graph_api_lib/walker/steps/
default_context.rs

1use crate::graph::{EdgeReference, VertexReference};
2use crate::walker::builder::{EdgeWalkerBuilder, VertexWalkerBuilder};
3use crate::walker::steps::{
4    ContextRef, DefaultEdgeContext, DefaultVertexContext, EdgeContext, VertexContext,
5};
6use crate::walker::{EdgeWalker, VertexWalker};
7use include_doc::function_body;
8
9impl<'graph, Mutability, Graph, Walker> VertexWalkerBuilder<'graph, Mutability, Graph, Walker>
10where
11    Graph: crate::graph::Graph,
12    Walker: VertexWalker<'graph, Graph = Graph>,
13{
14    /// # Default Context Step
15    ///
16    /// The `push_default_context` step is a specialized version of the `push_context` step that
17    /// automatically stores the current element's ID and data in the context. This provides a
18    /// convenient way to preserve information about elements as you traverse through the graph.
19    ///
20    /// ## Visual Diagram
21    ///
22    /// Before push_default_context step (traversal with regular elements):
23    /// ```text
24    ///   [Person A]* --- created ---> [Project X]*  
25    ///    |
26    ///   knows
27    ///    |
28    ///   [Person B]*
29    /// ```
30    ///
31    /// After push_default_context step (elements with default context):
32    /// ```text
33    ///   [Person A]* + {vertex_id: id_a, vertex: Person{name: "A", age: 30}} --- created ---> [Project X]* + {vertex_id: id_x, vertex: Project{name: "X"}}
34    ///    |
35    ///   knows
36    ///    |
37    ///   [Person B]* + {vertex_id: id_b, vertex: Person{name: "B", age: 25}}
38    /// ```
39    ///
40    /// ## Parameters
41    ///
42    /// None
43    ///
44    /// ## Return Value
45    ///
46    /// Returns a traversal with the same elements, but with each element's ID and data stored in its context.
47    ///
48    /// ## Example
49    ///
50    /// ```rust
51    #[doc = function_body!("examples/default_context.rs", basic_example, [])]
52    /// ```
53    ///
54    /// ## Notes
55    ///
56    /// - Default context for vertices includes:
57    ///   - `vertex_id`: The ID of the vertex
58    ///   - `vertex`: The vertex data (cloned from the graph)
59    /// - Type safety is maintained as the vertex/edge types are preserved
60    /// - This step requires that your vertex/edge types implement Clone + 'static
61    /// - More concise than manual context handling for common use cases
62    /// - Especially useful when you need to preserve information across multiple traversal steps
63    /// - Combines well with other context operations for complex data gathering
64    pub fn push_default_context(
65        self,
66    ) -> VertexWalkerBuilder<
67        'graph,
68        Mutability,
69        Graph,
70        VertexContext<
71            'graph,
72            Walker,
73            impl Fn(
74                &Graph::VertexReference<'_>,
75                &Walker::Context,
76            )
77                -> ContextRef<DefaultVertexContext<Graph::VertexId, Graph::Vertex>, Walker::Context>,
78            ContextRef<DefaultVertexContext<Graph::VertexId, Graph::Vertex>, Walker::Context>,
79        >,
80    >
81    where
82        Graph::Vertex: Clone + 'static,
83    {
84        self.push_context(|vertex, _context| DefaultVertexContext {
85            vertex_id: vertex.id(),
86            vertex: vertex.weight().clone(),
87        })
88    }
89}
90
91impl<'graph, Mutability, Graph, Walker> EdgeWalkerBuilder<'graph, Mutability, Graph, Walker>
92where
93    Graph: crate::graph::Graph,
94    Walker: EdgeWalker<'graph, Graph = Graph>,
95    <Walker as crate::walker::Walker<'graph>>::Context: Clone + 'static,
96{
97    /// # Default Context Step
98    ///
99    /// A specialized version of the `push_context` step for edges that automatically
100    /// stores the current edge's ID and data in the context.
101    ///
102    /// See the documentation for [`VertexWalkerBuilder::push_default_context`] for more details.
103    pub fn push_default_context(
104        self,
105    ) -> EdgeWalkerBuilder<
106        'graph,
107        Mutability,
108        Graph,
109        EdgeContext<
110            'graph,
111            Walker,
112            impl Fn(
113                &Graph::EdgeReference<'_>,
114                &Walker::Context,
115            )
116                -> ContextRef<DefaultEdgeContext<Graph::EdgeId, Graph::Edge>, Walker::Context>,
117            ContextRef<DefaultEdgeContext<Graph::EdgeId, Graph::Edge>, Walker::Context>,
118        >,
119    >
120    where
121        Graph::Edge: Clone + 'static,
122    {
123        self.push_context(|edge, _context| DefaultEdgeContext {
124            edge_id: edge.id(),
125            edge: edge.weight().clone(),
126        })
127    }
128}
graph_api_lib/walker/steps/default_context.rs

graph_api_lib/walker/steps/
default_context.rs
