-- |
-- Module: Text.Dot
-- Copyright: Andy Gill
-- License: BSD3
--
-- Maintainer: Andy Gill <andygill@ku.edu>
-- Stability: unstable
-- Portability: portable
--
-- This module provides a simple interface for building .dot graph files, for input into the dot and graphviz tools.
-- It includes a monadic interface for building graphs.
module Text.Dot
(
-- * Dot
Dot -- abstract
-- * Nodes
, node
, NodeId -- abstract
, userNodeId
, userNode
-- * Edges
, edge
-- * Showing a graph
, showDot
-- * Other combinators
, scope
, attribute
, nodeAttributes
, edgeAttributes
, graphAttributes
, share
, same
, cluster
-- * Record specification
, Record -- abstract
, field
, portField
, hcat
, hcat'
, vcat
, vcat'
-- * Record node construction
, record
, record'
, record_
, mrecord
, mrecord'
, mrecord_
) where
import Data.List (intersperse)
import Control.Monad (liftM)
data NodeId = NodeId String
| UserNodeId Int
instance Show NodeId where
show (NodeId str) = str
show (UserNodeId i)
| i < 0 = "u_" ++ show (negate i)
| otherwise = "u" ++ show i
data GraphElement = GraphAttribute String String
| GraphNode NodeId [(String,String)]
| GraphEdge NodeId NodeId [(String,String)]
| Scope [GraphElement]
| SubGraph NodeId [GraphElement]
data Dot a = Dot { unDot :: Int -> ([GraphElement],Int,a) }
instance Monad Dot where
return a = Dot $ \ uq -> ([],uq,a)
m >>= k = Dot $ \ uq -> case unDot m uq of
(g1,uq',r) -> case unDot (k r) uq' of
(g2,uq2,r2) -> (g1 ++ g2,uq2,r2)
-- | 'node' takes a list of attributes, generates a new node, and gives a 'NodeId'.
node :: [(String,String)] -> Dot NodeId
node attrs = Dot $ \ uq -> let nid = NodeId $ "n" ++ show uq
in ( [ GraphNode nid attrs ],succ uq,nid)
-- | 'userNodeId' allows a user to use their own (Int-based) node id's, without needing to remap them.
userNodeId :: Int -> NodeId
userNodeId i = UserNodeId i
-- | 'userNode' takes a NodeId, and adds some attributes to that node.
userNode :: NodeId -> [(String,String)] -> Dot ()
userNode nId attrs = Dot $ \ uq -> ( [GraphNode nId attrs ],uq,())
-- | 'edge' generates an edge between two 'NodeId's, with attributes.
edge :: NodeId -> NodeId -> [(String,String)] -> Dot ()
edge from to attrs = Dot (\ uq -> ( [ GraphEdge from to attrs ],uq,()))
-- | 'scope' groups a subgraph together; in dot these are the subgraphs inside "{" and "}".
scope :: Dot a -> Dot a
scope (Dot fn) = Dot (\ uq -> case fn uq of
( elems,uq',a) -> ([Scope elems],uq',a))
-- | 'share' is when a set of nodes share specific attributes. Usually used for layout tweaking.
share :: [(String,String)] -> [NodeId] -> Dot ()
share attrs nodeids = Dot $ \ uq ->
( [ Scope ( [ GraphAttribute name val | (name,val) <- attrs]
++ [ GraphNode nodeid [] | nodeid <- nodeids ]
)
], uq, ())
-- | 'same' provides a combinator for a common pattern; a set of 'NodeId's with the same rank.
same :: [NodeId] -> Dot ()
same = share [("rank","same")]
-- | 'cluster' builds an explicit, internally named subgraph (called cluster).
cluster :: Dot a -> Dot (NodeId,a)
cluster (Dot fn) = Dot (\ uq ->
let cid = NodeId $ "cluster_" ++ show uq
in case fn (succ uq) of
(elems,uq',a) -> ([SubGraph cid elems],uq',(cid,a)))
-- | 'attribute' gives a attribute to the current scope.
attribute :: (String,String) -> Dot ()
attribute (name,val) = Dot (\ uq -> ( [ GraphAttribute name val ],uq,()))
-- | 'nodeAttributes' sets attributes for all the following nodes in the scope.
nodeAttributes :: [(String,String)] -> Dot ()
nodeAttributes attrs = Dot (\uq -> ([ GraphNode (NodeId "node") attrs],uq,()))
-- | 'edgeAttributes' sets attributes for all the following edges in the scope.
edgeAttributes :: [(String,String)] -> Dot ()
edgeAttributes attrs = Dot (\uq -> ([ GraphNode (NodeId "edge") attrs],uq,()))
-- | 'graphAttributes' sets attributes for current graph.
graphAttributes :: [(String,String)] -> Dot ()
graphAttributes attrs = Dot (\uq -> ([ GraphNode (NodeId "graph") attrs],uq,()))
-- 'showDot' renders a dot graph as a 'String'.
