C++26 Reflection — hands-on blog series

A runnable, example-driven walkthrough of C++26 static reflection (P2996 and friends), built on a pinned bloomberg/clang-p2996 Docker image.

Every post has working code you can compile and run in under a minute. Every example is also mirrored on Compiler Explorer so you can play without installing anything.

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Try it now

Option A — Compiler Explorer (zero install)

Each post's examples/godbolt.md lists permalinks. Click, edit, share.

Option B — Local container (arm64 or x86_64 Linux/macOS)

Requires Docker (or Colima/OrbStack on macOS). Build once, then use the wrappers.

./build.sh                              # 30-60 min, one-time; arm64-native
./cpp hello_reflection.cpp -o hello     # compile with clang-p2996
./run ./hello                           # run inside the container

Toolchain: pinned to bloomberg/clang-p2996@9ffb96e3ce36. The Dockerfile builds LLVM for AArch64 only with minimal components to keep build time and image size reasonable.

All examples compile with:

clang++ -std=c++26 -freflection -stdlib=libc++ ...

which is what ./cpp wraps.

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The series

Status legend: ⬜ planned · 🚧 drafting · ✅ published

Arc 1 — Foundations

#	Post	Audience	Status
1	Why C++26 reflection matters	Polyglot	⬜
2	Your first ^^: reflecting types, walking members	Mixed	⬜
3	Splicing: [: r :] and round-tripping reflections	Working C++	⬜
4	template for: iterating reflections at compile time	Working C++	⬜

Arc 2 — Everyday wins (lib/reflect_print)

#	Post	Audience	Status
5	Goodbye magic_enum: enum reflection done right	Working C++	⬜
6	Auto-generating std::formatter<T> for any aggregate	Working C++	⬜
7	Deriving equality, hashing, and ordering from structure	Working C++	⬜

Arc 3 — Serialization (lib/reflect_json)

#	Post	Audience	Status
8	A 40-line JSON serializer with reflection	Working C++	⬜
9	Annotations: tag-driven serialization in C++	Working C++	⬜
10	Deserialization and std::expected error paths	Working C++	⬜
11	One codegen, many wire formats: YAML, TOML, MessagePack	Working C++	⬜

Arc 4 — Ambitious ports

#	Post	Audience	Status
12	CLI parsing: struct → typed command-line parser	Working C++	⬜
13	A tiny ORM: struct → SQL	Working C++	⬜
14	Autowired dependency injection	Working C++	⬜
15	Auto-generated mocks from interfaces	Working C++	⬜

Arc 5 — Advanced / synthesis

#	Post	Audience	Status
16	define_aggregate: synthesizing types at compile time	Working C++	⬜
17	Replacing Qt's MOC with reflection	Working C++	⬜
18	Capstone: C++26 reflection vs Rust, C#, Java, TS, Go, Python	Polyglot	⬜

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How to follow

• Star the repo; each published post ships as a tagged release (post-01, post-02, ...).
• Every post links to a GitHub Discussion thread — that's where questions and corrections live.
• Issues are reserved for bugs in example code or the Docker toolchain.

Caveats

• The Bloomberg fork is explicitly not production-ready per its own README. Use it to learn and experiment with P2996, not to ship.
• The pinned SHA will bump periodically as P2996 evolves. Old posts link to specific SHAs so historical examples always compile.
• Annotations (P3394) syntax may change; posts that depend on annotations name the exact SHA they were verified against.

Local verification

./verify.sh walks every post's examples/ directory, compiles + runs each sample, and prints pass/fail. Required before tagging a release.

License

Code examples: MIT. Prose: CC BY 4.0.