Fix #840: Add GraphML serializer

docs/source/api/serialization.rst

@@ -8,5 +8,6 @@ Serialization
 
    rustworkx.node_link_json
    rustworkx.read_graphml
+   rustworkx.write_graphml
    rustworkx.from_node_link_json_file
    rustworkx.parse_node_link_json

releasenotes/notes/write_graphml-624c10b6f7592ee1.yaml

@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    Added a new function :func:`~rustworkx.write_graphml` that writes
+    a list of rustworkx graph objects to a file in GraphML format.
+other:
+  - |
+    When graphs read with :func:`~rustworkx.read_graphml` include IDs,
+    these IDs are now stored in the graph attributes.

rustworkx/__init__.py

@@ -2279,3 +2279,9 @@ def single_source_all_shortest_paths(
         For most use cases, consider using `dijkstra_shortest_paths` for a single shortest path, which runs much faster.
     """
     raise TypeError(f"Invalid Input Type {type(graph)} for graph")
+
+
+@_rustworkx_dispatch
+def write_graphml(graph, path, /, keys, compression):
+    """ """
+    raise TypeError(f"Invalid Input Type {type(graph)} for graph")

rustworkx/__init__.pyi

@@ -163,6 +163,9 @@ from .rustworkx import directed_barabasi_albert_graph as directed_barabasi_alber
 from .rustworkx import undirected_random_bipartite_graph as undirected_random_bipartite_graph
 from .rustworkx import directed_random_bipartite_graph as directed_random_bipartite_graph
 from .rustworkx import read_graphml as read_graphml
+from .rustworkx import graph_write_graphml as graph_write_graphml
+from .rustworkx import digraph_write_graphml as digraph_write_graphml
+from .rustworkx import GraphMLKey as GraphMLKey
 from .rustworkx import digraph_node_link_json as digraph_node_link_json
 from .rustworkx import graph_node_link_json as graph_node_link_json
 from .rustworkx import from_node_link_json_file as from_node_link_json_file
@@ -662,3 +665,10 @@ def is_bipartite(graph: PyGraph[_S, _T] | PyDiGraph[_S, _T]) -> bool: ...
 def condensation(
     graph: PyDiGraph | PyGraph, /, sccs: list[int] | None = ...
 ) -> PyDiGraph | PyGraph: ...
+def write_graphml(
+    graph: PyGraph | PyDiGraph,
+    path: str,
+    /,
+    keys: list[GraphMLKey] | None = ...,
+    compression: str | None = ...,
+) -> None: ...

rustworkx/rustworkx.pyi

@@ -68,6 +68,30 @@ class ColoringStrategy:
     Saturation: Any
     IndependentSet: Any
 
+@final
+class GraphMLDomain:
+    Node: GraphMLDomain
+    Edge: GraphMLDomain
+    Graph: GraphMLDomain
+    All: GraphMLDomain
+
+@final
+class GraphMLType:
+    Boolean: GraphMLType
+    Int: GraphMLType
+    Float: GraphMLType
+    Double: GraphMLType
+    String: GraphMLType
+    Long: GraphMLType
+
+@final
+class GraphMLKey:
+    id: str
+    domain: GraphMLDomain
+    name: str
+    ty: GraphMLType
+    default: Any
+
 # Cartesian product
 
 def digraph_cartesian_product(
@@ -685,6 +709,20 @@ def read_graphml(
     /,
     compression: str | None = ...,
 ) -> list[PyGraph | PyDiGraph]: ...
+def graph_write_graphml(
+    graph: PyGraph,
+    path: str,
+    /,
+    keys: list[GraphMLKey] | None = ...,
+    compression: str | None = ...,
+) -> None: ...
+def digraph_write_graphml(
+    graph: PyDiGraph,
+    path: str,
+    /,
+    keys: list[GraphMLKey] | None = ...,
+    compression: str | None = ...,
+) -> None: ...
 def digraph_node_link_json(
     graph: PyDiGraph[_S, _T],
     /,