showDot :: Dot a -> String
showDot (Dot dm) = case dm 0 of
(elems,_,_) -> "digraph G {\n" ++ unlines (map showGraphElement elems) ++ "\n}\n"
showGraphElement :: GraphElement -> String
showGraphElement (GraphAttribute name val) = showAttr (name,val) ++ ";"
showGraphElement (GraphNode nid attrs) = show nid ++ showAttrs attrs ++ ";"
showGraphElement (GraphEdge from to attrs) = show from ++ " -> " ++ show to ++ showAttrs attrs ++ ";"
showGraphElement (Scope elems) = "{\n" ++ unlines (map showGraphElement elems) ++ "\n}"
showGraphElement (SubGraph nid elems) = "subgraph " ++ show nid ++ " {\n" ++ unlines (map showGraphElement elems) ++ "\n}"
showAttrs :: [(String, String)] -> String
showAttrs [] = ""
showAttrs xs = "[" ++ showAttrs' xs ++ "]"
where
-- never empty list
showAttrs' [a] = showAttr a
showAttrs' (a:as) = showAttr a ++ "," ++ showAttrs' as
showAttrs' [] = error "showAttrs: the impossible happended"
showAttr :: (String, String) -> String
showAttr (name,val) = name ++ "=\"" ++ concatMap escape val ++ "\""
where escape '\n' = "\\l"
escape '"' = "\\\""
escape c = [c]
------------------------------------------------------------------------------
-- Records
------------------------------------------------------------------------------
-- | Specifies the construction of a record; i.e., mentions all fields possibly
-- together with ports and their horizontal and vertical nesting. (see: record
-- shapes in the DOT documentation.)
data Record a =
Field (Maybe a) String
| HCat [Record a]
| VCat [Record a]
deriving( Eq, Ord, Show )
-- | A simple field of a record.
field :: String -> Record a
field = Field Nothing
-- | A field together with a port which can be used to create direct edges to
-- this field. Note that you can use any type to identify the ports. When
-- creating a record node you will get back an association list between your
-- record identifiers and their concrete node ids.
portField :: a -> String -> Record a
portField port = Field (Just port)
-- | Concatenate records horizontally.
hcat :: [Record a] -> Record a
hcat = HCat
-- | Concatenate a list strings interpreted as simple fields horizontally.
hcat' :: [String] -> Record a
hcat' = hcat . map field
-- | Concatenate records vertically.
vcat :: [Record a] -> Record a
vcat = VCat
-- | Concatenate a list strings interpreted as simple fields vertically.
vcat' :: [String] -> Record a
vcat' = vcat . map field
-- | Render a record in the Dot monad. It exploits the internal counter in
-- order to generate unique port-ids. However, they must be combined with the
-- actual node id of the node with the record shape. Thus the returned
-- association list is parametrized over this missing node id.
renderRecord :: Record a -> Dot (String, NodeId -> [(a,NodeId)])
renderRecord = render True
where
render _ (Field Nothing l) = return (escape l, const [])
render _ (Field (Just p) l) =
Dot $ \uq -> let pid = "n" ++ show uq
lbl = "<"++pid++"> "++escape l
in ([], succ uq, (lbl, \nId -> [(p,NodeId (show nId++":"++pid))]))
render horiz (HCat rs) = do
(lbls, ids) <- liftM unzip $ mapM (render True) rs
let rawLbl = concat (intersperse "|" lbls)
lbl = if horiz then "{{"++rawLbl++"}}" else "{"++rawLbl++"}"
return (lbl, \nId -> concatMap (\i -> i nId) ids)
render horiz (VCat rs) = do
(lbls, ids) <- liftM unzip $ mapM (render False) rs
let rawLbl = concat (intersperse "|" lbls)
lbl = if horiz then "{"++rawLbl++"}" else "{{"++rawLbl++"}}"
return (lbl, \nId -> concatMap (\i -> i nId) ids)
-- escape chars used for record label construction
escape = concatMap esc
esc '|' = "\\|"
esc '{' = "\\{"
esc '}' = "\\}"
esc '<' = "\\<"
esc '>' = "\\>"
esc c = [c]
-- | A generic version of record creation.
genRecord :: String -> Record a -> [(String,String)] -> Dot (NodeId, [(a,NodeId)])
genRecord shape rec attrs = do
(lbl, ids) <- renderRecord rec
i <- node ([("shape",shape),("label",lbl)] ++ attrs)
return (i, ids i)
-- | Create a record node with the given attributes. It returns the node-id of
-- the created node together with an association list mapping the port
-- idenfiers given in the record to their corresponding node-ids. This list is
-- ordered according to a left-to-rigth traversal of the record description.
record :: Record a -> [(String,String)] -> Dot (NodeId, [(a,NodeId)])
record = genRecord "record"
-- | A variant of "record" ignoring the port identifiers.
record' :: Record a -> [(String,String)] -> Dot (NodeId, [NodeId])
record' rec attrs = do (nId, ids) <- record rec attrs
return (nId, map snd ids)
-- | A variant of "record" ignoring the port to node-id association list.
record_ :: Record a -> [(String,String)] -> Dot NodeId
record_ rec attrs = liftM fst $ record rec attrs
-- | Like "record", but creates record nodes with rounded corners; i.e. uses
-- the \"Mrecord\" shape instead of the \"record\" shape.
mrecord :: Record a -> [(String,String)] -> Dot (NodeId, [(a,NodeId)])
mrecord = genRecord "Mrecord"
-- | A variant of "mrecord" ignoring the port identifiers.
mrecord' :: Record a -> [(String,String)] -> Dot (NodeId, [NodeId])
mrecord' rec attrs = do (nId, ids) <- mrecord rec attrs
return (nId, map snd ids)
-- | A variant of "mrecord" ignoring the port to node-id association list.
mrecord_ :: Record a -> [(String,String)] -> Dot NodeId
mrecord_ rec attrs = liftM fst $ mrecord rec attrs