add CPM_SOURCE_ROOT option (#81)

* add CPM_SOURCE_ROOT option

* update version and readme

.gitignore

@@ -8,3 +8,5 @@ install_manifest.txt
 compile_commands.json
 CTestTestfile.cmake
 build
+.vscode
+.DS_Store

.travis.yml

@@ -44,5 +44,9 @@ before_install:
   - cmake --version
 
 script:
+  # unit tests
+  - cmake -Htest -Bbuild/test
+  - CTEST_OUTPUT_ON_FAILURE=1 cmake --build build/test --target test
+  # examples
   - python3 examples/run_all.py
  

README.md

@@ -1,23 +1,29 @@
 [![Build Status](https://travis-ci.com/TheLartians/CPM.svg?branch=master)](https://travis-ci.com/TheLartians/CPM)
 
-# CPM
+<p align="center">
+  <img src="./logo/CPM.png" height="100" />
+</p>
 
-CPM is a CMake script that adds dependency management capabilities to CMake. 
-It's built as an extension of CMake's [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html) module that adds version control and simpler usage.
+# Setup-free CMake dependency management
 
-## Supported projects
+CPM is a CMake script that adds dependency management capabilities to CMake.
+It's built as a wrapper around CMake's [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html) module that adds version control and a simple API.
 
-Any project that you can add via `add_subdirectory` should already work with CPM.
+## Manage everything
+
+Anything can be added as a version-controlled dependency though CPM, no packaging required.
+Projects using CMake are automatically configured and their targets can be used immediately.
+For everything else, a target can be created manually (see below).
 
 ## Usage
 
-After `CPM.cmake` has been added to your project, the function `CPMAddPackage` can be used to fetch and configure all dependencies.
-Afterwards all targets defined in the dependencies can be used.
-`CPMAddPackage` takes the following named arguments.
+After `CPM.cmake` has been [added](#adding-cpm) to your project, the function `CPMAddPackage` can be used to fetch and configure a dependency.
+Afterwards, any targets defined in the dependency can be used directly.
+`CPMAddPackage` takes the following named parameters.
 
 ```cmake
 CPMAddPackage(
-  NAME          # The name of the dependency (should be chosen to match the main target's name)
+  NAME          # The unique name of the dependency (should be the main target's name)
   VERSION       # The minimum version of the dependency (optional, defaults to 0)
   OPTIONS       # Configuration options passed to the dependency (optional)
   DOWNLOAD_ONLY # If set, the project is downloaded, but not configured (optional)
@@ -25,9 +31,9 @@ CPMAddPackage(
 )
 ```
 
-The origin is usually specified by a `GIT_REPOSITORY`, but [svn revisions and direct URLs are also supported](https://cmake.org/cmake/help/latest/module/FetchContent.html#declaring-content-details).
-If `GIT_TAG` hasn't been explicitly specified it defaults to `v(VERSION)`, a common convention for github projects.
-`GIT_TAG` can also be set to a branch name such as `master` to download the most recent version.
+The origin may be specified by a `GIT_REPOSITORY`, but other sources, such as direct URLs, are [also supported](https://cmake.org/cmake/help/v3.11/module/ExternalProject.html#external-project-definition).
+If `GIT_TAG` hasn't been explicitly specified it defaults to `v(VERSION)`, a common convention for git projects.
+`GIT_TAG` can also be set to a specific commit or a branch name such as `master` to download the most recent version.
 
 Besides downloading and to configuring the dependency, the following variables are defined in the local scope, where `(DEPENDENCY)` is the name of the dependency.
 
@@ -35,7 +41,7 @@ Besides downloading and to configuring the dependency, the following variables a
 - `(DEPENDENCY)_BINARY_DIR` is the path to the build directory of the dependency.
 - `(DEPENDENCY)_ADDED` is set to `YES` if the dependency has not been added before, otherwise it is set to `NO`.
 
-## Full Example
+## Full CMakeLists Example
 
 ```cmake
 cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
@@ -43,6 +49,10 @@ cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 # create project
 project(MyProject)
 
+# add executable
+add_executable(myProject myProject.cpp)
+set_target_properties(myProject PROPERTIES CXX_STANDARD 17)
+
 # add dependencies
 include(cmake/CPM.cmake)
 
@@ -54,9 +64,6 @@ CPMAddPackage(
     "LARS_PARSER_BUILD_GLUE_EXTENSION ON"
 )
 
-# add executable
-add_executable(myProject myProject.cpp)
-set_target_properties(myProject PROPERTIES CXX_STANDARD 17)
 target_link_libraries(myProject LarsParser)
 ```
 
