add github action to publish cpm on release

* add VERSION_PREFIX argument

* add fmt example

* add VERSION_PREFIX note to readme

* rollback, add info about determining version from git tag

* rollback version

.github/workflows/macos.yml

@@ -0,0 +1,16 @@
+name: MacOS
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: macOS-10.14
+    
+    steps:
+    - uses: actions/checkout@v1
+    
+    - name: run tests
+      run: |
+        cmake -Htest -Bbuild/test
+        cmake --build build/test --target test-verbose

.github/workflows/publish.yaml

@@ -0,0 +1,20 @@
+name: Publish
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  build:
+    name: Publish CPM.cmake
+    runs-on: ubuntu-latest
+    steps:
+      - name: Upload CPM.cmake to release
+        uses: svenstaro/upload-release-action@v1-release
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          file: cmake/CPM.cmake
+          asset_name: CPM.cmake
+          tag: ${{ github.ref }}
+          overwrite: true

.github/workflows/ubuntu.yml

@@ -0,0 +1,23 @@
+name: Ubuntu
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-18.04
+    
+    steps:
+    - uses: actions/checkout@v1
+    
+    - name: install updates
+      run: |
+        wget -O cmake.sh https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh 
+        sudo sh cmake.sh --skip-license --exclude-subdir --prefix=/usr/local
+        export PATH=/usr/local/bin:$PATH
+        cmake --version
+    
+    - name: run tests
+      run: |
+        cmake -Htest -Bbuild/test
+        cmake --build build/test --target test-verbose

.github/workflows/windows.yml

@@ -0,0 +1,16 @@
+name: Windows
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: windows-2019
+    
+    steps:
+    - uses: actions/checkout@v1
+    
+    - name: run tests
+      run: |
+        cmake -Htest -Bbuild/test
+        cmake --build build/test --target test-verbose

.gitignore

@@ -1,10 +1,3 @@
-CMakeCache.txt
-CMakeFiles
-CMakeScripts
-Testing
-Makefile
-cmake_install.cmake
-install_manifest.txt
-compile_commands.json
-CTestTestfile.cmake
-build
+/build*
+/.vscode
+*.DS_Store

.travis.yml

@@ -1,11 +1,13 @@
-
 language: cpp
 sudo: require
+dist: xenial
 
 common_sources: &all_sources
   - ubuntu-toolchain-r-test
   - llvm-toolchain-trusty
-  - llvm-toolchain-trusty-6.0
+
+python:
+  - 3.7
 
 matrix:
   include:
@@ -14,7 +16,7 @@ matrix:
       addons: &gcc8
         apt:
           sources: *all_sources
-          packages: 
+          packages:
             - g++-8
       env:
         - MATRIX_EVAL="export CC=gcc-8; export CXX=g++-8;"
@@ -22,11 +24,11 @@ matrix:
     - os: linux
       compiler: clang
       addons:
-          apt:
-              sources: *all_sources
-              packages:
-                - g++-8
-                - clang-6.0
+        apt:
+          sources: *all_sources
+          packages:
+            - g++-8
+            - clang-6.0
       env:
         - MATRIX_EVAL="export CC=clang-6.0; export CXX=clang++-6.0;"
 
@@ -34,12 +36,15 @@ before_install:
   # Update compilers
   - eval "${MATRIX_EVAL}"
   - echo "CC=$CC CXX=$CXX"
+  # Install a supported cmake version (>= 3.14)
+  - wget -O cmake.sh https://cmake.org/files/v3.14/cmake-3.14.0-Linux-x86_64.sh
+  - sudo sh cmake.sh --skip-license --exclude-subdir --prefix=/usr/local
+  - export PATH=/usr/local/bin:$PATH
+  - cmake --version
 
 script:
-  - cmake -Htests/simple -Bbuild/simple 
-  - cmake --build build/simple
-  - CTEST_OUTPUT_ON_FAILURE=1 cmake --build build/simple --target test
-  - cmake -Htests/complex -Bbuild/complex
-  - cmake --build build/complex
-  - CTEST_OUTPUT_ON_FAILURE=1 cmake --build build/complex --target test
- 
+  # unit tests
+  - cmake -Htest -Bbuild/test
+  - cmake --build build/test --target test-verbose
+  # build examples
+  - python3 examples/build_all.py

README.md

@@ -1,43 +1,273 @@
-[![Build Status](https://travis-ci.com/TheLartians/CPM.svg?branch=master)](https://travis-ci.com/TheLartians/CPM)
+[![Build Status](https://travis-ci.com/TheLartians/CPM.cmake.svg?branch=master)](https://travis-ci.com/TheLartians/CPM.cmake)
+[![Actions Status](https://github.com/TheLartians/CPM.cmake/workflows/MacOS/badge.svg)](https://github.com/TheLartians/CPM.cmake/actions)
+[![Actions Status](https://github.com/TheLartians/CPM.cmake/workflows/Windows/badge.svg)](https://github.com/TheLartians/CPM.cmake/actions)
+[![Actions Status](https://github.com/TheLartians/CPM.cmake/workflows/Ubuntu/badge.svg)](https://github.com/TheLartians/CPM.cmake/actions)
 
-# CPM
+<p align="center">
+  <img src="./logo/CPM.png" height="100" />
+</p>
 
-CPM is a very simple package manager written in Cmake based on the amazing [DownloadProject](https://github.com/Crascit/DownloadProject) script. It is extremely easy to use and drastically simplifies the inclusion of other Cmake-based projects from github.
+# Setup-free CMake dependency management
 
-# Usage
+CPM.cmake is a CMake script that adds dependency management capabilities to CMake.
+It's built as a thin wrapper around CMake's [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html) module that adds version control, caching and a simple API.
 
-To add a new dependency to your project simply add the Projects target name, the git URL and the version. If the git tag for this version does not match the pattern `v$VERSION`, then the exact branch or tag can be specified with the `GIT_TAG` argument.
+## Manage everything
+
+Any downloadable project or resource can be added as a version-controlled dependency though CPM, it is not necessary to modify or package anything.
+Projects using modern CMake are automatically configured and their targets can be used immediately.
+For everything else, the targets can be created manually after the dependency has been downloaded (see the [snippets](#snippets) below for examples).
+
+## Usage
+
+After `CPM.cmake` has been [added](#adding-cpm) to your project, the function `CPMAddPackage` or `CPMFindPackage` can be used to fetch and configure a dependency.
+Afterwards, any targets defined in the dependency can be used directly.
+`CPMFindPackage` and `CPMAddPackage` take the following named parameters.
 
 ```cmake
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
-project(MyParser)
-
-# add dependencies
-include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/CPM.cmake)
-
 CPMAddPackage(
-  NAME LarsParser
-  VERSION 1.2
-  GIT_REPOSITORY https://github.com/TheLartians/Parser.git
-  GIT_TAG master # optional
+  NAME          # The unique name of the dependency (should be the exported 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)
+  [...]         # Origin parameters forwarded to FetchContent_Declare, see below
 )
+```
+
+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.
+On the other hand, if `VERSION` hasn't been explicitly specified, CPM can automatically identify the version from the git tag in some common cases. 
+`GIT_TAG` can also be set to a specific commit or a branch name such as `master` to always download the most recent version.
+The optional argument `FIND_PACKAGE_ARGUMENTS` can be specified to a string of parameters that will be passed to `find_package` if enabled (see below).
+
+After calling `CPMAddPackage` or `CPMFindPackage`, the following variables are defined in the local scope, where `<dependency>` is the name of the dependency.
+
+- `<dependency>_SOURCE_DIR` is the path to the source of the dependency.
+- `<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`.
+
+The difference between `CPMFindPackage` and `CPMAddPackage` is that `CPMFindPackage` will try to find a local dependency via CMake's `find_package` and fallback to `CPMAddPackage` if the dependency is not found.
+This behaviour can be also modified globally via [CPM options](#options).
+
+## Full CMakeLists Example
+
+```cmake
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+# create project
+project(MyProject)
 
 # add executable
-set (CMAKE_CXX_STANDARD 17)
-add_executable(my-parser my-parser.cpp)
-target_link_libraries(cpm-test LarsParser)
+add_executable(tests tests.cpp)
+
+# add dependencies
+include(cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME Catch2
+  GITHUB_REPOSITORY catchorg/Catch2
+  VERSION 2.5.0
+)
+
+# link dependencies
+target_link_libraries(tests Catch2)
 ```
 
-# Installation
+See the [examples directory](https://github.com/TheLartians/CPM/tree/master/examples) for complete examples with source code or the [wiki](https://github.com/TheLartians/CPM/wiki/More-Snippets) for example snippets.
 
