Feature/use modules by ClausKlein · Pull Request #10 · bemanproject/monadics

ClausKlein · 2026-03-13T13:52:19Z

This is only a prove of concept to build an interface library (header only) and a c++20 module library together

IMHO you should not realy need 2 module libs
the beman library naming convention is no clear to me. The install function does only yet accepts beman.xxx_yyy names
some historic toolchains should not used with c++26 on CI
g++-15 with CXX_MODULES does not compile friends #15
CI build with and w/o module with MSVC and clang++-22
All test on CI with and w/o modules
Supports usable installation too

msvetkin · 2026-03-13T22:17:48Z

+    set_target_properties(
+        beman.monadics.examples.${example}
+        PROPERTIES
+            # TODO(CK): why? CXX_EXTENSIONS OFF


I don't think we actually need to do that per target. I was just following recommendations.
I think it should be controlled by a consumer.

I have not verified if it is okay to mix for example consumer build with -std=gnu++20 and library has been builded with std=c++20

you can't mix any compile flag or option, still a cmake constrain!

msvetkin · 2026-03-13T22:28:01Z

+        "BEMAN_USE_MODULES": true,
+        "BEMAN_USE_STD_MODULE": true,
+        "CMAKE_CXX_STANDARD": "23",


I have mostly testing by default with C++20 and modules should be a separate preset.
Maybe we could use somehow environment variables to conditionally extend preset?

this can be controlled like here:

https://github.com/ClausKlein/asio/blob/feature/module/.github/workflows/clang.yml

@ednolan but not with beman CI workflows?

msvetkin · 2026-03-13T22:29:00Z

+      "environment": {
+        "CXX": "clang++",
+        "CMAKE_CXX_FLAGS": "-stdlib=libc++"


That comes from toolchain.

On OSX it is still needed!

msvetkin · 2026-03-13T22:29:06Z

+        "CXX": "clang++",
+        "CMAKE_CXX_FLAGS": "-stdlib=libc++"


msvetkin · 2026-03-13T22:31:28Z


 if(BEMAN_USE_MODULES)
-    add_library(beman.monadics.detail)
+    add_library(beman.monadics_detail)


I thought we are using . every as a separator or does it make any difference?

@ednolan The beman install script has some checks to force this!

msvetkin · 2026-03-13T22:35:23Z

+endif()

-beman_install_library(beman.monadics)
+beman_install_library(beman.monadics TARGETS beman.monadics beman.monadics_detail beman.monadics_module)


Hm... I am not sure I have understood why do we need all 3 targets.
If the library configured with BEMAN_USE_MODULES then we should not leak any details to a consumer, so we should not install beman.monadics_detail.

cmake needs all headers and modules to build the BMI again for a consumer!

Right, that is the case when library installed as system library.

ClausKlein · 2026-03-14T08:45:38Z

FYI:

bash-5.3$ clang-tidy examples/monadics_std_usage.cpp 
949 warnings generated.
/Users/clausklein/Workspace/cpp/beman-project/monadics/examples/monadics_std_usage.cpp:10:19: warning: function 'error' has inline specifier but is implicitly inlined [readability-redundant-inline-specifier]
   10 |     [[nodiscard]] inline static constexpr auto error() noexcept { return std::nullopt; }
      |                   ^~~~~~
Suppressed 948 warnings (948 in non-user code).
Use -header-filter=.* or leave it as default to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
bash-5.3$

Please check witch clang and w/o module:

run-clang-tidy -checks='-*,misc-include-*' tests/beman/monadics

ClausKlein · 2026-03-14T09:25:39Z

FIXME: the usage of this header is strange and fragile!

bash-5.3$ git ls-files ::*trait.hpp
tests/beman/monadics/enum/trait.hpp
tests/beman/monadics/expected/trait.hpp
tests/beman/monadics/optional/trait.hpp
tests/beman/monadics/raw_ptr/trait.hpp
tests/beman/monadics/shared_ptr/trait.hpp
bash-5.3$ 

bash-5.3$ head `git ls-files ::*trait.hpp`
==> tests/beman/monadics/enum/trait.hpp <==
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef BEMAN_MONADICS_RAW_PTR_TRAIT_HPP
#define BEMAN_MONADICS_RAW_PTR_TRAIT_HPP

#include <beman/monadics/monadics.hpp>

#include <concepts>
#include <utility>


==> tests/beman/monadics/expected/trait.hpp <==
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef BEMAN_MONADICS_EXPECTED_TRAIT_HPP
#define BEMAN_MONADICS_EXPECTED_TRAIT_HPP