@@ -67,20 +74,52 @@ See the [examples directory](https://github.com/TheLartians/CPM/tree/master/exam
 To add CPM to your current project, simply add `cmake/CPM.cmake` to your project's `cmake` directory. The command below will perform this automatically.
 
 ```bash
+mkdir -p cmake
 wget -O cmake/CPM.cmake https://raw.githubusercontent.com/TheLartians/CPM/master/cmake/CPM.cmake
 ```
 
+You can also use CMake to download CPM for you. See the [wiki](https://github.com/TheLartians/CPM/wiki/Adding-CPM) for more details.
+
 ## Updating CPM
 
 To update CPM to the newest version, simply update the script in the project's cmake directory, for example by running the command above. Dependencies using CPM will automatically use the updated script of the outermost project.
 
-## Snipplets
+## Advantages
+
+- **Small and reusable projects** CPM takes care of all project dependencies, allowing developers to focus on creating small, well-tested frameworks.
+- **Cross-Platform** CPM adds projects via `add_subdirectory`, which is compatible with all cmake toolchains and generators.
+- **Reproducable builds** By using versioning via git tags it is ensured that a project will always be in the same state everywhere.
+- **Recursive dependencies** Ensures that no dependency is added twice and is added in the minimum required version.
+- **Plug-and-play** No need to install anything. Just add the script to your project and you're good to go.
+- **No packaging required** There is a good chance your existing projects already work as CPM dependencies.
+- **Simple source distribution** CPM makes including projects with source files and dependencies easy, reducing the need for monolithic header files.
+
+## Limitations
+
+- **No pre-built binaries** For every new project, all dependencies must be downloaded and built from scratch. A possible workaround is to use CPM to fetch a pre-built binary or to enable local packages (see [below](#local-packages)).
+- **Dependent on good CMakeLists** Many libraries do not have CMakeLists that work well for subprojects. Luckily this is slowly changing, however, until then, some manual configuration may be required (see the snippets [below](#snippets)). For best practices on preparing your projects for CPM, see the [wiki](https://github.com/TheLartians/CPM/wiki/Preparing-projects-for-CPM). 
+- **First version used** In diamond-shaped dependency graphs (e.g. `A` depends on `C`@1.1 and `B`, which itself depends on `C`@1.2 the first added dependency will be used (in this case `C`@1.1). In this case, B requires a newer version of `C` than `A`, so CPM will emit an error. This can be resolved by updating the outermost dependency version.
+
+For projects with more complex needs and where an extra setup step doesn't matter, it is worth to check out fully featured C++ package managers such as [conan](https://conan.io), [vcpkg](https://github.com/microsoft/vcpkg) or [hunter](https://github.com/ruslo/hunter).
+Support for package managers is also [planned](https://github.com/TheLartians/CPM/issues/51) for a future version of CPM.
+
+## Options
+
+### CPM_SOURCE_ROOT
+
+To avoid re-downloading dependencies, configure the project with the cmake option `-DCPM_SOURCE_ROOT=<path to an external download directory>`.
+
+### CPM_USE_LOCAL_PACKAGES
+
+CPM can be configured to use `find_package` to search for locally installed dependencies first by setting the CMake option `CPM_USE_LOCAL_PACKAGES`.
+If the option `CPM_LOCAL_PACKAGES_ONLY` is set, CPM will emit an error if the dependency is not found locally.
+
+## Snippets
 
 These examples demonstrate how to include some well-known projects with CPM.
+See the [wiki](https://github.com/TheLartians/CPM/wiki/More-Snippets) for more snippets.
 
-### [Catch2](https://github.com/catchorg/Catch2.git)
-
-Has a CMakeLists.txt that supports `add_subdirectory`.
+### [Catch2](https://github.com/catchorg/Catch2)
 
 ```cmake
 CPMAddPackage(
@@ -90,12 +129,47 @@ CPMAddPackage(
 )
 ```
 
-See [here](https://github.com/TheLartians/CPM/blob/master/examples/doctest/CMakeLists.txt) for doctest example.
-Note that we can shorten Github and Gitlab URLs by using `GITHUB_REPOSITORY` or `GITLAB_REPOSITORY`, respectively.
+### [Boost (via boost-cmake)](https://github.com/Orphis/boost-cmake)
 
-### [google/benchmark](https://github.com/google/benchmark.git)
+```CMake
+CPMAddPackage(
+  NAME boost-cmake
+  GITHUB_REPOSITORY Orphis/boost-cmake
+  VERSION 1.67.0
+)
+```
 