-To add CPM to your current project, copy the scripts in the `cmake` directory into you current project project. The command below will perform this automatically.
+## Adding CPM
+
+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
-wget -qO- https://github.com/TheLartians/CPM/releases/download/v0.1/cmake.zip | bsdtar -xvf-
+mkdir -p cmake
+wget -O cmake/CPM.cmake https://raw.githubusercontent.com/TheLartians/CPM.cmake/master/cmake/CPM.cmake
 ```
 
-# Limitations
+You can also use CMake to download CPM for you. See the [wiki](https://github.com/TheLartians/CPM/wiki/Adding-CPM) for more details.
 
-- First version used: in diamond dependency graphs (e.g. `A` depends on `C`(v1.1) and `A` depends on `B` depends on `C`(v1.2)) the first added dependency will be used (in this case `C`@1.1).
-- No possibility not automatically update dependencies. To update a dependency, version numbers or git tags in the cmake scripts must be adapted manually.
+## Updating CPM
+
+To update CPM to the newest version, update the script in the project's root directory, for example by running the command above.
+Dependencies using CPM will automatically use the updated script of the outermost project.
+
+## Advantages
+
+- **Small and reusable projects** CPM takes care of all project dependencies, allowing developers to focus on creating small, well-tested libraries.
+- **Cross-Platform** CPM adds projects directly at the configure stage and is compatible with all CMake toolchains and generators.
+- **Reproducable builds** By versioning dependencies via git commits or tags it is ensured that a project will always be buildable.
+- **Recursive dependencies** Ensures that no dependency is added twice and all are 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** Simply add all external sources as a dependency.
+- **Simple source distribution** CPM makes including projects with source files and dependencies easy, reducing the need for monolithic header files or git submodules.
+
+## Limitations
+
+- **No pre-built binaries** For every new build directory, all dependencies are initially downloaded and built from scratch. To avoid extra downloads it is recommend to set the [`CPM_SOURCE_CACHE`](#CPM_SOURCE_CACHE) environmental variable. Using a caching compiler such as [ccahe](https://github.com/TheLartians/Ccache.cmake) can drastically reduce build time.
+- **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 examples). For best practices on preparing 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 a warning. This can be resolved by adding a new version of the dependency in the outermost project.
+
+For projects with more complex needs and where an extra setup step doesn't matter, it may be worth to check out an external C++ package manager such as [vcpkg](https://github.com/microsoft/vcpkg), [conan](https://conan.io) or [hunter](https://github.com/ruslo/hunter).
+Dependencies added with `CPMFindPackage` should work with external package managers.
+Additionally, the option [`CPM_USE_LOCAL_PACKAGES`](#cpmuselocalpackages) will enable `find_package` for all CPM dependencies.
+
+## Options
+
+### CPM_SOURCE_CACHE
+
+To avoid re-downloading dependencies, CPM has an option `CPM_SOURCE_CACHE` that can be passed to CMake as `-DCPM_SOURCE_CACHE=<path to an external download directory>`.
+This will also allow projects to be configured offline, as long as the dependencies have been added to the cache before.
+It may also be defined system-wide as an environmental variable, e.g. by exporting `CPM_SOURCE_CACHE` in your `.bashrc` or `.bash_profile`.
+
+```bash
+export CPM_SOURCE_CACHE=$HOME/.cache/CPM
+```
+
+Note that passing the variable as a configure option to CMake will always override the value set by the environmental variable.
+
+### CPM_DOWNLOAD_ALL
+
+If set, CPM will forward all calls to `CPMFindPackage` as `CPMAddPackage`.
+This is useful to create reproducible builds or to determine if the source parameters have all been set correctly.
+This can also be set as an environmental variable.
+
+### 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.
+These options can also be set as environmental variables.
+
+## 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)
+
+```cmake
+CPMAddPackage(
+  NAME Catch2
+  GITHUB_REPOSITORY catchorg/Catch2
+  VERSION 2.5.0
+)
+```
+
+### [Boost (via boost-cmake)](https://github.com/Orphis/boost-cmake)
+
+```CMake
+CPMAddPackage(
+  NAME boost-cmake
+  GITHUB_REPOSITORY Orphis/boost-cmake
+  VERSION 1.67.0
+)
+```
+
+### [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 deprecated 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(
+  NAME benchmark
+  GITHUB_REPOSITORY google/benchmark
+  VERSION 1.4.1
+  OPTIONS
+    "BENCHMARK_ENABLE_TESTING Off"
+)
+
+if (benchmark_ADDED)
+  # compile with C++17
+  set_target_properties(benchmark PROPERTIES CXX_STANDARD 17)
+endif()
+```
+
+### [nlohmann/json](https://github.com/nlohmann/json)
+
+```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 IMPORTED)
+  target_include_directories(nlohmann_json INTERFACE ${nlohmann_json_SOURCE_DIR})
+endif()
+```
+
+### [Range-v3](https://github.com/ericniebler/range-v3)
+
+```Cmake
+CPMAddPackage(
+  NAME range-v3
+  URL https://github.com/ericniebler/range-v3/archive/0.5.0.zip
+  VERSION 0.5.0
+  # the range-v3 CMakeLists screws with configuration options
+  DOWNLOAD_ONLY True
+)
+
+if(range-v3_ADDED) 
+  add_library(range-v3 INTERFACE IMPORTED)
+  target_include_directories(range-v3 INTERFACE "${range-v3_SOURCE_DIR}/include")
+endif()
+```
+
+### [Lua](https://www.lua.org)
+
+```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 CMake support, 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()
+```
+
+For a full example on using CPM to download and configure lua with sol2 see [here](examples/sol2).
+
+### Full Examples
+
+See the [examples directory](https://github.com/TheLartians/CPM/tree/master/examples) for full examples with source code and check out the [wiki](https://github.com/TheLartians/CPM/wiki/More-Snippets) for many more example snippets.

cmake/CPM.cmake

@@ -1,63 +1,329 @@
-set(_CPM_Dir "${CMAKE_CURRENT_LIST_DIR}")
+# TheLartians/CPM - A simple Git dependency manager
+# =================================================
+# See https://github.com/TheLartians/CPM for usage and update instructions.
+#
+# MIT License
+# ----------- 
+#[[
+  Copyright (c) 2019 Lars Melchior
 
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+]]
+
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+set(CURRENT_CPM_VERSION 0.17)
+
+if(CPM_DIRECTORY)
+  if(NOT ${CPM_DIRECTORY} MATCHES ${CMAKE_CURRENT_LIST_DIR})
+    if (${CPM_VERSION} VERSION_LESS ${CURRENT_CPM_VERSION})
+      message(AUTHOR_WARNING "${CPM_INDENT} \
+A dependency is using a more recent CPM version (${CURRENT_CPM_VERSION}) than the current project (${CPM_VERSION}). \
+It is recommended to upgrade CPM to the most recent version. \
+See https://github.com/TheLartians/CPM.cmake for more information."
+      )
+    endif()
+    return()
+  endif()
+endif()
+
+option(CPM_USE_LOCAL_PACKAGES "Always try to use `find_package` to get dependencies" $ENV{CPM_USE_LOCAL_PACKAGES})