#include <beman/monadics/monadics.hpp>

#include <type_traits>
#include <utility>
#include <concepts>

==> tests/beman/monadics/optional/trait.hpp <==
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef BEMAN_MONADICS_OPTIONAL_TRAIT_HPP
#define BEMAN_MONADICS_OPTIONAL_TRAIT_HPP

#include <beman/monadics/monadics.hpp>

#include <optional>

template <typename T>

==> tests/beman/monadics/raw_ptr/trait.hpp <==
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef BEMAN_MONADICS_RAW_PTR_TRAIT_HPP
#define BEMAN_MONADICS_RAW_PTR_TRAIT_HPP

#include <beman/monadics/monadics.hpp>

#include <type_traits>

template <typename Box>

==> tests/beman/monadics/shared_ptr/trait.hpp <==
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef BEMAN_MONADICS_OPTIONAL_TRAIT_HPP
#define BEMAN_MONADICS_OPTIONAL_TRAIT_HPP

#include <beman/monadics/monadics.hpp>

#include <memory>
#include <utility>

bash-5.3$

ClausKlein · 2026-03-14T15:48:11Z

        "_debug-base"
      ],
      "cacheVariables": {
+        "BEMAN_USE_MODULES": false,


Disabled for now, it does not compile with g++-15

ClausKlein · 2026-03-14T15:48:58Z

        "_release-base"
      ],
      "cacheVariables": {
+        "BEMAN_USE_MODULES": false,


Disabled for now, it does not compile with g++-15

coveralls · 2026-03-15T10:55:55Z

coverage: 100.0%. remained the same
when pulling 90d9241 on feature/use-modules
into 96a3721 on main.

Replace global CMAKE_CXX_STANDARD with target_compile_features. Using target_compile_features expresses the language requirement as a target usage requirement, ensuring correct propagation to dependents. Disable compiler extensions to enforce strict ISO C++20 and avoid compiler-specific behavior.

Ensure they are built with strict ISO C++ and behave consistently with the main library.

Enforce stricter builds to catch issues early.

ClausKlein requested review from JeffGarland, ednolan and msvetkin as code owners March 13, 2026 13:52

ClausKlein marked this pull request as draft March 13, 2026 13:52

ClausKlein self-assigned this Mar 13, 2026

ClausKlein marked this pull request as ready for review March 13, 2026 13:57

ClausKlein marked this pull request as draft March 13, 2026 15:57

ClausKlein force-pushed the feature/use-modules branch from 97f42f3 to a8de9f8 Compare March 13, 2026 20:47

ClausKlein marked this pull request as ready for review March 13, 2026 20:48

msvetkin reviewed Mar 13, 2026

View reviewed changes

ClausKlein force-pushed the feature/use-modules branch from 2b53237 to 81be02e Compare March 14, 2026 15:36

ClausKlein commented Mar 14, 2026

View reviewed changes

ClausKlein mentioned this pull request Mar 14, 2026

cant compile due to catch2 cmake issue #13

Closed

ClausKlein force-pushed the feature/use-modules branch from 6321b93 to 5c15262 Compare March 15, 2026 10:53

msvetkin and others added 12 commits March 18, 2026 17:11

refactor(cmake): disable C++ extensions for tests

6cc94d7

Ensure they are built with strict ISO C++ and behave consistently with the main library.

build(cmake): enable compile and link warnings as errors

6a1fe84

Enforce stricter builds to catch issues early.

refactor(tests): reorder includes and remove redundant detail includes

f120208

refactor(cmake): move library target definition from include/ to src/

071114e

feat(modules): add module compatibility guards to all detail headers

03c176b

feat(modules): add C++20 module interface files

bbf7b80

feat(cmake): add BEMAN_USE_MODULES option and module build support

855faa0

Add header only library too

b421385

Add instal rules

70d1177

Use module from preset if possible

4a6ab24

Quickfix

16014d2

ClausKlein added 8 commits March 18, 2026 17:11

Upgrade to Catch2 v3.13.0

1bd300c

Fix format after rebase

65d8ea5

Fix errors after rebase

5922698

Suppress Warning C5244 for MSVC

1a65104

Add missing includes

56f0d70

Try to fix clang-tidy warnings misc-include-*

ff6350c

Sort and indent includes

7817b36

Add round trip test too

2880561

ClausKlein force-pushed the feature/use-modules branch from 5c15262 to 2880561 Compare March 18, 2026 16:15

beman-submodule update

c7b6fd6

ClausKlein requested a review from msvetkin March 18, 2026 16:44

ClausKlein added 2 commits March 19, 2026 11:20

First test with cmake v4.3

6bbc4e8

Try CPOs to prevent friends

90d9241

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FIXME: the usage of this header is strange and fragile!

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