diff --git a/src/LightGraphs.jl b/src/LightGraphs.jl
index 5fcf70d5..a80b850c 100644
--- a/src/LightGraphs.jl
+++ b/src/LightGraphs.jl
@@ -139,7 +139,11 @@ include("core.jl")
         include("shortestpaths/floyd-warshall.jl")
         include("spectral.jl")
         include("operators.jl")
-        include("persistence.jl")
+        include("persistence/default.jl")
+        include("persistence/dot.jl")
+        include("persistence/gexf.jl")
+        include("persistence/gml.jl")
+        include("persistence/graphml.jl")
         include("randgraphs.jl")
         include("smallgraphs.jl")
         include("centrality/betweenness.jl")
diff --git a/src/persistence.jl b/src/persistence.jl
deleted file mode 100644
index 0caf1a3d..00000000
--- a/src/persistence.jl
+++ /dev/null
@@ -1,355 +0,0 @@
-# The format of simplegraph files is as follows:
-# a one line header: <num_vertices>, <num_edges>, {"d" | "u"}, <name>
-#   - num_vertices is an integer
-#   - num_edges is an integer
-#   - "d" for directed graph, "u" for undirected. Note that this
-#       option does not perform any additional edge construction; it's
-#       merely used to return the correct type of graph.
-#   - name is a string
-# 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
-        g = DiGraph(n_v)
-    else
-        g = Graph(n_v)
-    end
-    for i = 1:n_e
-        line = chomp(readline(f))
-        if length(line) > 0
-            src_s, dst_s = @compat(split(line,r"\s*,\s*"))
-            src = parse(Int, src_s)
-            dst = parse(Int, dst_s)
-            add_edge!(g, src, dst)
-        end
-    end
-    return g
-end
-
-function _skip_one_graph(f::IO, n_e::Integer)
-    for _ in 1:n_e
-        readline(f)
-    end
-end
-
-"""Returns a dictionary of (name=>graph) loaded from file `fn`."""
-function readgraph(fn::AbstractString, gname::AbstractString="")
-    graphs = @compat(Dict{AbstractString, SimpleGraph}())
-    f = GZip.open(fn,"r")        # should work even if uncompressed
-
-    while !eof(f)
-        line = strip(chomp(readline(f)))
-        if startswith(line,"#") || line == ""
-            next
-        else
-            nvstr, nestr, dirundir, graphname = @compat(split(line, r"s*,s*", limit=4))
-            n_v = parse(Int, nvstr)
-            n_e = parse(Int, nestr)
-            dirundir = strip(dirundir)
-            graphname = strip(graphname)
-            directed = !(dirundir == "u")
-            if (gname == "" || gname == graphname)
-                g = _read_one_graph(f, n_v, n_e, directed)
-                graphs[graphname] = g
-            else
-                _skip_one_graph(f, n_e)
-            end
-        end
-    end
-    return graphs
-end
-
-"""Writes a graph `g` with name `graphname` in a proprietary format
-to the IO stream designated by `io`.
-
-Returns 1 (number of graphs written).
-"""
-function write(io::IO, graphname::AbstractString, g::SimpleGraph)
-    # write header line
-    dir = is_directed(g)? "d" : "u"
-    line = join([nv(g), ne(g), dir, graphname], ",")
-    write(io, "$line\n")
-    # write edges
-    for e in edges(g)
-        write(io, "$(src(e)), $(dst(e))\n")
-    end
-    return 1
-end
-
-write(io::IO, g::Graph) = write(io, "Unnamed Graph", g)
-write(io::IO, g::DiGraph) = write(io, "Unnamed DiGraph", g)
-
-write(g::Graph) = write(STDOUT, "Unnamed Graph", g)
-write(g::DiGraph) = write(STDOUT, "Unnamed DiGraph", g)
-
-
-"""Writes a dictionary of (name=>graph) to a file `fn`,
-with default `GZip` compression.
-
-Returns number of graphs written.