+option(CPM_LOCAL_PACKAGES_ONLY "Only use `find_package` to get dependencies" $ENV{CPM_LOCAL_PACKAGES_ONLY})
+option(CPM_DOWNLOAD_ALL "Always download dependencies from source" $ENV{CPM_DOWNLOAD_ALL})
+
+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)")
+
+if(DEFINED ENV{CPM_SOURCE_CACHE})
+  set(CPM_SOURCE_CACHE_DEFAULT $ENV{CPM_SOURCE_CACHE})
+else()
+  set(CPM_SOURCE_CACHE_DEFAULT OFF)
+endif()
+
+set(CPM_SOURCE_CACHE ${CPM_SOURCE_CACHE_DEFAULT} CACHE PATH "Directory to downlaod CPM dependencies")
+
+include(FetchContent)
 include(CMakeParseArguments)
-include(${_CPM_Dir}/DownloadProject.cmake)
 
-function(CPMHasPackage) 
-  
+# Initialize logging prefix
+if(NOT CPM_INDENT)
+  set(CPM_INDENT "CPM:")
+endif()
+
+function(cpm_find_package NAME VERSION)
+  string(REPLACE " " ";" EXTRA_ARGS "${ARGN}")
+  find_package(${NAME} ${VERSION} ${EXTRA_ARGS})
+  if(${CPM_ARGS_NAME}_FOUND)
+    message(STATUS "${CPM_INDENT} using local package ${CPM_ARGS_NAME}@${${CPM_ARGS_NAME}_VERSION}")
+    CPMRegisterPackage(${CPM_ARGS_NAME} "${${CPM_ARGS_NAME}_VERSION}")
+    set(CPM_PACKAGE_FOUND YES PARENT_SCOPE)
+  else()
+    set(CPM_PACKAGE_FOUND NO PARENT_SCOPE)
+  endif()
 endfunction()
 
-function(CPMAddPackage)
-  set(options QUIET)
-    
+# Find a package locally or fallback to CPMAddPackage
+function(CPMFindPackage)
   set(oneValueArgs
     NAME
-    GIT_REPOSITORY
     VERSION
-    GIT_TAG
-    BINARY_DIR
+    FIND_PACKAGE_ARGUMENTS
   )
 
-  set(multiValueArgs "")
-
-  cmake_parse_arguments(CPM_ARGS "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-
-  if (NOT CPM_PACKAGES)
-    set(CPM_PACKAGES "")
+  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "" ${ARGN})
+  
+  if (CPM_DOWNLOAD_ALL)
+    CPMAddPackage(${ARGN})
+    cpm_export_variables()
+    return()
   endif()
 
-  if (NOT CPM_ARGS_BINARY_DIR)
-    set(CPM_ARGS_BINARY_DIR ${CMAKE_BINARY_DIR}/CPM-projects/${CPM_ARGS_NAME})
+  cpm_find_package(${CPM_ARGS_NAME} "${CPM_ARGS_VERSION}" ${CPM_ARGS_FIND_PACKAGE_ARGUMENTS})
+
+  if(NOT CPM_PACKAGE_FOUND)
+    CPMAddPackage(${ARGN})
+    cpm_export_variables()
   endif()
 
-  if (NOT CPM_PROJECT_DIR)
-    set(CPM_PROJECT_DIR "${CPM_ARGS_BINARY_DIR}")
+endfunction()
+
+# Download and add a package from source
+function(CPMAddPackage)
+
+  set(oneValueArgs
+    NAME
+    VERSION
+    GIT_TAG
+    DOWNLOAD_ONLY
+    GITHUB_REPOSITORY
+    GITLAB_REPOSITORY
+    SOURCE_DIR
+    DOWNLOAD_COMMAND
+    FIND_PACKAGE_ARGUMENTS
+  )
+
+  set(multiValueArgs
+    OPTIONS
+  )
+
+  cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" "${ARGN}")
+
+  if(CPM_USE_LOCAL_PACKAGES OR CPM_LOCAL_PACKAGES_ONLY)
+    cpm_find_package(${CPM_ARGS_NAME} "${CPM_ARGS_VERSION}" ${CPM_ARGS_FIND_PACKAGE_ARGUMENTS})
+
+    if(CPM_PACKAGE_FOUND)
+      return()
+    endif()
+
+    if(CPM_LOCAL_PACKAGES_ONLY) 
+      message(SEND_ERROR "CPM: ${CPM_ARGS_NAME} not found via find_package(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION})")
+    endif()
   endif()
 
-  if (NOT CPM_ARGS_GIT_TAG)
+  if (NOT DEFINED CPM_ARGS_VERSION)
+    if (DEFINED CPM_ARGS_GIT_TAG) 
+      cpm_get_version_from_git_tag("${CPM_ARGS_GIT_TAG}" CPM_ARGS_VERSION)
+    endif()
+    if (NOT DEFINED CPM_ARGS_VERSION) 
+      set(CPM_ARGS_VERSION 0)
+    endif()
+  endif()
+
+  if (NOT DEFINED CPM_ARGS_GIT_TAG)
     set(CPM_ARGS_GIT_TAG v${CPM_ARGS_VERSION})
   endif()
 
-  SET(CPM_TARGET_CMAKE_FILE "${CPM_PROJECT_DIR}")
+  list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_TAG ${CPM_ARGS_GIT_TAG})
+
+  if(CPM_ARGS_DOWNLOAD_ONLY)
+    set(DOWNLOAD_ONLY ${CPM_ARGS_DOWNLOAD_ONLY})
+  else()
+    set(DOWNLOAD_ONLY NO)
+  endif()
+
+  if (CPM_ARGS_GITHUB_REPOSITORY)
+    list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS GIT_REPOSITORY "https://github.com/${CPM_ARGS_GITHUB_REPOSITORY}.git")
+  endif()
+
+  if (CPM_ARGS_GITLAB_REPOSITORY)
+    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)
-    message(STATUS "CPM: package ${CPM_ARGS_NAME} already added")
+    CPMGetPackageVersion(${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()
+    if (CPM_ARGS_OPTIONS)
+      foreach(OPTION ${CPM_ARGS_OPTIONS})
+        cpm_parse_option(${OPTION})
+        if(NOT "${${OPTION_KEY}}" STREQUAL ${OPTION_VALUE})
+          message(WARNING "${CPM_INDENT} ignoring package option for ${CPM_ARGS_NAME}: ${OPTION_KEY} = ${OPTION_VALUE} (${${OPTION_KEY}})")
+        endif()
+      endforeach()
+    endif()
+    cpm_fetch_package(${CPM_ARGS_NAME} ${DOWNLOAD_ONLY})
+    cpm_get_fetch_properties(${CPM_ARGS_NAME})
+    SET(${CPM_ARGS_NAME}_SOURCE_DIR "${${CPM_ARGS_NAME}_SOURCE_DIR}")
+    SET(${CPM_ARGS_NAME}_BINARY_DIR "${${CPM_ARGS_NAME}_BINARY_DIR}")  
+    SET(${CPM_ARGS_NAME}_ADDED NO)
+    cpm_export_variables()
+    return()
+  endif()
+
+  CPMRegisterPackage(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION})
+
+  if (CPM_ARGS_OPTIONS)
+    foreach(OPTION ${CPM_ARGS_OPTIONS})
+      cpm_parse_option(${OPTION})
+      set(${OPTION_KEY} ${OPTION_VALUE} CACHE INTERNAL "")
+    endforeach()
+  endif()
+
+  set(FETCH_CONTENT_DECLARE_EXTRA_OPTS "")
+
+  if (DEFINED CPM_ARGS_GIT_TAG)
+    set(PACKAGE_INFO "${CPM_ARGS_GIT_TAG}")
   else()
-    message(STATUS "CPM: adding package ${CPM_ARGS_NAME}@${CPM_ARGS_VERSION}")
-    # update package data
-    LIST(APPEND CPM_PACKAGES ${CPM_ARGS_NAME})
-    # save package data
-    set(CPM_PACKAGES "${CPM_PACKAGES}" CACHE INTERNAL "CPM Packages")
-
-    configure_file(
-      "${_CPM_Dir}/CPMProject.CMakeLists.cmake.in"
-      "${CPM_TARGET_CMAKE_FILE}/CMakeLists.txt"
-      @ONLY
-    )
+    set(PACKAGE_INFO "${CPM_ARGS_VERSION}")
   endif()
 
-  if (NOT TARGET ${CPM_ARGS_NAME})
-    add_subdirectory(${CPM_TARGET_CMAKE_FILE} ${CPM_ARGS_BINARY_DIR})
+  if (DEFINED CPM_ARGS_DOWNLOAD_COMMAND)
+    set(FETCH_CONTENT_DECLARE_EXTRA_OPTS DOWNLOAD_COMMAND ${CPM_ARGS_DOWNLOAD_COMMAND})
+  elseif(DEFINED CPM_ARGS_SOURCE_DIR)
+    set(FETCH_CONTENT_DECLARE_EXTRA_OPTS SOURCE_DIR ${CPM_ARGS_SOURCE_DIR})
+  elseif (CPM_SOURCE_CACHE)
+    string(TOLOWER ${CPM_ARGS_NAME} lower_case_name)
+    set(origin_parameters ${CPM_ARGS_UNPARSED_ARGUMENTS})
+    list(SORT origin_parameters)
+    string(SHA1 origin_hash "${origin_parameters}")
+    set(download_directory ${CPM_SOURCE_CACHE}/${lower_case_name}/${origin_hash})
+    list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS SOURCE_DIR ${download_directory})
+    if (EXISTS ${download_directory})
+      list(APPEND FETCH_CONTENT_DECLARE_EXTRA_OPTS DOWNLOAD_COMMAND ":")
+      set(PACKAGE_INFO "${download_directory}")
+    else()
+      # remove timestamps so CMake will re-download the dependency
+      file(REMOVE_RECURSE ${CMAKE_BINARY_DIR}/_deps/${lower_case_name}-subbuild)
+      set(PACKAGE_INFO "${PACKAGE_INFO} -> ${download_directory}")
+    endif()
   endif()
 
+  cpm_declare_fetch(${CPM_ARGS_NAME} ${CPM_ARGS_VERSION} ${PACKAGE_INFO} "${CPM_ARGS_UNPARSED_ARGUMENTS}" ${FETCH_CONTENT_DECLARE_EXTRA_OPTS})
+  cpm_fetch_package(${CPM_ARGS_NAME} ${DOWNLOAD_ONLY})
+  cpm_get_fetch_properties(${CPM_ARGS_NAME})
+  SET(${CPM_ARGS_NAME}_ADDED YES)
+  cpm_export_variables()
+endfunction()
+
+# export variables available to the caller to the parent scope
