Merge pull request JuliaAttic#187 from JuliaGraphs/dot

Dot

Author: sbromberger

REQUIRE

@@ -3,5 +3,5 @@ Compat 0.4.9
 GZip 0.2.16
 StatsBase 0.6.15
 LightXML 0.2.0
-ParserCombinator 1.6.3
+ParserCombinator 1.7.1
 Docile 0.5.3

src/LightGraphs.jl

@@ -6,7 +6,9 @@ using GZip
 using StatsBase
 using Base.Collections
 using LightXML
-using ParserCombinator.Parsers.GML
+using ParserCombinator
+using ParserCombinator.Parsers
+
 
 if VERSION < v"0.4.0-dev"
     try
@@ -95,7 +97,7 @@ CombinatorialAdjacency,
 a_star,
 
 # persistence
-readgraph, readgraphml, readgml, writegraphml, writegexf,
+readgraph, readgraphml, readgml, writegraphml, writegexf, readdot,
 
 # flow
 maximum_flow,

src/persistence.jl

@@ -9,6 +9,7 @@
 # header followed by a list of (comma-delimited) edges - src,dst.
 # Multiple graphs may be present in one file.
 
+
 function _read_one_graph(f::IO, n_v::Integer, n_e::Integer, directed::Bool)
     readedges = Set{@compat Tuple{Int,Int}}()
     if directed
@@ -188,7 +189,7 @@ end
 Can optionally restrict to a single graph by specifying a name in gname."""
 function readgml(filename::AbstractString, gname::AbstractString="")
     f = open(readall,filename)
-    p = parse_dict(f)
+    p = Parsers.GML.parse_dict(f)
     graphs = @compat(Dict{AbstractString, SimpleGraph}())
     for gs in p[:graph]
 
@@ -313,3 +314,42 @@ function writegexf(fname::AbstractString, g::SimpleGraph)
      close(f)
      return 1
  end
+
+
+function _readonedot(pg::ParserCombinator.Parsers.DOT.Graph)
+    isdir = pg.directed
+    nvg = length(Parsers.DOT.nodes(pg))
+    nodedict = Dict(zip(collect(Parsers.DOT.nodes(pg)), 1:nvg))
+    if isdir
+        g = DiGraph(nvg)
+    else
+        g = Graph(nvg)
+    end
+    for es in Parsers.DOT.edges(pg)
+        s = nodedict[es[1]]
+        d = nodedict[es[2]]
+        add_edge!(g, s, d)
+    end
+    return g
+end
+
+"""Returns a dictionary (name=>graph) from file `fn` stored in
+[DOT](https://en.wikipedia.org/wiki/DOT_(graph_description_language)) format.
+Can optionally restrict to a single graph by specifying a name in gname.
+"""
+function readdot(filename::AbstractString, gname::AbstractString="")
+    f = open(readall,filename)
+    p = Parsers.DOT.parse_dot(f)
+
+    graphs = @compat(Dict{AbstractString, SimpleGraph}())
+
+    for pg in p
+        isdir = pg.directed
+        possname = isdir? Parsers.DOT.StringID("Unnamed DiGraph") : Parsers.DOT.StringID("Unnamed Graph")
+        name = get(pg.id, possname).id
+        if (gname == "") || (name == gname)
+             graphs[name] = _readonedot(pg)
+        end
+    end
+    return graphs
+end

test/persistence.jl

@@ -42,6 +42,12 @@ gml2 = gs["Unnamed DiGraph"]
 gs = readgraph(joinpath(testdir, "testdata", "tutte-pathdigraph.jgz"), "pathdigraph")["pathdigraph"]
 @test gs == p2
 
+gs = readdot(joinpath(testdir, "testdata", "twographs.dot"))
+@test length(gs) == 2
+@test gs["g1"] == CompleteGraph(6)
+@test nv(gs["g2"]) == 4 && ne(gs["g2"]) == 6 && is_directed(gs["g2"])
+@test_throws KeyError readdot(joinpath(testdir, "testdata", "twographs.dot"))["badname"]
+
 # test the writes
 # redirecting stdout per https://thenewphalls.wordpress.com/2014/03/21/capturing-output-in-julia/
 origSTDOUT = STDOUT

test/testdata/onegraph.dot

@@ -0,0 +1,17 @@
+graph {
+        a -- b;
+        b -- c;
+        c -- d;
+        d -- e;
+        e -- f;
+        a -- f;
+        a -- c;
+        a -- d;
+        a -- e;
+        b -- d;
+        b -- e;
+        b -- f;
+        c -- e;
+        c -- f;
+        d -- f;
+    }

test/testdata/twographs.dot

@@ -0,0 +1,26 @@
+graph g1 {
+        a -- b;
+        b -- c;
+        c -- d;
+        d -- e;
+        e -- f;
+        a -- f;
+        a -- c;
+        a -- d;
+        a -- e;
+        b -- d;
+        b -- e;
+        b -- f;
+        c -- e;
+        c -- f;
+        d -- f;
+    }
+
+digraph g2 {
+        a -> b;
+        a -> c;
+        c -> b;
+        c -> e;
+        e -> e;
+        e -> b;
+    }