-Has a CMakeLists.txt that supports `add_subdirectory`, but needs some configuring to work without external dependencies.
+### [cxxopts](https://github.com/jarro2783/cxxopts)
+
+```cmake
+CPMAddPackage(
+  NAME cxxopts
+  GITHUB_REPOSITORY jarro2783/cxxopts
+  VERSION 2.2.0
+  OPTIONS
+    "CXXOPTS_BUILD_EXAMPLES Off"
+    "CXXOPTS_BUILD_TESTS Off"
+)
+```
+
+### [Yaml-cpp](https://github.com/jbeder/yaml-cpp)
+
+```CMake
+CPMAddPackage(
+  NAME yaml-cpp
+  GITHUB_REPOSITORY jbeder/yaml-cpp
+  # 0.6.2 uses depricated CMake syntax
+  VERSION 0.6.3
+  # 0.6.3 is not released yet, so use a recent commit
+  GIT_TAG 012269756149ae99745b6dafefd415843d7420bb 
+  OPTIONS
+    "YAML_CPP_BUILD_TESTS Off"
+    "YAML_CPP_BUILD_CONTRIB Off"
+    "YAML_CPP_BUILD_TOOLS Off"
+)
+```
+
+### [google/benchmark](https://github.com/google/benchmark)
 
 ```cmake
 CPMAddPackage(
@@ -106,44 +180,59 @@ CPMAddPackage(
     "BENCHMARK_ENABLE_TESTING Off"
 )
 
-# needed to compile with C++17
-set_target_properties(benchmark PROPERTIES CXX_STANDARD 17)
+if (benchmark_ADDED)
+  # compile with C++17
+  set_target_properties(benchmark PROPERTIES CXX_STANDARD 17)
+endif()
 ```
 
 ### [nlohmann/json](https://github.com/nlohmann/json)
 
-Header-only library with a huge git repositoy.
-Instead of downloading the whole repositoy, we fetch the zip included with the release and create our own target.
-
 ```cmake
 CPMAddPackage(
   NAME nlohmann_json
   VERSION 3.6.1  
+  # the git repo is incredibly large, so we download the archived include directory
   URL https://github.com/nlohmann/json/releases/download/v3.6.1/include.zip
   URL_HASH SHA256=69cc88207ce91347ea530b227ff0776db82dcb8de6704e1a3d74f4841bc651cf
 )
 
 if (nlohmann_json_ADDED)
-  add_library(nlohmann_json INTERFACE)
+  add_library(nlohmann_json INTERFACE IMPORTED)
   target_include_directories(nlohmann_json INTERFACE ${nlohmann_json_SOURCE_DIR})
 endif()
 ```
 
-Adding large repos works as well, but takes a while for the initial clone.
+### [Range-v3](https://github.com/ericniebler/range-v3)
+
+```Cmake
+CPMAddPackage(
+  NAME range-v3
+  URL https://github.com/ericniebler/range-v3/archive/0.5.0.zip
+  VERSION 0.5.0
+  # the range-v3 CMakeLists screws with configuration options
+  DOWNLOAD_ONLY True
+)
+
+if(range-v3_ADDED) 
+  add_library(range-v3 INTERFACE IMPORTED)
+  target_include_directories(range-v3 INTERFACE "${range-v3_SOURCE_DIR}/include")
+endif()
+```
 
 ### [Lua](https://www.lua.org)
 
-Lua does not oficially support CMake, so we query the sources and create our own target.
-
 ```cmake
 CPMAddPackage(
   NAME lua
   GIT_REPOSITORY https://github.com/lua/lua.git
-  VERSION 5-3-4
+  VERSION 5.3.5
   DOWNLOAD_ONLY YES
 )
 
 if (lua_ADDED)
+  # lua has no CMake support, so we create our own target
+
   FILE(GLOB lua_sources ${lua_SOURCE_DIR}/*.c)
   add_library(lua STATIC ${lua_sources})
 
@@ -154,25 +243,8 @@ if (lua_ADDED)
 endif()
 ```
 
-## Local packages
+For a full example on using CPM to download and configure lua with sol2 see [here](examples/sol2).
 
-CPM can be configured to use `find_package` to search for locally installed dependencies first.
-If `CPM_LOCAL_PACKAGES_ONLY` is set, CPM will error when dependency is not found locally.
+### Full Examples
 