-"""
-function write{S<:AbstractString, G<:SimpleGraph}(
-    graphs::@compat(Dict{S, G}),
-    fn::AbstractString;
-    compress::Bool=true
-)
-    if compress
-        f = GZip.open(fn,"w")
-    else
-        f = open(fn,"w")
-    end
-    ng = 0
-    for (gname, g) in graphs
-        ng += write(f, gname, g)
-    end
-    close(f)
-    return ng
-end
-
-write(
-    g::SimpleGraph,
-    gname::AbstractString,
-    fn::AbstractString;
-    compress::Bool=true
-) = write(@compat(Dict(gname=>g)), fn; compress=compress)
-
-write(g::Graph, fn::AbstractString; compress::Bool=true) = write(g, "Unnamed Graph", fn; compress=compress)
-write(g::DiGraph, fn::AbstractString; compress::Bool=true) = write(g, "Unnamed DiGraph", fn; compress=compress)
-
-function _process_graphml(e::XMLElement, isdirected::Bool)
-    nodes = @compat(Dict{AbstractString,Int}())
-    edges = @compat(Vector{Edge}())
-
-    nodeid = 1
-    for f in child_elements(e)
-        if name(f) == "node"
-            nodes[attribute(f, "id")] = nodeid
-            nodeid += 1
-        elseif name(f) == "edge"
-            n1 = attribute(f, "source")
-            n2 = attribute(f, "target")
-            push!(edges, Edge(nodes[n1], nodes[n2]))
-        else
-            error("Unknown node $(name(f))")
-        end
-    end
-    #Put data in graph
-    g = (isdirected ? DiGraph : Graph)(length(nodes))
-    for edge in edges
-        add_edge!(g, edge)
-    end
-    return g
-end
-
-"""Returns a dictionary (name=>graph) from file `fn` stored in
-[GraphML](http://en.wikipedia.org/wiki/GraphML) format.
-Can optionally restrict to a single graph by specifying a name in gname.
-"""
-function readgraphml(filename::AbstractString, gname::AbstractString="")
-    xdoc = parse_file(filename)
-    xroot = root(xdoc)  # an instance of XMLElement
-    name(xroot) == "graphml" || error("Not a GraphML file")
-
-    # traverse all its child nodes and print element names
-    graphs = @compat(Dict{AbstractString, SimpleGraph}())
-    for c in child_nodes(xroot)  # c is an instance of XMLNode
-        if is_elementnode(c)
-            e = XMLElement(c)  # this makes an XMLElement instance
-            if name(e) == "graph"
-                edgedefault = attribute(e, "edgedefault")
-                isdirected = edgedefault=="directed" ? true :
-                             edgedefault=="undirected" ? false : error("Unknown value of edgedefault: $edgedefault")
-                if has_attribute(e, "id")
-                    graphname = attribute(e, "id")
-                else
-                    if isdirected
-                        graphname = "Unnamed DiGraph"
-                    else
-                        graphname = "Unnamed Graph"
-                    end
-                end
-                if (gname == "" || gname == graphname)
-                    g = _process_graphml(e, isdirected)
-                    graphs[graphname] =  g
-                end
-            else
-                warn("Skipping unknown XML element $(name(e))")
-            end
-        end
-    end
-    return graphs
-end
-
-
-"""Returns a dictionary (name=>graph) from file `fn` stored in
-[GML](https://en.wikipedia.org/wiki/Graph_Modelling_Language) format.
-Can optionally restrict to a single graph by specifying a name in gname."""
-function readgml(filename::AbstractString, gname::AbstractString="")
-    f = open(readall,filename)
-    p = Parsers.GML.parse_dict(f)
-    graphs = @compat(Dict{AbstractString, SimpleGraph}())
-    for gs in p[:graph]
-
-        dir = @compat(Bool(get(gs, :directed, 0)))
-        nodes = [x[:id] for x in gs[:node]]
-        mapping = @compat(Dict{Int,Int}())
-        for (i,n) in enumerate(nodes)
-            mapping[n] = i
-        end
-
-        if dir
-            g = DiGraph(length(nodes))
-            graphname = get(gs, :name, "Unnamed DiGraph")
-        else
-            g = Graph(length(nodes))
-            graphname = get(gs, :name, "Unnamed Graph")
-        end
-        if (gname == "" || gname == graphname)
-            sds = @compat([(Int(x[:source]), Int(x[:target])) for x in gs[:edge]])
-            for (s,d) in (sds)
-                add_edge!(g, mapping[s], mapping[d])
-            end
-            (graphs[graphname] = g)
-        end
-    end
-    return graphs
-end
-
-
-"""
-Writes a graph `g` with name `gname`
-to a file `f` in the
-[Gexf](http://en.wikipedia.org/wiki/GraphML) format.
