Implement m-variables

The m-variables provide the same functionality as their
template metaprogramming-based version by using macros. This
new implementation ensures considerably faster compile times.

.clang-format

@@ -0,0 +1,87 @@
+---
+Language:        Cpp
+# BasedOnStyle:  Google
+AccessModifierOffset: -2
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: true
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlinesLeft: true
+AlignOperands:   true
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: true
+AllowShortLoopsOnASingleLine: true
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakBeforeMultilineStrings: true
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: false
+BinPackParameters: false
+BraceWrapping:  
+  AfterClass:      false
+  AfterControlStatement: false
+  AfterEnum:       false
+  AfterFunction:   false
+  AfterNamespace:  false
+  AfterObjCDeclaration: false
+  AfterStruct:     false
+  AfterUnion:      false
+  BeforeCatch:     false
+  BeforeElse:      false
+  IndentBraces:    false
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Attach
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: false
+ColumnLimit:     100
+CommentPragmas:  '(.+\n*.+)*'
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+ExperimentalAutoDetectBinPacking: false
+ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH ]
+IncludeCategories:
+  - Regex:           '^<.*\.h>'
+    Priority:        2
+  - Regex:           '^<.*'
+    Priority:        1
+  - Regex:           '.*'
+    Priority:        3
+IndentCaseLabels: true
+IndentWidth:     4
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: true
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+ObjCBlockIndentWidth: 2
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: false
+PenaltyBreakBeforeFirstCallParameter: 1
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 200
+SortIncludes:    true
+PointerAlignment: Left
+SpaceAfterCStyleCast: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 2
+SpacesInAngles:  false
+SpacesInContainerLiterals: true
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard:        Auto
+TabWidth:        4
+UseTab:          Never
+...

.github/workflows/ungar-ci.yml

@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+env:
+  BUILD_TYPE: Release
+
+jobs:
+  ci:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ ubuntu-latest ]
+        compiler: [ gcc-11, gcc-13 ]
+
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Check out Ungar
+      uses: actions/checkout@v3
+
+    - name: Install compiler 
+      id: install_compiler
+      uses: rlalik/setup-cpp-compiler@v1.2
+      with:
+        compiler: ${{ matrix.compiler }}
+
+    - name: Configure CMake
+      run: cmake -DUNGAR_BUILD_TESTS=ON
+           -DUNGAR_BUILD_EXAMPLES=ON
+           -DUNGAR_ENABLE_LOGGING=ON
+           -DUNGAR_ENABLE_AUTODIFF=ON
+           -DUNGAR_ENABLE_OPTIMIZATION=ON
+           -B ${{github.workspace}}/build
+           -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+           -DCMAKE_C_COMPILER=${{ steps.install_compiler.outputs.cc }}
+           -DCMAKE_CXX_COMPILER=${{ steps.install_compiler.outputs.cxx }}
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
+
+    - name: Test
+      working-directory: ${{github.workspace}}/build
+      run: ctest -C ${{env.BUILD_TYPE}}