+# expects ${CPM_ARGS_NAME} to be set
+macro(cpm_export_variables)
+  SET(${CPM_ARGS_NAME}_SOURCE_DIR "${${CPM_ARGS_NAME}_SOURCE_DIR}" PARENT_SCOPE)
+  SET(${CPM_ARGS_NAME}_BINARY_DIR "${${CPM_ARGS_NAME}_BINARY_DIR}" PARENT_SCOPE)
+  SET(${CPM_ARGS_NAME}_ADDED "${${CPM_ARGS_NAME}_ADDED}" PARENT_SCOPE)
+endmacro()
+
+# declares that a package has been added to CPM
+function(CPMRegisterPackage PACKAGE VERSION)
+  list(APPEND CPM_PACKAGES ${PACKAGE})
+  set(CPM_PACKAGES ${CPM_PACKAGES} CACHE INTERNAL "")
+  set("CPM_PACKAGE_${PACKAGE}_VERSION" ${VERSION} CACHE INTERNAL "")
+endfunction()
+
+# retrieve the current version of the package to ${OUTPUT}
+function(CPMGetPackageVersion PACKAGE OUTPUT)
+  set(${OUTPUT} "${CPM_PACKAGE_${PACKAGE}_VERSION}" PARENT_SCOPE)
+endfunction()
+
+# declares a package in FetchContent_Declare 
+function (cpm_declare_fetch PACKAGE VERSION INFO)
+  message(STATUS "${CPM_INDENT} adding package ${PACKAGE}@${VERSION} (${INFO})")
+
+  if (${CPM_DRY_RUN}) 
+    message(STATUS "${CPM_INDENT} package not declared (dry run)")
+    return()
+  endif()
+
+  FetchContent_Declare(
+    ${PACKAGE}
+    ${ARGN}
+  )
+endfunction()
+
+# returns properties for a package previously defined by cpm_declare_fetch
+function (cpm_get_fetch_properties PACKAGE)
+  if (${CPM_DRY_RUN}) 
+    return()
+  endif()
+  FetchContent_GetProperties(${PACKAGE})
+  string(TOLOWER ${PACKAGE} lpackage)
+  SET(${PACKAGE}_SOURCE_DIR "${${lpackage}_SOURCE_DIR}" PARENT_SCOPE)
+  SET(${PACKAGE}_BINARY_DIR "${${lpackage}_BINARY_DIR}" PARENT_SCOPE)
+endfunction()
+
+# downloads a previously declared package via FetchContent
+function (cpm_fetch_package PACKAGE DOWNLOAD_ONLY)  
+
+  if (${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})
+    if(NOT "${PACKAGE}_POPULATED")
+      FetchContent_Populate(${PACKAGE})
+    endif()
+  else()
+    FetchContent_MakeAvailable(${PACKAGE})
+  endif()
+  set(CPM_INDENT "${CPM_OLD_INDENT}")
+endfunction()
+
+# splits a package option
+function(cpm_parse_option OPTION)
+  string(REGEX MATCH "^[^ ]+" OPTION_KEY ${OPTION})
+  string(LENGTH ${OPTION} OPTION_LENGTH)
+  string(LENGTH ${OPTION_KEY} OPTION_KEY_LENGTH)
+  if (OPTION_KEY_LENGTH STREQUAL OPTION_LENGTH)
+    # no value for key provided, assume user wants to set option to "ON"
+    set(OPTION_VALUE "ON")
+  else()
+    math(EXPR OPTION_KEY_LENGTH "${OPTION_KEY_LENGTH}+1")
+    string(SUBSTRING ${OPTION} "${OPTION_KEY_LENGTH}" "-1" OPTION_VALUE)
+  endif()
+  set(OPTION_KEY "${OPTION_KEY}" PARENT_SCOPE)
+  set(OPTION_VALUE "${OPTION_VALUE}" PARENT_SCOPE)
+endfunction()
+
+# guesses the package version from a git tag
+function(cpm_get_version_from_git_tag GIT_TAG RESULT)
+  string(LENGTH ${GIT_TAG} length)
+  if (length EQUAL 40) 
+    # GIT_TAG is probably a git hash
+    SET(${RESULT} 0 PARENT_SCOPE)
+  else()
+    string(REGEX MATCH "v?([0123456789.]*).*" _ ${GIT_TAG})
+    SET(${RESULT} ${CMAKE_MATCH_1} PARENT_SCOPE)
+  endif()
 endfunction()

cmake/CPMProject.CMakeLists.cmake.in

@@ -1,27 +0,0 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
-if(TARGET @CPM_ARGS_NAME@)
-  return()
-endif()
-
-find_package(@CPM_ARGS_NAME@ @CPM_ARGS_VERSION@ QUIET)
-
-if(${PACKAGE_FOUND})
-  set_target_properties(@CPM_ARGS_NAME@ 
-    PROPERTIES
-      IMPORTED_GLOBAL True
-  )
-else()
-
-  download_project(
-    PROJ @CPM_ARGS_NAME@
-    GIT_REPOSITORY @CPM_ARGS_GIT_REPOSITORY@
-    GIT_TAG @CPM_ARGS_GIT_TAG@
-    UPDATE_DISCONNECTED 1
-    GIT_SHALLOW 1
-    PREFIX @CPM_ARGS_BINARY_DIR@/dl
-    QUIET
-  )
-
-  add_subdirectory(${@CPM_ARGS_NAME@_SOURCE_DIR} ${@CPM_ARGS_NAME@_BINARY_DIR})
-endif()

cmake/DownloadProject.CMakeLists.cmake.in

@@ -1,17 +0,0 @@
-# Distributed under the OSI-approved MIT License.  See accompanying
-# file LICENSE or https://github.com/Crascit/DownloadProject for details.
-
-cmake_minimum_required(VERSION 2.8.2)
-
-project(${DL_ARGS_PROJ}-download NONE)
-
-include(ExternalProject)
-ExternalProject_Add(${DL_ARGS_PROJ}-download
-                    ${DL_ARGS_UNPARSED_ARGUMENTS}
-                    SOURCE_DIR          "${DL_ARGS_SOURCE_DIR}"
-                    BINARY_DIR          "${DL_ARGS_BINARY_DIR}"
-                    CONFIGURE_COMMAND   ""
-                    BUILD_COMMAND       ""
-                    INSTALL_COMMAND     ""
-                    TEST_COMMAND        ""
-)

cmake/DownloadProject.cmake

@@ -1,182 +0,0 @@
-# Distributed under the OSI-approved MIT License.  See accompanying
-# file LICENSE or https://github.com/Crascit/DownloadProject for details.
-#
-# MODULE:   DownloadProject
-#
-# PROVIDES:
-#   download_project( PROJ projectName
-#                    [PREFIX prefixDir]
-#                    [DOWNLOAD_DIR downloadDir]
-#                    [SOURCE_DIR srcDir]
-#                    [BINARY_DIR binDir]
-#                    [QUIET]
-#                    ...
-#   )
-#
-#       Provides the ability to download and unpack a tarball, zip file, git repository,
-#       etc. at configure time (i.e. when the cmake command is run). How the downloaded
-#       and unpacked contents are used is up to the caller, but the motivating case is
-#       to download source code which can then be included directly in the build with
-#       add_subdirectory() after the call to download_project(). Source and build
-#       directories are set up with this in mind.
-#
-#       The PROJ argument is required. The projectName value will be used to construct
-#       the following variables upon exit (obviously replace projectName with its actual
-#       value):
-#
-#           projectName_SOURCE_DIR
-#           projectName_BINARY_DIR
-#
-#       The SOURCE_DIR and BINARY_DIR arguments are optional and would not typically
-#       need to be provided. They can be specified if you want the downloaded source
-#       and build directories to be located in a specific place. The contents of
-#       projectName_SOURCE_DIR and projectName_BINARY_DIR will be populated with the
-#       locations used whether you provide SOURCE_DIR/BINARY_DIR or not.
-#
-#       The DOWNLOAD_DIR argument does not normally need to be set. It controls the
-#       location of the temporary CMake build used to perform the download.
-#
-#       The PREFIX argument can be provided to change the base location of the default
-#       values of DOWNLOAD_DIR, SOURCE_DIR and BINARY_DIR. If all of those three arguments
-#       are provided, then PREFIX will have no effect. The default value for PREFIX is
-#       CMAKE_BINARY_DIR.
-#
-#       The QUIET option can be given if you do not want to show the output associated
-#       with downloading the specified project.
-#
-#       In addition to the above, any other options are passed through unmodified to
-#       ExternalProject_Add() to perform the actual download, patch and update steps.
-#       The following ExternalProject_Add() options are explicitly prohibited (they
-#       are reserved for use by the download_project() command):
-#
-#           CONFIGURE_COMMAND
-#           BUILD_COMMAND
-#           INSTALL_COMMAND
-#           TEST_COMMAND
-#
-#       Only those ExternalProject_Add() arguments which relate to downloading, patching