-
-Returns 1 (number of graphs written).
-"""
-function writegraphml(f::IO, g::SimpleGraph; gname::AbstractString = "Unnamed Graph")
-    xdoc = XMLDocument()
-    xroot = create_root(xdoc, "graphml")
-    set_attribute(xroot,"xmlns","http://graphml.graphdrawing.org/xmlns")
-    set_attribute(xroot,"xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance")
-    set_attribute(xroot,"xsi:schemaLocation","http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd")
-
-
-    xg = new_child(xroot, "graph")
-    set_attribute(xg,"id",gname)
-    strdir = is_directed(g) ? "directed" : "undirected"
-    set_attribute(xg,"edgedefault",strdir)
-
-    for i=1:nv(g)
-        xv = new_child(xg, "node")
-        set_attribute(xv,"id","n$(i-1)")
-    end
-
-    m = 0
-    for e in edges(g)
-        xe = new_child(xg, "edge")
-        set_attribute(xe,"id","e$m")
-        set_attribute(xe,"source","n$(src(e)-1)")
-        set_attribute(xe,"target","n$(dst(e)-1)")
-        m += 1
-    end
-
-    show(f, xdoc)
-    return 1
-end
-
-writegraphml(g::SimpleGraph; gname::AbstractString = "Unnamed Graph") = writegraphml(STDOUT, g; gname=gname)
-
-function writegraphml(fname::AbstractString, g::SimpleGraph; gname::AbstractString = "Unnamed Graph")
-    f = open(fname, "w")
-     writegraphml(f, g; gname=gname)
-     close(f)
-     return 1
- end
-
-"""
-Writes a graph `g` with name `gname`
-to a file `f` in the
-[Gexf](http://gexf.net/format/) format.
-
-Returns 1 (number of graphs written).
-"""
-function writegexf(f::IO, g::SimpleGraph)
-    xdoc = XMLDocument()
-    xroot = create_root(xdoc, "gexf")
-    set_attribute(xroot,"xmlns","http://www.gexf.net/1.2draft")
-    set_attribute(xroot,"version","1.2")
-    set_attribute(xroot,"xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance")
-    set_attribute(xroot,"xsi:schemaLocation","http://www.gexf.net/1.2draft/gexf.xsd")
-
-    xmeta = new_child(xroot, "meta")
-    xg = new_child(xroot, "graph")
-    strdir = is_directed(g) ? "directed" : "undirected"
-    set_attribute(xg,"defaultedgetype",strdir)
-
-    xnodes = new_child(xg, "nodes")
-    for i=1:nv(g)
-        xv = new_child(xnodes, "node")
-        set_attribute(xv,"id","$(i-1)")
-    end
-
-    xedges = new_child(xg, "edges")
-    m=0
-    for e in edges(g)
-        xe = new_child(xedges, "edge")
-        set_attribute(xe,"id","$m")
-        set_attribute(xe,"source","$(src(e)-1)")
-        set_attribute(xe,"target","$(dst(e)-1)")
-        m+=1
-    end
-
-    show(f, xdoc)
-    return 1
-end
-
-writegexf(g::SimpleGraph) = writegexf(STDOUT, g)
-
-function writegexf(fname::AbstractString, g::SimpleGraph)
-    f = open(fname, "w")
-     writegexf(f, g)
-     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
diff --git a/src/persistence/default.jl b/src/persistence/default.jl
new file mode 100644
index 00000000..9ee500c8
--- /dev/null
+++ b/src/persistence/default.jl
@@ -0,0 +1,121 @@
+# The format of simplegraph files is as follows:
+# a one line header: <num_vertices>, <num_edges>, {"d" | "u"}, <name>
+#   - num_vertices is an integer
+#   - num_edges is an integer
+#   - "d" for directed graph, "u" for undirected. Note that this
+#       option does not perform any additional edge construction; it's
+#       merely used to return the correct type of graph.
