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feat: New END_CPP11_EX() macro that allows parameterizing the return value - #6

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feat: New END_CPP11_EX() macro that allows parameterizing the return value#6
krlmlr wants to merge 12 commits into
f-end-cpp11-exfrom
claude/f-end-cpp11-ex-42ve6t

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@krlmlr krlmlr commented Aug 17, 2026

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Patch f-end-cpp11-ex of the stack.

END_CPP11 ends with a hard return R_NilValue;, so the BEGIN_CPP11 / END_CPP11 pair only wraps a function returning SEXP. A binding that returns anything else — a C-level callback with an int or a void* return, say — cannot use it, even though the unwind and error handling in between is exactly what it needs.

END_CPP11_EX(RET) is the same block with the return value as a parameter, and END_CPP11 becomes END_CPP11_EX(R_NilValue). Existing code is unaffected: the macro it expands to is byte-identical to what it was.

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https://claude.ai/code/session_01K8MneV8KqHYUuC8fWV3X5Q


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DavisVaughan and others added 12 commits April 3, 2026 13:09
* Don't rely on transitive include of `"fmt/core.h"`

We got it through `cpp11/protect.hpp`, but we should not rely on that

* Correctly use `fmt::runtime()` on runtime strings passed to `fmt::format()`

In fmt, there is a `FMT_CONSTEVAL` macro that resolves to `consteval` on "new enough" C++ (otherwise it doesn't do anything). For R 4.6+, the default C++ used is finally "new enough" (`__cplusplus > 201703L`).

This causes all `fmt::format()` calls to require a constant expression for `const char*` and `std::string&` input, which we are not currently doing via `fmt_arg`.

We have a runtime provided string, which must now be wrapped in `fmt::runtime()`, which is what we should have been doing all along.

* Add `r_ns_env()` and use in `get_namespace()`

Throwing an informative (and tested!) error when we can't find the package namespace

* Define `RCPP_NO_R_HEADERS_CHECK` before all `#include <Rcpp.h>` usage

`#include <cpp11/R.hpp>` sets everything up the right way, and otherwise we get a warning from Rcpp which doesn't seem to end up being relevant for this use case

* Use `r_env_has()` + `r_env_get()`

To avoid triggering a NOTE about usage of `Rf_findVarInFrame3()` on R 4.5, where technically we had the tools to avoid that
* Teach `cpp_source()` how to source multiple files

* NEWS bullet

* Link to PR
…violations (r-lib#493)

* Add failing test

* Use tag types to generate attribute specific internals

* NEWS bullet

* Formatting
* Update `cran-comments.md`

* Increment version number to 0.5.5
@krlmlr
krlmlr changed the base branch from main to f-end-cpp11-ex August 17, 2026 21:14
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