-#       and updating of the project sources are intended to be used. Also note that at
-#       least one set of download-related arguments are required.
-#
-#       If using CMake 3.2 or later, the UPDATE_DISCONNECTED option can be used to
-#       prevent a check at the remote end for changes every time CMake is run
-#       after the first successful download. See the documentation of the ExternalProject
-#       module for more information. It is likely you will want to use this option if it
-#       is available to you. Note, however, that the ExternalProject implementation contains
-#       bugs which result in incorrect handling of the UPDATE_DISCONNECTED option when
-#       using the URL download method or when specifying a SOURCE_DIR with no download
-#       method. Fixes for these have been created, the last of which is scheduled for
-#       inclusion in CMake 3.8.0. Details can be found here:
-#
-#           https://gitlab.kitware.com/cmake/cmake/commit/bdca68388bd57f8302d3c1d83d691034b7ffa70c
-#           https://gitlab.kitware.com/cmake/cmake/issues/16428
-#
-#       If you experience build errors related to the update step, consider avoiding
-#       the use of UPDATE_DISCONNECTED.
-#
-# EXAMPLE USAGE:
-#
-#   include(DownloadProject)
-#   download_project(PROJ                googletest
-#                    GIT_REPOSITORY      https://github.com/google/googletest.git
-#                    GIT_TAG             master
-#                    UPDATE_DISCONNECTED 1
-#                    QUIET
-#   )
-#
-#   add_subdirectory(${googletest_SOURCE_DIR} ${googletest_BINARY_DIR})
-#
-#========================================================================================
-
-
-set(_DownloadProjectDir "${CMAKE_CURRENT_LIST_DIR}")
-
-include(CMakeParseArguments)
-
-function(download_project)
-
-    set(options QUIET)
-    set(oneValueArgs
-        PROJ
-        PREFIX
-        DOWNLOAD_DIR
-        SOURCE_DIR
-        BINARY_DIR
-        # Prevent the following from being passed through
-        CONFIGURE_COMMAND
-        BUILD_COMMAND
-        INSTALL_COMMAND
-        TEST_COMMAND
-    )
-    set(multiValueArgs "")
-
-    cmake_parse_arguments(DL_ARGS "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-
-    # Hide output if requested
-    if (DL_ARGS_QUIET)
-        set(OUTPUT_QUIET "OUTPUT_QUIET")
-    else()
-        unset(OUTPUT_QUIET)
-        message(STATUS "Downloading/updating ${DL_ARGS_PROJ}")
-    endif()
-
-    # Set up where we will put our temporary CMakeLists.txt file and also
-    # the base point below which the default source and binary dirs will be.
-    # The prefix must always be an absolute path.
-    if (NOT DL_ARGS_PREFIX)
-        set(DL_ARGS_PREFIX "${CMAKE_BINARY_DIR}")
-    else()
-        get_filename_component(DL_ARGS_PREFIX "${DL_ARGS_PREFIX}" ABSOLUTE
-                               BASE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
-    endif()
-    if (NOT DL_ARGS_DOWNLOAD_DIR)
-        set(DL_ARGS_DOWNLOAD_DIR "${DL_ARGS_PREFIX}/${DL_ARGS_PROJ}-download")
-    endif()
-
-    # Ensure the caller can know where to find the source and build directories
-    if (NOT DL_ARGS_SOURCE_DIR)
-        set(DL_ARGS_SOURCE_DIR "${DL_ARGS_PREFIX}/${DL_ARGS_PROJ}-src")
-    endif()
-    if (NOT DL_ARGS_BINARY_DIR)
-        set(DL_ARGS_BINARY_DIR "${DL_ARGS_PREFIX}/${DL_ARGS_PROJ}-build")
-    endif()
-    set(${DL_ARGS_PROJ}_SOURCE_DIR "${DL_ARGS_SOURCE_DIR}" PARENT_SCOPE)
-    set(${DL_ARGS_PROJ}_BINARY_DIR "${DL_ARGS_BINARY_DIR}" PARENT_SCOPE)
-
-    # The way that CLion manages multiple configurations, it causes a copy of
-    # the CMakeCache.txt to be copied across due to it not expecting there to
-    # be a project within a project.  This causes the hard-coded paths in the
-    # cache to be copied and builds to fail.  To mitigate this, we simply
-    # remove the cache if it exists before we configure the new project.  It
-    # is safe to do so because it will be re-generated.  Since this is only
-    # executed at the configure step, it should not cause additional builds or
-    # downloads.
-    file(REMOVE "${DL_ARGS_DOWNLOAD_DIR}/CMakeCache.txt")
-
-    # Create and build a separate CMake project to carry out the download.
-    # If we've already previously done these steps, they will not cause
-    # anything to be updated, so extra rebuilds of the project won't occur.
-    # Make sure to pass through CMAKE_MAKE_PROGRAM in case the main project
-    # has this set to something not findable on the PATH.
-    configure_file("${_DownloadProjectDir}/DownloadProject.CMakeLists.cmake.in"
-                   "${DL_ARGS_DOWNLOAD_DIR}/CMakeLists.txt")
-    execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}"
-                        -D "CMAKE_MAKE_PROGRAM:FILE=${CMAKE_MAKE_PROGRAM}"
-                        .
-                    RESULT_VARIABLE result
-                    ${OUTPUT_QUIET}
-                    WORKING_DIRECTORY "${DL_ARGS_DOWNLOAD_DIR}"
-    )
-    if(result)
-        message(FATAL_ERROR "CMake step for ${DL_ARGS_PROJ} failed: ${result}")
-    endif()
-    execute_process(COMMAND ${CMAKE_COMMAND} --build .
-                    RESULT_VARIABLE result
-                    ${OUTPUT_QUIET}
-                    WORKING_DIRECTORY "${DL_ARGS_DOWNLOAD_DIR}"
-    )
-    if(result)
-        message(FATAL_ERROR "Build step for ${DL_ARGS_PROJ} failed: ${result}")
-    endif()
-
-endfunction()

cmake/testing.cmake

@@ -0,0 +1,22 @@
+
+function(ASSERT_EQUAL)
+  if (NOT ARGC EQUAL 2) 
+    message(FATAL_ERROR "assertion failed: invalid argument count: ${ARGC}")
+  endif()
+
+  if (NOT ${ARGV0} STREQUAL ${ARGV1})
+    message(FATAL_ERROR "assertion failed: '${ARGV0}' != '${ARGV1}'")
+  else()
+    message(STATUS "test passed: '${ARGV0}' == '${ARGV1}'")
+  endif()
+endfunction()
+
+function(ASSERT_EMPTY)
+  if (NOT ARGC EQUAL 0) 
+    message(FATAL_ERROR "assertion failed: input ${ARGC} not empty: '${ARGV}'")
+  endif()
+endfunction()
+
+function(ASSERTION_FAILED)
+  message(FATAL_ERROR "assertion failed: ${ARGN}")
+endfunction()

examples/benchmark/CMakeLists.txt

@@ -0,0 +1,32 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleBenchmark)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME fibonacci
+  GIT_REPOSITORY https://github.com/TheLartians/Fibonacci.git
+  VERSION 2.0
+)
+
+CPMAddPackage(
+  NAME benchmark
+  GITHUB_REPOSITORY google/benchmark
+  VERSION 1.5.0
+  OPTIONS
+    "BENCHMARK_ENABLE_TESTING Off"
+)
+
+if (benchmark_ADDED)
+  # patch google benchmark target
+  set_target_properties(benchmark PROPERTIES CXX_STANDARD 17)
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMExampleBenchmark "main.cpp")
+set_target_properties(CPMExampleBenchmark PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMExampleBenchmark fibonacci benchmark)

examples/benchmark/main.cpp

@@ -0,0 +1,36 @@
+#include <benchmark/benchmark.h>
+#include <vector>
+#include <algorithm>
+#include <random>
+
+#include <fibonacci.h>
+
+
+std::vector<unsigned> createTestNumbers(){
+  std::vector<unsigned> v;
+  for (int i=0;i<25;++i) v.emplace_back(i);
+  std::random_device rd;
