C++ style

Layout is Google; naming is the C++ standard library's.

• Formatting: clang-format with BasedOnStyle: Google (see .clang-format). Headers use .h, sources use .cc, include guards use the BAML_..._H_ form.
• Naming: std-library convention, per the C++ Core Guidelines (NL.10: prefer underscore_style, consistent with the ISO standard library) -- the same convention Boost uses. Enforced by clang-tidy readability-identifier-naming (see .clang-tidy).

The naming rules

Entity	Case	Examples
types	snake_case	baml::variant, baml::future, baml::lit, baml::error, baml::thrown<U>, detail::call_state
functions and methods	snake_case	baml::match, future::cancel, codec<T>::encode, detail::call_sync
constants	snake_case	baml::unset (type baml::unset_t, the nullopt/nullopt_t pattern)
enumerators	snake_case	lit_shape::integer (int/bool/enum are keywords; spell them out)
template parameters	CamelCase	T, Ret, ThrownU, WriteValue
macros	BAML_UPPER	BAML_LIT, BAML_TEST
private members	trailing _	state_, engine_call_id_

baml::variant is the one vocabulary drift from BAML's own terminology: lowercase union is a C++ keyword, and variant is the std name for the same shape.

Exceptions to the rules

1. extern "C" symbols and everything in the C ABI header (baml_cffi.h: BamlApiV1, BamlBuffer, ...) keep their contract spellings.
2. Generated protobuf code (pb/) keeps protoc's conventions.
3. Generated identifiers derived from BAML source names are spelled exactly as the BAML author wrote them, never re-cased (SleepMs stays SleepMs). Suffixes the generator adds are snake and follow the other bridges: the async sibling of SleepMs is SleepMs_async (python parity), the opts struct for probe is probe_opts, setters are set_<param>.

Deliberate deviations from the Google guide

• Exceptions are used deliberately: the baml::error contract is the bridge's error surface. This is a knowing deviation from the Google guide's no-exceptions rule.
• Generated code approximates the layout (2-space indent) but is not clang-formatted.