Status: IN
Interpreter draws on both Composite and Visitor among the GoF patterns: its abstract syntax tree is an instance of Composite (with terminal expressions as leaves and nonterminal expressions as composites), and Visitor is recommended for adding operations such as type-checking, optimization, and code generation to the AST without modifying grammar classes.
Interpreter uniquely requires both Composite's structure and Visitor's extensibility
Depends on (SL): interpreter-abstract-syntax-tree-is-composite, visitor-recommended-for-interpreter-extension