+  std::mt19937 g(rd());
+  std::shuffle(v.begin(), v.end(), g);
+  return v;
+}
+
+void fibonacci(benchmark::State& state) {
+  auto numbers = createTestNumbers();
+  for (auto _ : state) {
+    for (auto v: numbers) benchmark::DoNotOptimize(fibonacci(v));
+  }
+}
+
+BENCHMARK(fibonacci);
+
+void fastFibonacci(benchmark::State& state) {
+  auto numbers = createTestNumbers();
+  for (auto _ : state) {
+    for (auto v: numbers) benchmark::DoNotOptimize(fastFibonacci(v));
+  }
+}
+
+BENCHMARK(fastFibonacci);
+
+BENCHMARK_MAIN();

examples/boost/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleBoost)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleBoost main.cpp)
+set_target_properties(CPMExampleBoost PROPERTIES CXX_STANDARD 17)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMFindPackage(
+  NAME Boost
+  GITHUB_REPOSITORY Orphis/boost-cmake
+  VERSION 1.67.0
+  FIND_PACKAGE_ARGUMENTS "COMPONENTS system"
+)
+
+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/build_all.py

@@ -0,0 +1,29 @@
+#!/usr/bin/python3
+
+from pathlib import Path
+from subprocess import PIPE, run
+
+examples = [
+  x for x in Path(__file__).parent.iterdir() if x.is_dir() and (x / 'CMakeLists.txt').exists()
+]
+
+assert(len(examples) > 0)
+
+def runCommand(command):
+  print('- %s' % command)
+  result = run(command, stdout=PIPE, stderr=PIPE, universal_newlines=True, shell=True)
+  if result.returncode != 0:
+    print("error while running '%s':\n" % command, '  ' + str(result.stderr).replace('\n','\n  '))
+    exit(result.returncode)
+  return result.stdout
+
+print('')
+for example in examples:
+  print("running example %s" % example.name)
+  print("================" + ('=' * len(example.name)))
+  project = Path(".") / 'build' / example.name
+  configure = runCommand('cmake -H%s -B%s' % (example, project))
+  print('  ' + '\n  '.join([line for line in configure.split('\n') if 'CPM:' in line]))
+  build = runCommand('cmake --build %s -j4' % (project))
+  print('  ' + '\n  '.join([line for line in build.split('\n') if 'Built target' in line]))
+  print('')

examples/catch2/CMakeLists.txt

@@ -0,0 +1,41 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleCatch2)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME fibonacci
+  GIT_REPOSITORY https://github.com/TheLartians/Fibonacci.git
+  VERSION 2.0
+)
+
+CPMAddPackage(
+  NAME Catch2
+  GITHUB_REPOSITORY catchorg/Catch2
+  VERSION 2.5.0
+)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleCatch2 main.cpp)
+target_link_libraries(CPMExampleCatch2 fibonacci Catch2)
+set_target_properties(CPMExampleCatch2 PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")
+
+# ---- Enable testing ----
+
+ENABLE_TESTING() 
+ADD_TEST(CPMExampleCatch2 CPMExampleCatch2)
+
+# ---- Add code coverage ----
+
+if (${ENABLE_TEST_COVERAGE})
+  set_target_properties(CPMExampleCatch2 PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
+  target_link_options(CPMExampleCatch2 PUBLIC "--coverage")
+endif()

examples/catch2/main.cpp

@@ -0,0 +1,20 @@
+#define CATCH_CONFIG_MAIN
+
+#include <catch2/catch.hpp>
+#include <fibonacci.h>
+
+TEST_CASE("fibonacci"){
+  REQUIRE(fibonacci(0) == 0);
+  REQUIRE(fibonacci(1) == 1);
+  REQUIRE(fibonacci(2) == 1);
+  REQUIRE(fibonacci(3) == 2);
+  REQUIRE(fibonacci(4) == 3);
+  REQUIRE(fibonacci(5) == 5);
+  REQUIRE(fibonacci(13) == 233);
+}
+
+TEST_CASE("fastFibonacci"){
+  for (unsigned i=0; i<25; ++i){
+    REQUIRE(fibonacci(i) == fastFibonacci(i));
+  }
+}

examples/cereal/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleCereal)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME cereal
+  VERSION 1.2.2
+  GITHUB_REPOSITORY USCiLab/cereal
+  OPTIONS
+    "SKIP_PORTABILITY_TEST ON"
+    "JUST_INSTALL_CEREAL ON"
+)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleCereal main.cpp)
+target_link_libraries(CPMExampleCereal cereal )
+set_target_properties(CPMExampleCereal PROPERTIES CXX_STANDARD 17)

examples/cereal/main.cpp

@@ -0,0 +1,34 @@
+#define CATCH_CONFIG_MAIN
+
+#include <cereal/cereal.hpp>
+#include <cereal/archives/json.hpp>
+
+#include <string>
+#include <sstream>
+
+struct player_data 
+{
+  int id{-1};
+  std::string name{};
+};
+
+template<typename Archive>
+void serialize(Archive& archive, player_data const &data)
+{
+  archive(
+    cereal::make_nvp("id", data.id), 
+    cereal::make_nvp("name", data.name)
+  );
+}
+
+int main(int argc, char const *argv[])
+{
+  player_data player{3, "Gamer One"};
+  std::ostringstream oss;
+  cereal::JSONOutputArchive output(oss);
+  output(cereal::make_nvp("player_data", player));
+
+  std::cout << oss.str() << std::endl;
+
+  return 0;
+}

examples/cxxopts/CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleCXXOpts)
+
+# ---- 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

@@ -0,0 +1,41 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleDoctest)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME fibonacci
+  GIT_REPOSITORY https://github.com/TheLartians/Fibonacci.git
+  VERSION 2.0
+)
+
+CPMAddPackage(
+  NAME doctest
+  GITHUB_REPOSITORY onqtam/doctest
+  GIT_TAG 2.3.2
+)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleDoctest main.cpp)
+target_link_libraries(CPMExampleDoctest fibonacci doctest)
+set_target_properties(CPMExampleDoctest PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")
+
+# ---- Enable testing ----
+
+ENABLE_TESTING() 
+ADD_TEST(CPMExampleDoctest CPMExampleDoctest)
+
+# ---- Add code coverage ----
+
+if (${ENABLE_TEST_COVERAGE})
+  set_target_properties(CPMExampleDoctest PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
+  target_link_options(CPMExampleDoctest PUBLIC "--coverage")
+endif()

examples/doctest/main.cpp

@@ -0,0 +1,20 @@
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+
+#include <doctest/doctest.h>
+#include <fibonacci.h>
+
+TEST_CASE("fibonacci"){
+  CHECK(fibonacci(0) == 0);
+  CHECK(fibonacci(1) == 1);
+  CHECK(fibonacci(2) == 1);
+  CHECK(fibonacci(3) == 2);
+  CHECK(fibonacci(4) == 3);
+  CHECK(fibonacci(5) == 5);
+  CHECK(fibonacci(13) == 233);
+}
+
+TEST_CASE("fastfibonacci"){
+  for (unsigned i=0; i<25; ++i){
+    CHECK(fibonacci(i) == fastFibonacci(i));
+  }
+}

examples/entt/CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMEnTTExample)
+
+# ---- 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/fmt/CMakeLists.txt

@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMJSONExample)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME fmt
+  GIT_TAG 6.1.2
+  GITHUB_REPOSITORY fmtlib/fmt
+)
+
+# ---- Executable ----
+
+add_executable(CPMFmtExample "main.cpp")
+set_target_properties(CPMFmtExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMFmtExample fmt)

examples/fmt/main.cpp

@@ -0,0 +1,6 @@
+#include <fmt/format.h>
+
+int main(){
+  fmt::print("Hello, {}!\n", "world");
+  return 0;
+}

examples/gtest/CMakeLists.txt

@@ -0,0 +1,45 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleGtest)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME fibonacci
+  GIT_REPOSITORY https://github.com/TheLartians/Fibonacci.git
+  VERSION 2.0
+)
+
+CPMAddPackage(
+  NAME googletest
+  GITHUB_REPOSITORY google/googletest
+  GIT_TAG release-1.8.1
+  VERSION 1.8.1
