing Dot code. ["Data.GraphViz.Types.Graph"] provides graph operations for manipulating Dot graphs; this is suited when you want to edit existing Dot code. It uses generalised Dot graphs for parsing and canonical Dot graphs for printing. ["Data.GraphViz.Types.Monadic"] is a much easier representation to use when defining relatively static Dot graphs in Haskell code, and looks vaguely like actual Dot code if you squint a bit. Please also read the limitations section at the end for advice on how to properly use these Dot representations. -} module Data.GraphViz.Types ( DotRepr(..) , PrintDotRepr , ParseDotRepr , PPDotRepr -- * Common sub-types , GraphID(..) , GlobalAttributes(..) , DotNode(..) , DotEdge(..) -- * Helper types for looking up information within a @DotRepr@. , ClusterLookup , NodeLookup , Path -- * Obtaining the @DotNode@s and @DotEdges@. , graphNodes , graphEdges -- * Printing and parsing a @DotRepr@. , printDotGraph , parseDotGraph -- * Limitations and documentation -- $limitations ) where import Data.GraphViz.Types.Canonical( DotGraph(..), DotStatements(..) , DotSubGraph(..)) import Data.GraphViz.Types.Common( GraphID(..), GlobalAttributes(..) , DotNode(..), DotEdge(..), numericValue) import Data.GraphViz.Types.State import Data.GraphViz.Util(bool) import Data.GraphViz.Parsing(ParseDot, parseIt) import Data.GraphViz.PreProcessing(preProcess) import Data.GraphViz.Printing(PrintDot, printIt) import Data.Text.Lazy(Text) import Control.Monad.Trans.State(get, put, modify, execState, evalState) -- ----------------------------------------------------------------------------- -- | This class is used to provide a common interface to different -- ways of representing a graph in /Dot/ form. -- -- You will most probably /not/ need to create your own instances of -- this class. -- -- The type variable represents the current node type of the Dot -- graph, and the 'Ord' restriction is there because in practice -- most implementations of some of these methods require it. class (Ord n) => DotRepr dg n where -- | Convert from a graph in canonical form. This is especially -- useful when using the functions from "Data.GraphViz.Algorithms". fromCanonical :: DotGraph n -> dg n -- | Return the ID of the graph. getID :: dg n -> Maybe GraphID -- | Set the ID of the graph. setID :: GraphID -> dg n -> dg n -- | Is this graph directed? graphIsDirected :: dg n -> Bool -- | Set whether a graph is directed or not. setIsDirected :: Bool -> dg n -> dg n -- | Is this graph strict? Strict graphs disallow multiple edges. graphIsStrict :: dg n -> Bool -- | A strict graph disallows multiple edges. setStrictness :: Bool -> dg n -> dg n -- | Change the node values. This function is assumed to be -- /injective/, otherwise the resulting graph will not be -- identical to the original (modulo labels). mapDotGraph :: (Ord n', DotRepr dg n') => (n -> n') -> dg n -> dg n' -- | Return information on all the clusters contained within this -- 'DotRepr', as well as the top-level 'GraphAttrs' for the -- overall graph. graphStructureInformation :: dg n -> (GlobalAttributes, ClusterLookup) -- | Return information on the 'DotNode's contained within this -- 'DotRepr'. The 'Bool' parameter indicates if applicable -- 'NodeAttrs' should be included. nodeInformation :: Bool -> dg n -> NodeLookup n -- | Return information on the 'DotEdge's contained within this -- 'DotRepr'. The 'Bool' parameter indicates if applicable -- 'EdgeAttrs' should be included. edgeInformation :: Bool -> dg n -> [DotEdge n] -- | Give any anonymous sub-graphs or clusters a unique identifier -- (i.e. there will be no 'Nothing' key in the 'ClusterLookup' -- from 'graphStructureInformation'). unAnonymise :: dg n -> dg n -- | This class exists just to make type signatures nicer; all -- instances of 'DotRepr' should also be an instance of -- 'PrintDotRepr'. class (DotRepr dg n, PrintDot (dg n)) => PrintDotRepr dg n -- | This class exists just to make type signatures nicer; all -- instances of 'DotRepr' should also be an instance of -- 'ParseDotRepr'. class (DotRepr dg n, ParseDot (dg n)) => ParseDotRepr dg n -- | This class exists just to make type signatures nicer; all -- instances of 'DotRepr' should also be an instance of -- 'PPDotRepr'. class (PrintDotRepr dg n, ParseDotRepr dg n) => PPDotRepr dg n -- | Returns all resultant 'DotNode's in the 'DotRepr' (not including -- 'NodeAttr's). graphNodes :: (DotRepr dg n) => dg n -> [DotNode n] graphNodes = toDotNodes . nodeInformation False -- | Returns all resultant 'DotEdge's in the 'DotRepr' (not including -- 'EdgeAttr's). graphEdges :: (DotRepr dg n) => dg n -> [DotEdge n] graphEdges = edgeInformation False -- | The actual /Dot/ code for an instance of 'DotRepr'. Note that it -- is expected that @'parseDotGraph' . 