-## Advantages
-
-- **Small and reusable projects** CPM takes care of project dependencies, allowing developers to focus on creating small, well-tested frameworks.
-- **Cross-Plattform** CPM adds projects via `add_subdirectory`, which is compatible with all cmake toolchains and generators.
-- **Reproducable builds** By using versioning via git tags it is ensured that a project will always be in the same state everywhere.
-- **Recursive dependencies** Ensures that no dependency is added twice and is added in the minimum required version.
-- **No installation required** No need to install anything. Just add the script to your project and you're good to go.
-- **No Setup required** There is a good chance your existing projects already work as CPM dependencies.
-- **Simple source distribution** CPM makes including projects with source files and dependencies easy, reducing the need for monolithic header files.
-
-## Limitations
-
-- **First version used** In diamond-shaped dependency graphs (e.g. `A` depends on `C`@1.1 and `B`, which itself depends on `C`@1.2 the first added dependency will be used (in this case `C`@1.1). In this case, B requires a newer version of `C` than `A`, so CPM will emit an error. This can be resolved by updating the outermost dependency version.
-- **No auto-update** To update a dependency, version must be adapted manually and there is no way for CPM to figure out the most recent version.
-- **No pre-built binaries** Unless they are installed or included in the linked repository. 
-
-For projects with more complex needs and where an extra setup step doesn't matter, it is worth to check out fully featured C++ package managers such as [conan](https://conan.io) or [hunter](https://github.com/ruslo/hunter).
+See the [examples directory](https://github.com/TheLartians/CPM/tree/master/examples) for full examples with source code.

cmake/CPM.cmake

@@ -28,7 +28,7 @@
 
 cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
 
-set(CURRENT_CPM_VERSION 0.11) 
+set(CURRENT_CPM_VERSION 0.13) 
 
 if(CPM_DIRECTORY)
   if(NOT ${CPM_DIRECTORY} MATCHES ${CMAKE_CURRENT_LIST_DIR})
@@ -42,9 +42,11 @@ endif()
 set(CPM_VERSION ${CURRENT_CPM_VERSION} CACHE INTERNAL "")
 set(CPM_DIRECTORY ${CMAKE_CURRENT_LIST_DIR} CACHE INTERNAL "")
 set(CPM_PACKAGES "" CACHE INTERNAL "")
+set(CPM_DRY_RUN OFF CACHE INTERNAL "Don't download or configure dependencies (for testing)")
 
 option(CPM_USE_LOCAL_PACKAGES "Use locally installed packages (find_package)" OFF)
 option(CPM_LOCAL_PACKAGES_ONLY "Use only locally installed packages" OFF)
+set(CPM_SOURCE_ROOT OFF CACHE PATH "Directory to downlaod CPM dependencies")
 
 include(FetchContent)
 include(CMakeParseArguments)
@@ -64,6 +66,7 @@ function(CPMAddPackage)
     DOWNLOAD_ONLY
     GITHUB_REPOSITORY
     GITLAB_REPOSITORY
+    SOURCE_DIR
   )
 
   set(multiValueArgs
@@ -89,14 +92,27 @@ function(CPMAddPackage)
     endif()
   endif()
 
-  if (NOT CPM_ARGS_VERSION)
-    set(CPM_ARGS_VERSION 0)
+  if (NOT DEFINED CPM_ARGS_VERSION)
+    if (DEFINED CPM_ARGS_GIT_TAG) 
+      CPM_GET_VERSION_FROM_GIT_TAG("${CPM_ARGS_GIT_TAG}" CPM_ARGS_VERSION)
+    endif()
+    if (NOT DEFINED CPM_ARGS_VERSION) 
+      set(CPM_ARGS_VERSION 0)
+    endif()
   endif()
 
-  if (NOT CPM_ARGS_GIT_TAG)
+  if (NOT DEFINED CPM_ARGS_GIT_TAG)
     set(CPM_ARGS_GIT_TAG v${CPM_ARGS_VERSION})
   endif()
 
+  set(FETCH_CONTENT_DECLARE_EXTRA_OPTS "")
+
+  if (CPM_SOURCE_ROOT AND NOT DEFINED CPM_ARGS_SOURCE_DIR)
+    string(TOLOWER ${CPM_ARGS_NAME} lname)
+    string(REPLACE "-" "_" source_path_name ${lname})
+    list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS SOURCE_DIR ${CPM_SOURCE_ROOT}/${source_path_name})
+  endif()
+
   list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_TAG ${CPM_ARGS_GIT_TAG})
 
   if(CPM_ARGS_DOWNLOAD_ONLY)
@@ -110,11 +126,11 @@ function(CPMAddPackage)
   endif()
 
   if (CPM_ARGS_GITLAB_REPOSITORY)
-    list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_REPOSITORY "https://gitlab.com/${CPM_ARGS_GITHUB_REPOSITORY}.git")
+    list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_REPOSITORY "https://gitlab.com/${CPM_ARGS_GITLAB_REPOSITORY}.git")
   endif()
 
   if (${CPM_ARGS_NAME} IN_LIST CPM_PACKAGES)
-    CPM_GET_PACKAGE_VERSION(${CPM_ARGS_NAME})
+    CPM_GET_PACKAGE_VERSION(${CPM_ARGS_NAME} CPM_PACKAGE_VERSION)
     if(${CPM_PACKAGE_VERSION} VERSION_LESS ${CPM_ARGS_VERSION})
       message(WARNING "${CPM_INDENT} requires a newer version of ${CPM_ARGS_NAME} (${CPM_ARGS_VERSION}) than currently included (${CPM_PACKAGE_VERSION}).")
     endif()
@@ -143,7 +159,7 @@ function(CPMAddPackage)
     endforeach()
   endif()
 