+  OPTIONS
+      "INSTALL_GTEST OFF"
+      "gtest_force_shared_crt"
+)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleGtest main.cpp)
+target_link_libraries(CPMExampleGtest fibonacci gtest gtest_main gmock)
+set_target_properties(CPMExampleGtest PROPERTIES CXX_STANDARD 17)
+
+# ---- Enable testing ----
+
+enable_testing() 
+add_test(CPMExampleGtest CPMExampleGtest)
+
+# ---- Add code coverage ----
+
+if (${ENABLE_TEST_COVERAGE})
+  set_target_properties(CPMExampleGtest PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
+  target_link_options(CPMExampleGtest PUBLIC "--coverage")
+endif()

examples/gtest/main.cpp

@@ -0,0 +1,13 @@
+#include <gtest/gtest.h>
+#include <fibonacci.h>
+
+TEST(FibonacciTests, BasicChecks)
+{
+  ASSERT_TRUE(fibonacci(0) == 0);
+  ASSERT_TRUE(fibonacci(1) == 1);
+  ASSERT_TRUE(fibonacci(2) == 1);
+  ASSERT_TRUE(fibonacci(3) == 2);
+  ASSERT_TRUE(fibonacci(4) == 3);
+  ASSERT_TRUE(fibonacci(5) == 5);
+  ASSERT_TRUE(fibonacci(13) == 233);
+}

examples/json/CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMJSONExample)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME nlohmann_json
+  VERSION 3.6.1  
+  # not using the repo as it takes forever to clone
+  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)
+  target_include_directories(nlohmann_json INTERFACE ${nlohmann_json_SOURCE_DIR})
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMJSONExample "main.cpp")
+set_target_properties(CPMJSONExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMJSONExample nlohmann_json)

examples/json/main.cpp

@@ -0,0 +1,25 @@
+#include <nlohmann/json.hpp>
+#include <iostream>
+#include <iomanip>
+
+int main(){
+  
+  nlohmann::json json = {
+    {"pi", 3.141},
+    {"happy", true},
+    {"name", "Niels"},
+    {"nothing", nullptr},
+    {"answer", {
+      {"everything", 42}
+    }},
+    {"list", {1, 0, 2}},
+    {"object", {
+      {"currency", "USD"},
+      {"value", 42.99}
+    }}
+  };
+
+  std::cout << "declared JSON object: " << std::setw(2) << json << std::endl;
+
+  return 0;
+}

examples/linenoise/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMlinenoiseExample)
+
+# ---- 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/range-v3/CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMRangev3Example)
+
+# ---- 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/simple_match/CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMSimpleMatchExample)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME simple_match
+  GIT_REPOSITORY https://github.com/jbandela/simple_match.git
+  GIT_TAG a3ab17f3d98db302de68ad85ed399a42ae41889e
+  DOWNLOAD_ONLY True
+)
+
+if(simple_match_ADDED)
+  add_library(simple_match INTERFACE IMPORTED)
+  target_include_directories(simple_match INTERFACE "${simple_match_SOURCE_DIR}/include")
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMSimpleMatchExample "main.cpp")
+set_target_properties(CPMSimpleMatchExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMSimpleMatchExample simple_match)
+

examples/simple_match/main.cpp

@@ -0,0 +1,34 @@
+#include <simple_match/simple_match.hpp>
+
+#include <iostream>
+
+int main(int argc, char ** argv){
+  using namespace simple_match;
+  using namespace simple_match::placeholders;
+
+  std::string input;
+  std::cout << "please enter a number or 'quit' to exit" << std::endl;
+
+  while (true) {
+    std::cout << "> ";
+    std::getline(std::cin, input);
+    if (input == "quit") { break; }
+    int x;
+    try {
+      x = std::stoi(input);
+    } catch(std::invalid_argument &) {
+      std::cout << "invalid input" << std::endl;
+      continue;
+    }
+    
+    match(x,
+      1, []() {std::cout << "The answer is one\n"; },
+      2, []() {std::cout << "The answer is two\n"; },
+      _x < 10, [](auto&& a) {std::cout << "The answer " << a << " is less than 10\n"; },
+      10 < _x < 20,	[](auto&& a) {std::cout << "The answer " << a  << " is between 10 and 20 exclusive\n"; },
+      _, []() {std::cout << "Did not match\n"; }
+    );
+  }
+
+  return 0;
+}

examples/sol2/CMakeLists.txt

@@ -0,0 +1,47 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMSol2Example)
+
+# ---- 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);
+}

examples/yaml/CMakeLists.txt

@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMYamlExample)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME yaml-cpp
+  GIT_REPOSITORY https://github.com/jbeder/yaml-cpp.git
+  # 0.6.2 uses deprecated CMake syntax
+  VERSION 0.6.3                                  
+  # 0.6.3 is not released yet, so use the most recent commit
+  GIT_TAG 012269756149ae99745b6dafefd415843d7420bb 
+  OPTIONS
+    "YAML_CPP_BUILD_TESTS Off"
+    "YAML_CPP_BUILD_CONTRIB Off"
+    "YAML_CPP_BUILD_TOOLS Off"
+)
+
+# ---- Executable ----
+
+add_executable(CPMYamlExample "main.cpp")
+set_target_properties(CPMYamlExample PROPERTIES CXX_STANDARD 17)        
+target_link_libraries(CPMYamlExample yaml-cpp)
+

examples/yaml/main.cpp

@@ -0,0 +1,14 @@
+#include <yaml-cpp/yaml.h>
+#include <iostream>
+
+int main(int argc, char ** argv){
+  if (argc != 2) {
+    std::cout << "usage: " << argv[0] << " <path to yaml file>" << std::endl;
+    return 1;
+  }
+
+  YAML::Node config = YAML::LoadFile(argv[1]);
+  std::cout << "Parsed YAML:\n" << config << std::endl;
+
+  return 0;
+}

examples/yaml/monsters.yaml

@@ -0,0 +1,21 @@
+- name: Ogre
+  position: [0, 5, 0]
+  powers:
+    - name: Club
+      damage: 10
+    - name: Fist
+      damage: 8
+- name: Dragon
+  position: [1, 0, 10]
+  powers:
+    - name: Fire Breath
+      damage: 25
+    - name: Claws
+      damage: 15
+- name: Wizard
+  position: [5, -3, 0]
+  powers:
+    - name: Acid Rain
+      damage: 50
+    - name: Staff
+      damage: 3

test/CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMTests)
+
+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()
+
+add_custom_target(test-verbose COMMAND ${CMAKE_CTEST_COMMAND} -C Debug --verbose)

test/unit/cache.cmake

@@ -0,0 +1,121 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+include(${CPM_PATH}/testing.cmake)
+include(CMakePackageConfigHelpers)
+
+
+set(CPM_SOURCE_CACHE_DIR "${CMAKE_CURRENT_BINARY_DIR}/CPM")
+set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/cache)
+
+function(clear_cache)
+  FILE(REMOVE_RECURSE ${CPM_SOURCE_CACHE_DIR})
+  
+  if (EXISTS "${CPM_SOURCE_CACHE_DIR}")
+    ASSERTION_FAILED("cache not cleared")
+  endif()
+endfunction()
+
+function(update_cmake_lists)
+  configure_package_config_file(
+    "${CMAKE_CURRENT_LIST_DIR}/cache/CMakeLists.txt.in"
+    "${CMAKE_CURRENT_LIST_DIR}/cache/CMakeLists.txt"
+    INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/junk
+  )
+endfunction()
+
+function(reset_test)
+  clear_cache()
+  FILE(REMOVE_RECURSE ${TEST_BUILD_DIR})
+  update_cmake_lists()
+endfunction()
+
+set(FIBONACCI_VERSION 1.0)
+
+## Read CPM_SOURCE_CACHE from arguments
+
+reset_test()
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/cache" "-B${TEST_BUILD_DIR}" "-DCPM_SOURCE_CACHE=${CPM_SOURCE_CACHE_DIR}"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+
+if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
