El rng

include/graph/graph.hpp

@@ -17,6 +17,8 @@
  * @ingroup general_concepts
  */
 
+#define ENABLE_EDGELIST_RANGE
+
 #include <ranges>
 #include <concepts>
 #include <type_traits>
@@ -41,16 +43,16 @@
 // VR                       Vertex Range
 // VI        ui,vi          Vertex Iterator
 // VVF                      Vertex Value Function: vvf(u) -> value
-// VVP       vvp            Vertex Value Projection function vvp(x) --> vertex_descriptor<>
 //
 // E                        Edge type
 //           uv,vw          Edge reference
 // EV                       Edge Value (user-defined or void)
 // ER                       Edge Range
 // EI        uvi,vwi        Edge iterator
 // EVF       evf            Edge Value Function: evf(uv) -> value
-// EVP       evp            Edge Value Production function: evp(y) -> edge_descriptor<>
 //
+// ELR       elr            Edge List Range; an arbitrary range where its values can be projected to be an edge_descriptor.
+// Proj      proj           Projection function: proj(y) -> edge_descriptor<...>, where y is the value type of an ELR
 
 #ifndef GRAPH_HPP
 #  define GRAPH_HPP
@@ -203,6 +205,14 @@ template <class G>
 concept sourced_adjacency_list =
       adjacency_list<G> && sourced_edge<G, edge_t<G>> && requires(G&& g, edge_reference_t<G> uv) { edge_id(g, uv); };
 
+
+#  ifdef ENABLE_EDGELIST_RANGE
+template <class ELR>
+concept basic_edgelist_range = ranges::forward_range<ELR> && negation_v<index_adjacency_list<ELR>>;
+template <class ELR>
+concept edgelist_range = ranges::forward_range<ELR> && negation_v<adjacency_list<ELR>>;
+#  endif
+
 //
 // property concepts
 //

include/graph/graph_descriptors.hpp

@@ -41,6 +41,11 @@ using copyable_vertex_t = vertex_descriptor<VId, void, VV>; // {id, value}
 //
 template <class VId, bool Sourced, class E, class EV>
 struct edge_descriptor {
+  using source_id_type = VId;
+  using target_id_type = VId;
+  using edge_type      = E;
+  using value_type     = EV;
+
   VId source_id;
   VId target_id;
   E   edge;
@@ -49,41 +54,76 @@ struct edge_descriptor {
 
 template <class VId, class E>
 struct edge_descriptor<VId, true, E, void> {
+  using source_id_type = VId;
+  using target_id_type = VId;
+  using edge_type      = E;
+  using value_type     = void;
+
   VId source_id;
   VId target_id;
   E   edge;
 };
 template <class VId>
 struct edge_descriptor<VId, true, void, void> {
+  using source_id_type = VId;
+  using target_id_type = VId;
+  using edge_type      = void;
+  using value_type     = void;
+
   VId source_id;
   VId target_id;
 };
 template <class VId, class EV>
 struct edge_descriptor<VId, true, void, EV> {
+  using source_id_type = VId;
+  using target_id_type = VId;
+  using edge_type      = void;
+  using value_type     = EV;
+
   VId source_id;
   VId target_id;
   EV  value;
 };
 
 template <class VId, class E, class EV>
 struct edge_descriptor<VId, false, E, EV> {
+  using source_id_type = void;
+  using target_id_type = VId;
+  using edge_type      = void;
+  using value_type     = EV;
+
   VId target_id;
   E   edge;
   EV  value;
 };
 template <class VId, class E>
 struct edge_descriptor<VId, false, E, void> {
+  using source_id_type = void;
+  using target_id_type = VId;
+  using edge_type      = E;
+  using value_type     = void;
+
   VId target_id;
   E   edge;
 };
 
 template <class VId, class EV>
 struct edge_descriptor<VId, false, void, EV> {
+  using source_id_type = void;
+  using target_id_type = VId;
+  using edge_type      = void;
+  using value_type     = EV;
+
   VId target_id;
   EV  value;
 };
 template <class VId>
 struct edge_descriptor<VId, false, void, void> {
+  using source_id_type = void;
+  using target_id_type = VId;
+  using edge_type      = void;
+  using value_type     = void;
+
   VId target_id;
 };