-  CPM_DECLARE_PACKAGE(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION} ${CPM_ARGS_GIT_TAG} "${CPM_ARGS_UNPARSED_ARGUMENTS}")
+  CPM_DECLARE_PACKAGE(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION} ${CPM_ARGS_GIT_TAG} "${CPM_ARGS_UNPARSED_ARGUMENTS}" ${FETCH_CONTENT_DECLARE_EXTRA_OPTS})
   CPM_FETCH_PACKAGE(${CPM_ARGS_NAME} ${DOWNLOAD_ONLY})
   CPMGetProperties(${CPM_ARGS_NAME})
   SET(${CPM_ARGS_NAME}_SOURCE_DIR "${${CPM_ARGS_NAME}_SOURCE_DIR}" PARENT_SCOPE)
@@ -154,6 +170,11 @@ endfunction()
 function (CPM_DECLARE_PACKAGE PACKAGE VERSION GIT_TAG)
   message(STATUS "${CPM_INDENT} adding package ${PACKAGE}@${VERSION} (${GIT_TAG})")
 
+  if (${CPM_DRY_RUN}) 
+    message(STATUS "${CPM_INDENT} package not declared (dry run)")
+    return()
+  endif()
+
   FetchContent_Declare(
     ${PACKAGE}
     ${ARGN}
@@ -161,6 +182,12 @@ function (CPM_DECLARE_PACKAGE PACKAGE VERSION GIT_TAG)
 endfunction()
 
 function (CPM_FETCH_PACKAGE PACKAGE DOWNLOAD_ONLY)  
+
+  if (${CPM_DRY_RUN}) 
+    message(STATUS "${CPM_INDENT} package ${PACKAGE} not fetched (dry run)")
+    return()
+  endif()
+
   set(CPM_OLD_INDENT "${CPM_INDENT}")
   set(CPM_INDENT "${CPM_INDENT} ${PACKAGE}:")
   if(${DOWNLOAD_ONLY})
@@ -174,6 +201,9 @@ function (CPM_FETCH_PACKAGE PACKAGE DOWNLOAD_ONLY)
 endfunction()
 
 function (CPMGetProperties PACKAGE)
+  if (${CPM_DRY_RUN}) 
+    return()
+  endif()
   FetchContent_GetProperties(${PACKAGE})
   string(TOLOWER ${PACKAGE} lpackage)
   SET(${PACKAGE}_SOURCE_DIR "${${lpackage}_SOURCE_DIR}" PARENT_SCOPE)
@@ -186,8 +216,8 @@ function(CPMRegisterPackage PACKAGE VERSION)
   set("CPM_PACKAGE_${PACKAGE}_VERSION" ${VERSION} CACHE INTERNAL "")
 endfunction()
 
-function(CPM_GET_PACKAGE_VERSION PACKAGE)
-  set(CPM_PACKAGE_VERSION "${CPM_PACKAGE_${PACKAGE}_VERSION}" PARENT_SCOPE)
+function(CPM_GET_PACKAGE_VERSION PACKAGE OUTPUT)
+  set(${OUTPUT} "${CPM_PACKAGE_${PACKAGE}_VERSION}" PARENT_SCOPE)
 endfunction()
 
 function(CPM_PARSE_OPTION OPTION)
@@ -199,6 +229,11 @@ function(CPM_PARSE_OPTION OPTION)
   set(OPTION_VALUE "${OPTION_VALUE}" PARENT_SCOPE)
 endfunction()
 
+function(CPM_GET_VERSION_FROM_GIT_TAG GIT_TAG RESULT)
+  string(REGEX MATCH "v?([0123456789.]*).*" _ ${GIT_TAG})
+  SET(${RESULT} ${CMAKE_MATCH_1} PARENT_SCOPE)
+endfunction()
+
 function (CPM_HANDLE_OLD_VERSION NEW_CPM_VERSION)
   
   message(AUTHOR_WARNING "${CPM_INDENT} \
@@ -207,4 +242,4 @@ It is recommended to upgrade CPM to the most recent version. \
 See https://github.com/TheLartians/CPM for more information."
   )
 