+#   - name is a string
+# 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
+        g = DiGraph(n_v)
+    else
+        g = Graph(n_v)
+    end
+    for i = 1:n_e
+        line = chomp(readline(f))
+        if length(line) > 0
+            src_s, dst_s = @compat(split(line,r"\s*,\s*"))
+            src = parse(Int, src_s)
+            dst = parse(Int, dst_s)
+            add_edge!(g, src, dst)
+        end
+    end
+    return g
+end
+
+function _skip_one_graph(f::IO, n_e::Integer)
+    for _ in 1:n_e
+        readline(f)
+    end
+end
+
+"""Returns a dictionary of (name=>graph) loaded from file `fn`."""
+function readgraph(fn::AbstractString, gname::AbstractString="")
+    graphs = @compat(Dict{AbstractString, SimpleGraph}())
+    f = GZip.open(fn,"r")        # should work even if uncompressed
+
+    while !eof(f)
+        line = strip(chomp(readline(f)))
+        if startswith(line,"#") || line == ""
+            next
+        else
+            nvstr, nestr, dirundir, graphname = @compat(split(line, r"s*,s*", limit=4))
+            n_v = parse(Int, nvstr)
+            n_e = parse(Int, nestr)
+            dirundir = strip(dirundir)
+            graphname = strip(graphname)
+            directed = !(dirundir == "u")
+            if (gname == "" || gname == graphname)
+                g = _read_one_graph(f, n_v, n_e, directed)
+                graphs[graphname] = g
+            else
+                _skip_one_graph(f, n_e)
+            end
+        end
+    end
+    return graphs
+end
+
+
+"""Writes a graph `g` with name `graphname` in a proprietary format
+to the IO stream designated by `io`.
+
+Returns 1 (number of graphs written).
+"""
+function write(io::IO, graphname::AbstractString, g::SimpleGraph)
+    # write header line
+    dir = is_directed(g)? "d" : "u"
+    line = join([nv(g), ne(g), dir, graphname], ",")
+    write(io, "$line\n")
+    # write edges
+    for e in edges(g)
+        write(io, "$(src(e)), $(dst(e))\n")
+    end
+    return 1
+end
+
+write(io::IO, g::Graph) = write(io, "Unnamed Graph", g)
+write(io::IO, g::DiGraph) = write(io, "Unnamed DiGraph", g)
+
+write(g::Graph) = write(STDOUT, "Unnamed Graph", g)
+write(g::DiGraph) = write(STDOUT, "Unnamed DiGraph", g)
+
+
+"""Writes a dictionary of (name=>graph) to a file `fn`,
+with default `GZip` compression.
+
+Returns number of graphs written.
+"""
+function write{S<:AbstractString, G<:SimpleGraph}(
+    graphs::@compat(Dict{S, G}),
+    fn::AbstractString;
+    compress::Bool=true
+)
+    if compress
+        f = GZip.open(fn,"w")
+    else
+        f = open(fn,"w")
+    end
+    ng = 0
+    for (gname, g) in graphs
+        ng += write(f, gname, g)
+    end
+    close(f)
+    return ng
+end
+
+write(
+    g::SimpleGraph,
+    gname::AbstractString,
+    fn::AbstractString;
+    compress::Bool=true
+) = write(@compat(Dict(gname=>g)), fn; compress=compress)
+
+write(g::Graph, fn::AbstractString; compress::Bool=true) = write(g, "Unnamed Graph", fn; compress=compress)
+write(g::DiGraph, fn::AbstractString; compress::Bool=true) = write(g, "Unnamed DiGraph", fn; compress=compress)
diff --git a/src/persistence/dot.jl b/src/persistence/dot.jl
new file mode 100644
index 00000000..664d3051
--- /dev/null
+++ b/src/persistence/dot.jl
@@ -0,0 +1,39 @@
+# TODO: implement writedot
+
+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
diff --git a/src/persistence/gexf.jl b/src/persistence/gexf.jl
new file mode 100644
index 00000000..7b0b4946
--- /dev/null
+++ b/src/persistence/gexf.jl
@@ -0,0 +1,50 @@
+# TODO: implement readgexf
+
+"""
+Writes a graph `g` with name `gname`
+to a file `f` in the
+[Gexf](http://gexf.net/format/) format.