.gitignore

@@ -0,0 +1,2 @@
+/build/
+/.cache/

CMakeLists.txt

@@ -0,0 +1,174 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(Ungar VERSION 1.0.1)
+
+add_library(ungar INTERFACE)
+add_library(ungar::ungar ALIAS ungar)
+target_compile_features(ungar INTERFACE cxx_std_20)
+
+# ##############################################################################
+# Set up CMake options.
+# ##############################################################################
+include(CMakeDependentOption)
+
+option(
+  UNGAR_USE_SYSTEM_LIBRARIES
+  "Prevent automatic download of missing external dependencies. To selectively use system-wide packages, provide their installation prefixes as CMake variables of the form '<PackageName>_ROOT', where <PackageName> is the (case-preserved) name given to the find_package() call and _ROOT is literal."
+  OFF)
+option(UNGAR_BUILD_TESTS "Add targets for unit testing." OFF)
+option(UNGAR_BUILD_EXAMPLES "Add targets showing Ungar's features." OFF)
+option(UNGAR_INSTALL "Install CMake targets during install step." OFF)
+option(UNGAR_ENABLE_OPTIMIZATION
+       "Enable Ungar's nonlinear programming interface." OFF)
+cmake_dependent_option(
+  UNGAR_ENABLE_LOGGING
+  "Enable Ungar's logging functionalities. Automatically enabled if any of the flags 'UNGAR_ENABLE_AUTODIFF', 'UNGAR_ENABLE_OPTIMIZATION', and 'UNGAR_BUILD_EXAMPLES' is set to 'ON'."
+  OFF
+  "NOT UNGAR_ENABLE_AUTODIFF;NOT UNGAR_ENABLE_OPTIMIZATION;NOT UNGAR_BUILD_EXAMPLES"
+  ON)
+cmake_dependent_option(
+  UNGAR_ENABLE_AUTODIFF
+  "Enable Ungar's autodiff interface. Automatically enabled if 'UNGAR_ENABLE_OPTIMIZATION' is set to 'ON'."
+  OFF
+  "NOT UNGAR_ENABLE_OPTIMIZATION"
+  ON)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+message(STATUS "--------------------------------------------------")
+message(STATUS "Configuring Ungar with the following options:")
+message(STATUS "    Enable logging         : ${UNGAR_ENABLE_LOGGING}")
+message(STATUS "    Enable autodiff        : ${UNGAR_ENABLE_AUTODIFF}")
+message(STATUS "    Enable optimization    : ${UNGAR_ENABLE_OPTIMIZATION}")
+message(STATUS "    Build examples         : ${UNGAR_BUILD_EXAMPLES}")
+message(STATUS "    Build tests            : ${UNGAR_BUILD_TESTS}")
+message(STATUS "    Install                : ${UNGAR_INSTALL}")
+message(STATUS "    Use system libraries   : ${UNGAR_USE_SYSTEM_LIBRARIES}")
+
+# Add external dependencies.
+set_property(GLOBAL PROPERTY CTEST_TARGETS_ADDED 1)
+add_subdirectory(external)
+message(STATUS "--------------------------------------------------")
+
+# ##############################################################################
+# Add compile options.
+# ##############################################################################
+if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang") # Clang.
+  target_compile_options(ungar INTERFACE "-pedantic" "$<$<CONFIG:RELEASE>:-O2>")
+elseif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU") # GNU Compiler Collection (GCC).
+  target_compile_options(
+    ungar
+    INTERFACE "-pedantic"
+              "-ftemplate-backtrace-limit=1"
+              "-fconstexpr-depth=2147483647"
+              "-fconstexpr-loop-limit=2147483647"
+              "-fconstexpr-cache-depth=2147483647"
+              "-fconstexpr-ops-limit=2147483647"
+              "$<$<CONFIG:RELEASE>:-O3>")
+elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Intel") # Intel C++ Compiler.
+  message(WARNING "Intel C++ Compiler is not supported.")
+elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC") # MSVC.
+  target_compile_options(ungar INTERFACE "/W4" "$<$<CONFIG:RELEASE>:/O2>")
+else()
+  message(WARNING "${CMAKE_CXX_COMPILER_ID} is not supported.")
+endif()
+
+# ##############################################################################
+# Set Ungar's include directories and link libraries.
+# ##############################################################################
+# Core modules.
+list(APPEND UNGAR_INCLUDE_DIRECTORIES
+     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+     $<INSTALL_INTERFACE:include>)
+list(APPEND UNGAR_LINK_LIBRARIES Eigen3::Eigen hana Boost::preprocessor)
+
+# Optional modules.
+if(UNGAR_ENABLE_LOGGING)
+  list(APPEND UNGAR_LINK_LIBRARIES spdlog::spdlog)
+endif()
+if(UNGAR_ENABLE_AUTODIFF)
+  list(APPEND UNGAR_LINK_LIBRARIES CppAD::CppAD CppADCodeGen::CppADCodeGen
+       ${CMAKE_DL_LIBS} finitediff::finitediff)
+endif()
+if(UNGAR_ENABLE_OPTIMIZATION)
+  list(APPEND UNGAR_LINK_LIBRARIES osqp-cpp::osqp-cpp)
+endif()
+
+target_include_directories(ungar INTERFACE ${UNGAR_INCLUDE_DIRECTORIES})
+target_link_libraries(ungar INTERFACE ${UNGAR_LINK_LIBRARIES})
+
+# ##############################################################################
+# Set Ungar's compile definitions.
+# ##############################################################################
+target_compile_definitions(
+  ungar
+  INTERFACE $<$<CONFIG:Debug>:_GLIBCXX_ASSERTIONS>
+            $<$<CONFIG:RelWithDebInfo>:_GLIBCXX_ASSERTIONS>
+            $<$<CONFIG:MinSizeRel>:UNGAR_CONFIG_ENABLE_RELEASE_MODE>
+            $<$<CONFIG:Release>:UNGAR_CONFIG_ENABLE_RELEASE_MODE>)
+
+if(UNGAR_ENABLE_LOGGING)
+  target_compile_definitions(ungar INTERFACE -DUNGAR_CONFIG_ENABLE_LOGGING)
+endif()
+
+if(UNGAR_ENABLE_AUTODIFF)
+  target_compile_definitions(
+    ungar
+    INTERFACE -DUNGAR_CONFIG_ENABLE_AUTODIFF
+    INTERFACE "UNGAR_CODEGEN_FOLDER=\"${CMAKE_BINARY_DIR}/ungar_codegen\"")
+endif()
+
+if(UNGAR_ENABLE_OPTIMIZATION)
+  target_compile_definitions(ungar INTERFACE -DUNGAR_CONFIG_ENABLE_OPTIMIZATION)
+endif()
+
+# ##############################################################################
+# Add optional targets.
+# ##############################################################################
+if(UNGAR_BUILD_TESTS)
+  enable_testing()
+  add_subdirectory(test)
+endif()
+
+if(UNGAR_BUILD_EXAMPLES)
+  add_subdirectory(example)
+endif()
+
+if(UNGAR_INSTALL)
+  include(GNUInstallDirs)
+
+  # Install Ungar headers.
+  install(DIRECTORY include/ DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+
+  # Install Ungar binaries.
+  install(
+    TARGETS ungar
+    EXPORT ${PROJECT_NAME}Targets
+    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+    ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+    INCLUDES
+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+
+  # Install Ungar configuration files.
+  include(CMakePackageConfigHelpers)
+
+  configure_package_config_file(
+    UngarConfig.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
+    INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ungar)
+
+  write_basic_package_version_file(
+    ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
+    VERSION ${PACKAGE_VERSION}
+    COMPATIBILITY SameMajorVersion)
+  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
+                ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
+          DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ungar)
+
+  # Perform installation.
+  install(
+    EXPORT ${PROJECT_NAME}Targets
+    FILE ${PROJECT_NAME}Targets.cmake
+    NAMESPACE ungar::
+    DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ungar)
+endif(UNGAR_INSTALL)