-endfunction()
+endfunction()

cmake/testing.cmake

@@ -0,0 +1,10 @@
+
+function(ASSERT_EQUAL)
+  if (NOT ARGC EQUAL 2) 
+    message(FATAL_ERROR "assertion failed: invalid argument count: ${ARGC}")
+  endif()
+
+  if (NOT ${ARGV0} EQUAL ${ARGV1})
+    message(FATAL_ERROR "assertion failed: '${ARGV0}' != '${ARGV1}'")
+  endif()
+endfunction()

examples/boost/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleBoost main.cpp)
+set_target_properties(CPMExampleBoost PROPERTIES CXX_STANDARD 17)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME boost
+  GITHUB_REPOSITORY Orphis/boost-cmake
+  VERSION 1.67.0
+)
+
+target_link_libraries(CPMExampleBoost PRIVATE Boost::system pthread)

examples/boost/main.cpp

@@ -0,0 +1,30 @@
+//
+// timer.cpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <iostream>
+#include <boost/asio.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+
+void print(const boost::system::error_code& /*e*/)
+{
+  std::cout << "Hello, world!" << std::endl;
+}
+
+int main()
+{
+  boost::asio::io_service io;
+
+  boost::asio::deadline_timer t(io, boost::posix_time::seconds(1));
+  t.async_wait(&print);
+
+  io.run();
+
+  return 0;
+}

examples/cxxopts/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME cxxopts
+  GITHUB_REPOSITORY jarro2783/cxxopts
+  VERSION 2.2.0
+  OPTIONS
+    "CXXOPTS_BUILD_EXAMPLES Off"
+    "CXXOPTS_BUILD_TESTS Off"
+)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleCXXOpts main.cpp)
+target_link_libraries(CPMExampleCXXOpts cxxopts)
+set_target_properties(CPMExampleCXXOpts PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")

examples/cxxopts/main.cpp

@@ -0,0 +1,23 @@
+#include <cxxopts.hpp>
+#include <iostream>
+
+int main(int argc, char ** argv) {
+  cxxopts::Options options("MyProgram", "One line description of MyProgram");
+  options.add_options()
+    ("h,help", "Show help")
+    ("d,debug", "Enable debugging")
+    ("f,file", "File name", cxxopts::value<std::string>());
+
+  auto result = options.parse(argc, argv);
+  
+  if (result["help"].as<bool>()) {
+    std::cout << options.help() << std::endl;
+    return 0;
+  }
+
+  for (auto arg: result.arguments()) {
+    std::cout << "option: " << arg.key() << ": " << arg.value() << std::endl;
+  }
+
+  return 0;
+}

examples/doctest/CMakeLists.txt

@@ -17,7 +17,6 @@ CPMAddPackage(
 CPMAddPackage(
   NAME doctest
   GITHUB_REPOSITORY onqtam/doctest
-  VERSION 2.3.2
   GIT_TAG 2.3.2
 )
 

examples/entt/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME EnTT
+  VERSION 3.1.1
+  GITHUB_REPOSITORY skypjack/entt
+  # EnTT's CMakeLists screws with configuration options
+  DOWNLOAD_ONLY True
+)
+
+if (EnTT_ADDED)
+  add_library(EnTT INTERFACE)
+  target_include_directories(EnTT INTERFACE ${EnTT_SOURCE_DIR}/src)
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMEnTTExample "main.cpp")
+set_target_properties(CPMEnTTExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMEnTTExample EnTT)

examples/entt/main.cpp

@@ -0,0 +1,54 @@
+#include <entt/entt.hpp>
+#include <cstdint>
+
+struct position {
+    float x;
+    float y;
+};
+
+struct velocity {
+    float dx;
+    float dy;
+};
+
+void update(entt::registry &registry) {
+    auto view = registry.view<position, velocity>();
+
+    for(auto entity: view) {
+        // gets only the components that are going to be used ...
+
+        auto &vel = view.get<velocity>(entity);
+
+        vel.dx = 0.;
+        vel.dy = 0.;
+
+        // ...
+    }
+}
+
+void update(std::uint64_t dt, entt::registry &registry) {
+    registry.view<position, velocity>().each([dt](auto &pos, auto &vel) {
+        // gets all the components of the view at once ...
+
+        pos.x += vel.dx * dt;
+        pos.y += vel.dy * dt;
+
+        // ...
+    });
+}
+
+int main() {
+    entt::registry registry;
+    std::uint64_t dt = 16;
+
+    for(auto i = 0; i < 10; ++i) {
+        auto entity = registry.create();
+        registry.assign<position>(entity, i * 1.f, i * 1.f);
+        if(i % 2 == 0) { registry.assign<velocity>(entity, i * .1f, i * .1f); }
+    }
+
+    update(dt, registry);
+    update(registry);
+
+    // ...
+}

