Zig's Comptime: Powerful Yet Restrained Metaprogramming

Zig's comptime feature is renowned for its capabilities: generics, conditional compilation, and more. However, it's deliberately restrictive, disallowing dynamic code generation, custom syntax extensions, runtime type information (RTTI), and I/O. This article explores the reasoning behind these limitations, showcasing how Zig achieves efficient and understandable metaprogramming through partial evaluation and type specialization. A custom printing function example demonstrates how Zig performs type-safe runtime reflection without RTTI. The article concludes by praising Zig's unique elegance in metaprogramming; while less powerful than alternatives, it's remarkably efficient and easy to use in practice.