+
+Returns 1 (number of graphs written).
+"""
+function writegexf(f::IO, g::SimpleGraph)
+    xdoc = XMLDocument()
+    xroot = create_root(xdoc, "gexf")
+    set_attribute(xroot,"xmlns","http://www.gexf.net/1.2draft")
+    set_attribute(xroot,"version","1.2")
+    set_attribute(xroot,"xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance")
+    set_attribute(xroot,"xsi:schemaLocation","http://www.gexf.net/1.2draft/gexf.xsd")
+
+    xmeta = new_child(xroot, "meta")
+    xg = new_child(xroot, "graph")
+    strdir = is_directed(g) ? "directed" : "undirected"
+    set_attribute(xg,"defaultedgetype",strdir)
+
+    xnodes = new_child(xg, "nodes")
+    for i=1:nv(g)
+        xv = new_child(xnodes, "node")
+        set_attribute(xv,"id","$(i-1)")
+    end
+
+    xedges = new_child(xg, "edges")
+    m=0
+    for e in edges(g)
+        xe = new_child(xedges, "edge")
+        set_attribute(xe,"id","$m")
+        set_attribute(xe,"source","$(src(e)-1)")
+        set_attribute(xe,"target","$(dst(e)-1)")
+        m+=1
+    end
+
+    show(f, xdoc)
+    return 1
+end
+
+writegexf(g::SimpleGraph) = writegexf(STDOUT, g)
+
+function writegexf(fname::AbstractString, g::SimpleGraph)
+    f = open(fname, "w")
+     writegexf(f, g)
+     close(f)
+     return 1
+ end
diff --git a/src/persistence/gml.jl b/src/persistence/gml.jl
new file mode 100644
index 00000000..c5ef834b
--- /dev/null
+++ b/src/persistence/gml.jl
@@ -0,0 +1,35 @@
+# TODO: implement writegml
+
+"""Returns a dictionary (name=>graph) from file `fn` stored in
+[GML](https://en.wikipedia.org/wiki/Graph_Modelling_Language) format.
+Can optionally restrict to a single graph by specifying a name in gname."""
+function readgml(filename::AbstractString, gname::AbstractString="")
+    f = open(readall,filename)
+    p = Parsers.GML.parse_dict(f)
+    graphs = @compat(Dict{AbstractString, SimpleGraph}())
+    for gs in p[:graph]
+
+        dir = @compat(Bool(get(gs, :directed, 0)))
+        nodes = [x[:id] for x in gs[:node]]
+        mapping = @compat(Dict{Int,Int}())
+        for (i,n) in enumerate(nodes)
+            mapping[n] = i
+        end
+
+        if dir
+            g = DiGraph(length(nodes))
+            graphname = get(gs, :name, "Unnamed DiGraph")
+        else
+            g = Graph(length(nodes))
+            graphname = get(gs, :name, "Unnamed Graph")
+        end
+        if (gname == "" || gname == graphname)
+            sds = @compat([(Int(x[:source]), Int(x[:target])) for x in gs[:edge]])
+            for (s,d) in (sds)
+                add_edge!(g, mapping[s], mapping[d])
+            end
+            (graphs[graphname] = g)
+        end
+    end
+    return graphs
+end
diff --git a/src/persistence/graphml.jl b/src/persistence/graphml.jl
new file mode 100644
index 00000000..ed821902
--- /dev/null
+++ b/src/persistence/graphml.jl
@@ -0,0 +1,112 @@
+# TODO: implement writing a dict of graphs
+
+function _process_graphml(e::XMLElement, isdirected::Bool)
+    nodes = @compat(Dict{AbstractString,Int}())
+    edges = @compat(Vector{Edge}())
+
+    nodeid = 1
+    for f in child_elements(e)
+        if name(f) == "node"
+            nodes[attribute(f, "id")] = nodeid
+            nodeid += 1
+        elseif name(f) == "edge"
+            n1 = attribute(f, "source")
+            n2 = attribute(f, "target")
+            push!(edges, Edge(nodes[n1], nodes[n2]))
+        else
+            error("Unknown node $(name(f))")
+        end
+    end
+    #Put data in graph
+    g = (isdirected ? DiGraph : Graph)(length(nodes))
+    for edge in edges
+        add_edge!(g, edge)
+    end
+    return g
+end
+
+"""Returns a dictionary (name=>graph) from file `fn` stored in
+[GraphML](http://en.wikipedia.org/wiki/GraphML) format.