examples/linenoise/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME linenoise
+  GIT_TAG 1.0
+  GITHUB_REPOSITORY antirez/linenoise
+)
+
+if(linenoise_ADDED)
+  add_library(linenoise ${linenoise_SOURCE_DIR}/linenoise.c)
+  target_include_directories(linenoise PUBLIC ${linenoise_SOURCE_DIR})
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMlinenoiseExample "main.cpp")
+set_target_properties(CPMlinenoiseExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMlinenoiseExample linenoise)

examples/linenoise/main.cpp

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "linenoise.h"
+
+
+void completion(const char *buf, linenoiseCompletions *lc) {
+    if (buf[0] == 'h') {
+        linenoiseAddCompletion(lc,"hello");
+        linenoiseAddCompletion(lc,"hello there");
+    }
+}
+
+int main(int argc, char **argv) {
+    char *line;
+    char *prgname = argv[0];
+
+    /* Parse options, with --multiline we enable multi line editing. */
+    while(argc > 1) {
+        argc--;
+        argv++;
+        if (!strcmp(*argv,"--multiline")) {
+            linenoiseSetMultiLine(1);
+            printf("Multi-line mode enabled.\n");
+        } else if (!strcmp(*argv,"--keycodes")) {
+            linenoisePrintKeyCodes();
+            exit(0);
+        } else {
+            fprintf(stderr, "Usage: %s [--multiline] [--keycodes]\n", prgname);
+            exit(1);
+        }
+    }
+
+    /* Set the completion callback. This will be called every time the
+     * user uses the <tab> key. */
+    linenoiseSetCompletionCallback(completion);
+
+    /* Load history from file. The history file is just a plain text file
+     * where entries are separated by newlines. */
+    linenoiseHistoryLoad("history.txt"); /* Load the history at startup */
+
+    /* Now this is the main loop of the typical linenoise-based application.
+     * The call to linenoise() will block as long as the user types something
+     * and presses enter.
+     *
+     * The typed string is returned as a malloc() allocated string by
+     * linenoise, so the user needs to free() it. */
+    while((line = linenoise("hello> ")) != NULL) {
+        /* Do something with the string. */
+        if (line[0] != '\0' && line[0] != '/') {
+            printf("echo: '%s'\n", line);
+            linenoiseHistoryAdd(line); /* Add to the history. */
+            linenoiseHistorySave("history.txt"); /* Save the history on disk. */
+        } else if (!strncmp(line,"/historylen",11)) {
+            /* The "/historylen" command will change the history len. */
+            int len = atoi(line+11);
+            linenoiseHistorySetMaxLen(len);
+        } else if (line[0] == '/') {
+            printf("Unreconized command: %s\n", line);
+        }
+        free(line);
+    }
+    return 0;
+}

examples/parser-lua/CMakeLists.txt

@@ -7,7 +7,7 @@ include(../../cmake/CPM.cmake)
 CPMAddPackage(
   NAME Glue
   GIT_REPOSITORY https://github.com/TheLartians/Glue.git
-  VERSION 0.8.1
+  VERSION 0.8.2
   OPTIONS 
     "GLUE_ENABLE_LUA ON"
     "GLUE_BUILD_LUA ON"

examples/range-v3/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME range-v3
+  URL https://github.com/ericniebler/range-v3/archive/0.5.0.zip
+  VERSION 0.5.0
+  # the range-v3 CMakeLists screws with configuration options
+  DOWNLOAD_ONLY True
+)
+
+if(range-v3_ADDED) 
+  add_library(range-v3 INTERFACE IMPORTED)
+  target_include_directories(range-v3 INTERFACE "${range-v3_SOURCE_DIR}/include")
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMRangev3Example "main.cpp")
+set_target_properties(CPMRangev3Example PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMRangev3Example range-v3)

examples/range-v3/main.cpp

@@ -0,0 +1,44 @@
+// Range v3 library
+//
+//  Copyright Jeff Garland 2017
+//
+//  Use, modification and distribution is subject to the
+//  Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//
+// Project home: https://github.com/ericniebler/range-v3
+//
+
+//[any_all_none_of]]
+// Demonstrates any_of, all_of, none_of
+// output
+// vector: [6,2,3,4,5,6]
+// vector any_of is_six: true
+// vector all_of is_six: false
+// vector none_of is_six: false
+
+#include <range/v3/algorithm/all_of.hpp>
+#include <range/v3/algorithm/any_of.hpp>
+#include <range/v3/algorithm/for_each.hpp>
+#include <range/v3/algorithm/none_of.hpp>
+#include <range/v3/view/all.hpp>
+
+#include <iostream>
+#include <vector>
+using std::cout;
+
+auto is_six = [](int i) { return i == 6; };
+
+int
+main()
+{
+    std::vector<int> v{6, 2, 3, 4, 5, 6};
+    cout << std::boolalpha;
+    cout << "vector: " << ranges::view::all(v) << '\n';
+
+    cout << "vector any_of is_six: " << ranges::any_of(v, is_six) << '\n';
+    cout << "vector all_of is_six: " << ranges::all_of(v, is_six) << '\n';
+    cout << "vector none_of is_six: " << ranges::none_of(v, is_six) << '\n';
+}
+//[any_all_none_of]]

