Visitor¶

Stable ID: pattern.visitor
Kind: design-pattern
Status: stable
Source: skill/references/design-patterns/visitor.md

Purpose¶

Add operations across a stable heterogeneous structure without distributing each operation across every element type.

Use when¶

• The data structure is stable while operations grow independently.
• Double dispatch or exhaustive traversal provides clear ownership.

Avoid when¶

• Element types change frequently.
• Pattern matching or ordinary polymorphism is simpler.

Applicability¶

• Languages: any, python, q-kdbplus, cpp, rust, dart-flutter, typescript
• Related entries: None