Add nested src/CMakeLists.txt with sas_core_pure library + fix Docker compose

[mmmarinho]

This PR introduces two improvements:

1. Nested src/CMakeLists.txt with sas_core_pure library

All C++ sources in src/ are now built via add_subdirectory(src) into a static library target sas_core_pure. This library contains all non-ROS2 C++ code:

• sas_clock.cpp, sas_core.cpp, sas_object.cpp, sas_shutdown_signaler.cpp
• sas_robot_driver.cpp, examples/sas_robot_driver_example.cpp
• eigen3_std_conversions.cpp

The parent CMakeLists.txt creates an INTERFACE alias sas_core that transitively links to sas_core_pure, so external ROS packages that depend on sas_core continue to work unchanged.

2. Fix docker/compose.yml for container environments

The original bind mount (../../sas_core:/root/sas_core_devel/src/sas_core) fails when Docker Desktop cannot access the container's internal filesystem. Replaced with COPY in the Dockerfile so the source is baked into the image at build time. All 6 ROS2 examples (C++ and Python) build and run successfully.

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This PR was created by an AI agent (OpenHands) on behalf of the user.

[mmmarinho]

CMake refactoring: sas_core_pure moved to cmake/sas_core_pure.cmake

What changed:

• Relocated the nested src/CMakeLists.txt to cmake/sas_core_pure.cmake in the repository root
• Parent CMakeLists.txt now uses include(cmake/sas_core_pure.cmake) instead of add_subdirectory(src)
• All paths in the .cmake file use CMAKE_CURRENT_LIST_DIR to correctly resolve relative paths when included (rather than CMAKE_CURRENT_SOURCE_DIR)

Additional fixes in this commit:

• Fixed test_consumer to link against sas_core::sas_core_pure (the exported namespaced target)
• Fixed Docker COPY command to include full build context

Docker Compose builds both packages and runs all examples + test_consumer successfully.

Commented by an AI agent (OpenHands) on behalf of the user.

[mmmarinho]

CMake restructuring: cpplib.cmake, pythonlib.cmake, and ROS2_BUILD option

What changed:

1. Renamed cmake/sas_core_pure.cmake to cmake/cpplib.cmake

• Cleaner name reflecting it is the platform-independent C++ library.

2. Extracted Python wrapper into cmake/pythonlib.cmake

• Moved pybind11 setup and _sas_core module build from the parent CMakeLists.txt into its own included module.
• Install path adapts automatically: uses ament PYTHON_INSTALL_DIR when ROS2_BUILD=ON, falls back to standard Python site-packages otherwise.

3. Added ROS2_BUILD CMake option (default: ON)

• Parent CMakeLists.txt now has option(ROS2_BUILD ...) — when disabled, only the pure C++ library (cpplib.cmake) and Python bindings (pythonlib.cmake) are built.
• The ROS2-specific section (ament exports, example executables, ament_package()) is gated behind if(ROS2_BUILD).
• This enables consuming sas_core_pure from non-ROS2 CMake projects via include(cmake/cpplib.cmake).

Docker Compose continues to build both packages (sas_core + test_consumer) and run all examples successfully.

Commented by an AI agent (OpenHands) on behalf of the user.

[mmmarinho]

Python import tests and standalone non-ROS2 CMake test package

test_consumer Python import test

• Added test_consumer/test/test_python_import.py that imports Clock, Statistics, RobotDriver, and ShutdownSignaler from sas_core to verify the Python bindings work from a downstream ROS2 package.
• Updated test_consumer/CMakeLists.txt to register the test via add_test().

standalone_consumer -- non-ROS2 CMake test package

• New standalone_consumer/ directory: a plain CMake project (no package.xml, no ament) that validates cpplib.cmake and pythonlib.cmake can be included and used outside of ROS2.
• CMakeLists.txt sets SAS_CORE_SOURCE_DIR to locate the sas_core cmake modules, then includes cpplib.cmake and pythonlib.cmake.
• src/standalone_consumer.cpp links against sas_core_pure and exercises sas::concatenate, sas::incremental_mean, and ShutdownSignaler.
• test/test_python_import.py verifies the Python bindings import from the non-ROS2 build.
• Docker Compose builds this with plain cmake/make (outside the colcon workspace) and runs both the C++ binary and the Python test.

Fixes in pythonlib.cmake

• Module name is now always _sas_core (not _PROJECT_NAME) so the import works regardless of which project includes pythonlib.cmake.
• add_subdirectory() now provides an explicit binary directory to support out-of-tree includes.

All four test stages pass in Docker Compose:

1. ROS2 examples (C++ + Python) from sas_core
2. test_consumer C++ binary
3. test_consumer Python import test
4. standalone_consumer C++ binary + Python import test (no ROS2)

Commented by an AI agent (OpenHands) on behalf of the user.

[mmmarinho]

Originally intended files are ok, but the tests need to be better organized if added in this PR. Maybe better to leave it for another one.

[mmmarinho]

Simplified CMake per best practices and removed temporary test packages

Removed

• test_consumer/ and standalone_consumer/ -- these were temporary validation packages used to verify the refactored CMake structure works. They are no longer needed in the PR.
• Dockerfile and compose.yml references to those packages.

CMake simplifications

cpplib.cmake

• Switched to target_sources() instead of inline source list in add_library() (modern CMake convention).
• Removed redundant temporary variables.

pythonlib.cmake

• Hardcoded module name as _sas_core directly (removed indirection variable).
• Cleaned up install path logic and removed verbose comment blocks.

root CMakeLists.txt

• Added foreach(IN ITEMS ...) loop for example executables to reduce boilerplate.
• Removed duplicate find\_package(Eigen3) from root (only needed in cpplib.cmake where it is a dependency).
• Removed redundant ament\_export\_include\_directories() -- target exports already propagate include directories.
• Cleaned up section headers.

All 6 targets build and run correctly in Docker Compose (sas_core_pure, _sas_core, sas_core_example, sas_clock_example, sas_clock_sched_fifo_example, sas_robot_driver_example).

_Commented by an AI agent (OpenHands) on behalf of the user._

[mmmarinho]

Added a Using as a non-ROS2 dependency section to README.md with a FetchContent example, the -DROS2_BUILD=OFF flag, and the Eigen3/dqrobotics dependency note.

Commented by an AI agent (OpenHands) on behalf of the user.

[mmmarinho]

Updated the FetchContent example:

• Set GIT_TAG to jazzy (the stable branch) instead of the placeholder
• Added set(ROS2_BUILD OFF CACHE BOOL FORCE) before FetchContent_MakeAvailable so the non-ROS2 build works from within the CMake file itself (verified against the official CMake FetchContent docs -- pre-set cache values are respected by option()).

Commented by an AI agent (OpenHands) on behalf of the user.