examples/sol2/CMakeLists.txt

@@ -0,0 +1,45 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME lua
+  GIT_REPOSITORY https://github.com/lua/lua.git
+  VERSION 5.3.5
+  DOWNLOAD_ONLY YES
+)
+
+if (lua_ADDED)
+  # lua has no CMakeLists, so we create our own target
+
+  FILE(GLOB lua_sources ${lua_SOURCE_DIR}/*.c)
+  add_library(lua STATIC ${lua_sources})
+
+  target_include_directories(lua
+    PUBLIC
+      $<BUILD_INTERFACE:${lua_SOURCE_DIR}>
+  )
+endif()
+
+
+CPMAddPackage(
+  NAME sol2
+  URL https://github.com/ThePhD/sol2/archive/v3.0.2.zip
+  VERSION 3.0.2
+  DOWNLOAD_ONLY YES
+)
+
+if (sol2_ADDED)
+  add_library(sol2 INTERFACE IMPORTED)
+  target_include_directories(sol2 INTERFACE ${sol2_SOURCE_DIR}/include)
+  target_link_libraries(sol2 INTERFACE lua)
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMSol2Example "main.cpp")
+set_target_properties(CPMSol2Example PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMSol2Example sol2)
+

examples/sol2/main.cpp

@@ -0,0 +1,16 @@
+#include <sol/sol.hpp>
+#include <cassert>
+
+struct vars {
+    int boop = 0;
+};
+
+int main() {
+    sol::state lua;
+    lua.open_libraries( sol::lib::base );
+    lua.new_usertype<vars>("vars", "boop", &vars::boop);
+    lua.script("beep = vars.new()\n"
+               "beep.boop = 1\n"
+               "print('beep boop')");
+    assert(lua.get<vars>("beep").boop == 1);
+}

test/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+file(GLOB tests "${CMAKE_CURRENT_SOURCE_DIR}/unit/*.cmake")
+
+enable_testing()
+
+foreach(test ${tests})
+  message(STATUS "adding test: ${test}")
+  add_test(
+    NAME ${test} 
+    COMMAND ${CMAKE_COMMAND} -DCPM_PATH=${CMAKE_CURRENT_SOURCE_DIR}/../cmake -P "${test}"
+  )
+endforeach()

test/unit/dependency_properties.cmake

@@ -0,0 +1,30 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+include(${CPM_PATH}/CPM.cmake)
+include(${CPM_PATH}/testing.cmake)
+
+set(CPM_DRY_RUN ON)
+
+CPMAddPackage(
+  NAME A
+  GIT_TAG 1.2.3
+)
+
+CPM_GET_PACKAGE_VERSION(A VERSION)
+ASSERT_EQUAL(${VERSION} "1.2.3")
+
+CPMAddPackage(
+  NAME B
+  GIT_TAG v2.3.1
+)
+
+CPM_GET_PACKAGE_VERSION(B VERSION)
+ASSERT_EQUAL(${VERSION} "2.3.1")
+
+CPMAddPackage(
+  NAME C
+  GIT_TAG v3.1.2-a
+)
+
+CPM_GET_PACKAGE_VERSION(C VERSION)
+ASSERT_EQUAL(${VERSION} "3.1.2")

test/unit/version_from_git_tag.cmake

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+include(${CPM_PATH}/CPM.cmake)
+include(${CPM_PATH}/testing.cmake)
+
+CPM_GET_VERSION_FROM_GIT_TAG("1.2.3" VERSION)
+ASSERT_EQUAL("1.2.3" ${VERSION})
+
+CPM_GET_VERSION_FROM_GIT_TAG("v1.2.3" VERSION)
+ASSERT_EQUAL("1.2.3" ${VERSION})
+
+CPM_GET_VERSION_FROM_GIT_TAG("1.2.3-a" VERSION)
+ASSERT_EQUAL("1.2.3" ${VERSION})
+
+CPM_GET_VERSION_FROM_GIT_TAG("v1.2.3-a" VERSION)
+ASSERT_EQUAL("1.2.3" ${VERSION})