Mutate Context

The mutate_context step allows you to modify context data during a graph traversal without affecting the traversal position. This provides a way to update state or accumulate information as you move through the graph.

In this diagram:

• An Input Stream contains elements A and B, each associated with a context value.
• The .mutate_context(|e, ctx| { /* modify ctx */ }) step is applied, allowing in-place modification of the context associated with each element.
• The resulting Output Stream shows the same elements (A and B) but with modified context values.
• This demonstrates that mutate_context affects only the context data, not the traversal elements or position.

Syntax

walker.mutate_context(|element, context| {
    // Modify context in-place via mutable reference
})

Parameters

• callback: A function that takes:
  • A reference to the current element (vertex or edge)
  • A mutable reference to the current context
  • Performs in-place modifications to the context

Return Value

Returns a new walker with the same position but modified context data.