+Can optionally restrict to a single graph by specifying a name in gname.
+"""
+function readgraphml(filename::AbstractString, gname::AbstractString="")
+    xdoc = parse_file(filename)
+    xroot = root(xdoc)  # an instance of XMLElement
+    name(xroot) == "graphml" || error("Not a GraphML file")
+
+    # traverse all its child nodes and print element names
+    graphs = @compat(Dict{AbstractString, SimpleGraph}())
+    for c in child_nodes(xroot)  # c is an instance of XMLNode
+        if is_elementnode(c)
+            e = XMLElement(c)  # this makes an XMLElement instance
+            if name(e) == "graph"
+                edgedefault = attribute(e, "edgedefault")
+                isdirected = edgedefault=="directed" ? true :
+                             edgedefault=="undirected" ? false : error("Unknown value of edgedefault: $edgedefault")
+                if has_attribute(e, "id")
+                    graphname = attribute(e, "id")
+                else
+                    if isdirected
+                        graphname = "Unnamed DiGraph"
+                    else
+                        graphname = "Unnamed Graph"
+                    end
+                end
+                if (gname == "" || gname == graphname)
+                    g = _process_graphml(e, isdirected)
+                    graphs[graphname] =  g
+                end
+            else
+                warn("Skipping unknown XML element $(name(e))")
+            end
+        end
+    end
+    return graphs
+end
+
+"""
+Writes a graph `g` with name `gname`
+to a file `f` in the
+[GraphML](http://en.wikipedia.org/wiki/GraphML) format.
+
+Returns 1 (number of graphs written).
+"""
+function writegraphml(f::IO, g::SimpleGraph; gname::AbstractString = "Unnamed Graph")
+    xdoc = XMLDocument()
+    xroot = create_root(xdoc, "graphml")
+    set_attribute(xroot,"xmlns","http://graphml.graphdrawing.org/xmlns")
+    set_attribute(xroot,"xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance")
+    set_attribute(xroot,"xsi:schemaLocation","http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd")
+
+
+    xg = new_child(xroot, "graph")
+    set_attribute(xg,"id",gname)
+    strdir = is_directed(g) ? "directed" : "undirected"
+    set_attribute(xg,"edgedefault",strdir)
+
+    for i=1:nv(g)
+        xv = new_child(xg, "node")
+        set_attribute(xv,"id","n$(i-1)")
+    end
+
+    m = 0
+    for e in edges(g)
+        xe = new_child(xg, "edge")
+        set_attribute(xe,"id","e$m")
+        set_attribute(xe,"source","n$(src(e)-1)")
+        set_attribute(xe,"target","n$(dst(e)-1)")
+        m += 1
+    end
+
+    show(f, xdoc)
+    return 1
+end
+
+writegraphml(g::SimpleGraph; gname::AbstractString = "Unnamed Graph") = writegraphml(STDOUT, g; gname=gname)
+
+function writegraphml(fname::AbstractString, g::SimpleGraph; gname::AbstractString = "Unnamed Graph")
+    f = open(fname, "w")
+     writegraphml(f, g; gname=gname)
+     close(f)
+     return 1
+ end