'printDotGraph' == 'id'@ -- (this might not be true the other way around due to un-parseable -- components). printDotGraph :: (PrintDotRepr dg n) => dg n -> Text printDotGraph = printIt -- | Parse a limited subset of the Dot language to form an instance of -- 'DotRepr'. Each instance may have its own limitations on what -- may or may not be parseable Dot code. -- -- Also removes any comments, etc. before parsing. parseDotGraph :: (ParseDotRepr dg n) => Text -> dg n parseDotGraph = fst . parseIt . preProcess -- ----------------------------------------------------------------------------- -- Instance for Canonical graphs, to avoid cyclic modules. instance (Ord n) => DotRepr DotGraph n where fromCanonical = id getID = graphID setID i g = g { graphID = Just i } graphIsDirected = directedGraph setIsDirected d g = g { directedGraph = d } graphIsStrict = strictGraph setStrictness s g = g { strictGraph = s } mapDotGraph = fmap graphStructureInformation = getGraphInfo . statementStructure . graphStatements nodeInformation wGlobal = getNodeLookup wGlobal . statementNodes . graphStatements edgeInformation wGlobal = getDotEdges wGlobal . statementEdges . graphStatements unAnonymise = renumber instance (Ord n, PrintDot n) => PrintDotRepr DotGraph n instance (Ord n, ParseDot n) => ParseDotRepr DotGraph n instance (Ord n, PrintDot n, ParseDot n) => PPDotRepr DotGraph n statementStructure :: DotStatements n -> GraphState () statementStructure stmts = do mapM_ addGraphGlobals $ attrStmts stmts mapM_ (withSubGraphID addSubGraph statementStructure) $ subGraphs stmts statementNodes :: (Ord n) => DotStatements n -> NodeState n () statementNodes stmts = do mapM_ addNodeGlobals $ attrStmts stmts mapM_ (withSubGraphID recursiveCall statementNodes) $ subGraphs stmts mapM_ addNode $ nodeStmts stmts mapM_ addEdgeNodes $ edgeStmts stmts statementEdges :: DotStatements n -> EdgeState n () statementEdges stmts = do mapM_ addEdgeGlobals $ attrStmts stmts mapM_ (withSubGraphID recursiveCall statementEdges) $ subGraphs stmts mapM_ addEdge $ edgeStmts stmts withSubGraphID :: (Maybe (Maybe GraphID) -> b -> a) -> (DotStatements n -> b) -> DotSubGraph n -> a withSubGraphID f g sg = f mid . g $ subGraphStmts sg where mid = bool Nothing (Just $ subGraphID sg) $ isCluster sg renumber :: DotGraph n -> DotGraph n renumber dg = dg { graphStatements = newStmts } where startN = succ $ maxSGInt dg newStmts = evalState (stRe $ graphStatements dg) startN stRe st = do sgs' <- mapM sgRe $ subGraphs st return $ st { subGraphs = sgs' } sgRe sg = do sgid' <- case subGraphID sg of Nothing -> do n <- get put $ succ n return . Just $ Int n sgid -> return sgid stmts' <- stRe $ subGraphStmts sg return $ sg { subGraphID = sgid' , subGraphStmts = stmts' } maxSGInt :: DotGraph n -> Int maxSGInt dg = execState (stInt $ graphStatements dg) . flip check 0 $ graphID dg where check = maybe id max . (numericValue =<<) stInt = mapM_ sgInt . subGraphs sgInt sg = do modify (check $ subGraphID sg) stInt $ subGraphStmts sg -- ----------------------------------------------------------------------------- {- $limitations Printing of /Dot/ code is done as strictly as possible, whilst parsing is as permissive as possible. For example, if the types allow it then @\"2\"@ will be parsed as an 'Int' value. Note that quoting and escaping of textual values is done automagically. A summary of known limitations\/differences: * When creating 'GraphID' values for graphs and sub-graphs, you should ensure that none of them have the same printed value as one of the node identifiers values to avoid any possible problems. * If you want any 'GlobalAttributes' in a sub-graph and want them to only apply to that sub-graph, then you must ensure it does indeed have a valid 'GraphID'. * All sub-graphs which represent clusters should have unique identifiers (well, only if you want them to be generated sensibly). * If eventually outputting to a format such as SVG, then you should make sure to specify an identifier for the overall graph, as that is used as the title of the resulting image. * Whilst the graphs, etc. are polymorphic in their node type, you should ensure that you use a relatively simple node type (that is, it only covers a single line, etc.). * Also, whilst Graphviz allows you to mix the types used for nodes, this library requires\/assumes that they are all the same type (but you /can/ use a sum-type). * 'DotEdge' defines an edge @(a, b)@ (with an edge going from @a@ to @b@); in /Dot/ parlance the edge has a head at @a@ and a tail at @b@. Care must be taken when using the related @Head*@ and @Tail*@ 'Attribute's. See the differences section in "Data.GraphViz.Attributes" for more information. * It is common to see multiple edges defined on the one line in Dot (e.g. @n1 -> n2 -> n3@ means to create a directed edge from @n1@ to @n2@ and from @n2@ to @n3@). These types of edge definitions are parseable; however, they are converted to singleton edges. * It is not yet possible to create or parse edges with subgraphs\/clusters as one of the end points. * The parser will strip out comments and pre-processor lines, join together multiline statements and concatenate split strings together. However, pre-processing within HTML-like labels is currently not supported. * Graphviz allows a node to be \"defined\" twice (e.g. the actual node definition, and then in a subgraph with extra global attributes applied to it). This actually represents the same node, but when parsing they will be considered as separate 'DotNode's (such that 'graphNodes' will return both \"definitions\"). @canonicalise@ from "Data.GraphViz.Algorithms" can be used to fix this. See "Data.GraphViz.Attributes" for more limitations. -}