Functional Language Features: Iterators and Closures

Rust incorporates functional programming concepts including closures and iterators, both offering zero-cost abstractions with compile-time optimizations.

This chapter covers:

• Closures: Anonymous functions that capture their environment
• Iterators: Lazy evaluation for processing data sequences
• Performance: Both compile to equivalent machine code as hand-written loops
• Practical application: Refactoring I/O operations using functional patterns

These features enable expressive, high-performance code while maintaining Rust’s safety guarantees.