C++26 is introducing compile-time reflection, and this post compares it with reflection capabilities in Python, Java, C#, and Rust using a concrete example: implementing a generic object_to_string function. Python uses runtime __dict__ lookups, Java and C# use runtime reflection APIs backed by their runtime environments, and Rust uses procedural macros (which are compile-time code generation but not true reflection). C++26 reflection uses the ^^ operator to enter reflection space, std::meta functions to traverse it, and splicers [:...:] to leave it — all evaluated at compile time, making it a zero-cost abstraction. The key distinction is that C++ reflection evaporates after constant evaluation, producing code equivalent to hand-written specializations, unlike Java/C# where reflection incurs runtime overhead. Rust's procedural macros are limited to token-level transformations without the ability to query type definitions, making them code generation rather than true reflection.
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