+  ASSERTION_FAILED("fibonacci not in cache")
+endif()
+
+FILE(GLOB FIBONACCI_VERSIONs "${CPM_SOURCE_CACHE_DIR}/fibonacci/*")
+list(LENGTH FIBONACCI_VERSIONs FIBONACCI_VERSION_count)
+ASSERT_EQUAL(${FIBONACCI_VERSION_count} "1")
+
+FILE(GLOB fibonacci_versions "${CPM_SOURCE_CACHE_DIR}/fibonacci/*")
+list(LENGTH fibonacci_versions fibonacci_version_count)
+ASSERT_EQUAL(${fibonacci_version_count} "1")
+
+## Update dependency and keep CPM_SOURCE_CACHE
+
+set(FIBONACCI_VERSION 2.0)
+update_cmake_lists()
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} ${TEST_BUILD_DIR}
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+
+FILE(GLOB FIBONACCI_VERSIONs "${CPM_SOURCE_CACHE_DIR}/fibonacci/*")
+list(LENGTH FIBONACCI_VERSIONs FIBONACCI_VERSION_count)
+ASSERT_EQUAL(${FIBONACCI_VERSION_count} "2")
+
+## Clear cache and update
+
+clear_cache()
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} ${TEST_BUILD_DIR}
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+
+if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
+  ASSERTION_FAILED("fibonacci not in cache")
+endif()
+
+## Read CPM_SOURCE_CACHE from environment
+
+reset_test()
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} -E env "CPM_SOURCE_CACHE=${CPM_SOURCE_CACHE_DIR}" ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/cache" "-B${TEST_BUILD_DIR}"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+
+if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
+  ASSERTION_FAILED("fibonacci not in cache")
+endif()
+
+## Overwrite CPM_SOURCE_CACHE with argument
+
+reset_test()
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} -E env "CPM_SOURCE_CACHE=${CMAKE_CURRENT_BINARY_DIR}/junk" ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/cache" "-B${TEST_BUILD_DIR}" "-DCPM_SOURCE_CACHE=${CPM_SOURCE_CACHE_DIR}"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")
+
+if (NOT EXISTS "${CPM_SOURCE_CACHE_DIR}/fibonacci")
+  ASSERTION_FAILED("fibonacci not in cache")
+endif()

test/unit/cache/.gitignore

@@ -0,0 +1 @@
+/CMakeLists.txt

test/unit/cache/CMakeLists.txt.in

@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleCatch2)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(@CPM_PATH@/CPM.cmake)
+
+CPMAddPackage(
+  NAME fibonacci
+  GIT_REPOSITORY https://github.com/TheLartians/Fibonacci.git
+  VERSION @FIBONACCI_VERSION@
+)
+
+# ---- Create binary ----
+
+add_executable(CPMExampleCatch2 main.cpp)
+target_link_libraries(CPMExampleCatch2 fibonacci)
+set_target_properties(CPMExampleCatch2 PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")

test/unit/cache/main.cpp

@@ -0,0 +1,9 @@
+#define CATCH_CONFIG_MAIN
+
+#include <fibonacci.h>
+#include <iostream>
+
+int main(){
+  std::cout << "fib(10) = " << fastFibonacci(10) << std::endl;
+  return 0;
+}

test/unit/dependency_properties.cmake

@@ -0,0 +1,41 @@
+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
+)
+
+CPMAddPackage(
+  NAME A
+  VERSION 1.2.3
+)
+
+CPMGetPackageVersion(A VERSION)
+ASSERT_EQUAL(${VERSION} "1.2.3")
+
+CPMAddPackage(
+  NAME B
+  VERSION 2.4.1
+)
+
+CPMAddPackage(
+  NAME B
+  GIT_TAG v2.3.1
+)
+
+CPMGetPackageVersion(B VERSION)
+ASSERT_EQUAL(${VERSION} "2.4.1")
+
+CPMAddPackage(
+  NAME C
+  GIT_TAG v3.1.2-a
+  VERSION 3.1.2
+)
+
+CPMGetPackageVersion(C VERSION)
+ASSERT_EQUAL(${VERSION} "3.1.2")

test/unit/source_dir.cmake

@@ -0,0 +1,19 @@
+
+include(CMakePackageConfigHelpers)
+include(${CPM_PATH}/testing.cmake)
+
+set(TEST_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/source_dir)
+
+configure_package_config_file(
+  "${CMAKE_CURRENT_LIST_DIR}/source_dir/CMakeLists.txt.in"
+  "${CMAKE_CURRENT_LIST_DIR}/source_dir/CMakeLists.txt"
+  INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/junk
+)
+
+execute_process(
+  COMMAND 
+  ${CMAKE_COMMAND} "-H${CMAKE_CURRENT_LIST_DIR}/source_dir" "-B${TEST_BUILD_DIR}"
+  RESULT_VARIABLE ret
+)
+
+ASSERT_EQUAL(${ret} "0")

test/unit/source_dir/.gitignore

@@ -0,0 +1 @@
+/CMakeLists.txt

test/unit/source_dir/CMakeLists.txt.in

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleCatch2)
+
+# ---- Options ----
+
+option(ENABLE_TEST_COVERAGE "Enable test coverage" OFF)
+
+# ---- Dependencies ----
+
+include(@CPM_PATH@/CPM.cmake)
+
+CPMAddPackage(
+  NAME Dependency
+  SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/dependency
+)
+
+# ---- Call dependency method to validate correct addition of directory ----
+
+dependency_function()

test/unit/source_dir/dependency/CMakeLists.txt

@@ -0,0 +1,4 @@
+
+function(dependency_function)
+  message("called external method")
+endfunction()

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})

tests/complex/CMakeLists.txt

@@ -1,41 +0,0 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
-project(CPMTest)
-
-include(${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/CPM.cmake)
-
-CPMAddPackage(
-  NAME LHC
-  GIT_REPOSITORY https://github.com/TheLartians/LHC.git
-  VERSION 0.3
-)
-
-CPMAddPackage(
-  NAME LarsEvent
-  GIT_REPOSITORY https://github.com/TheLartians/Event.git
-  VERSION 1.0
-  GIT_TAG master
-)
-
-# Add project that depends on previous project
-CPMAddPackage(
-  NAME LarsParser
-  GIT_REPOSITORY https://github.com/TheLartians/Parser.git
-  VERSION 1.3
-)
-
-# add project twice
-CPMAddPackage(
-  NAME LHC
-  GIT_REPOSITORY https://github.com/TheLartians/LHC.git
-  VERSION 0.3
-)
-
-# add executable
-set (CMAKE_CXX_STANDARD 17)
-add_executable(cpm-test test.cpp)
-target_link_libraries(cpm-test LHC LarsEvent LarsParser)
-
-# tests
-enable_testing()
-add_test(cpm-test cpm-test)

tests/complex/test.cpp

@@ -1,32 +0,0 @@
-#include <lars/parser_generator.h>
-#include <lars/event.h>
-
-int main() {
-  // Define the return value
-  int result = 1;
-
-  // Define grammar and evaluation rules
-  lars::ParserGenerator<float> g;
-  g.setSeparator(g["Whitespace"] << "[\t ]");
-  g["Sum"     ] << "Add | Subtract | Product";
-  g["Product" ] << "Multiply | Divide | Atomic";
-  g["Atomic"  ] << "Number | '(' Sum ')'";
-  g["Add"     ] << "Sum '+' Product"    >> [](auto e){ return e[0].evaluate() + e[1].evaluate(); };
-  g["Subtract"] << "Sum '-' Product"    >> [](auto e){ return e[0].evaluate() - e[1].evaluate(); };
-  g["Multiply"] << "Product '*' Atomic" >> [](auto e){ return e[0].evaluate() * e[1].evaluate(); };
-  g["Divide"  ] << "Product '/' Atomic" >> [](auto e){ return e[0].evaluate() / e[1].evaluate(); };
-  g["Number"  ] << "'-'? [0-9]+ ('.' [0-9]+)?" >> [](auto e){ return stof(e.string()); };
-  g.setStart(g["Sum"]);
-
-  // Execute a string
-
-  // create an event
-  lars::Event<float> onResult;
-  onResult.connect([&](float v){ result = !(int(v) == 5); });
-  
-  // emit the result of a parsed string
-  onResult.notify(g.run("1 + 2 * (3+4)/2 - 3"));
-
-  // return the result
-  return result;
-}

tests/simple/CMakeLists.txt

@@ -1,21 +0,0 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
-
-project(CPMTest)
-
-# add dependencies
-include(${CMAKE_CURRENT_SOURCE_DIR}/../../cmake/CPM.cmake)
-
-CPMAddPackage(
-  NAME LarsParser
-  GIT_REPOSITORY https://github.com/TheLartians/Parser.git
-  VERSION 1.3
-)
-
-# add executable
-set (CMAKE_CXX_STANDARD 17)
-add_executable(cpm-test test.cpp)
-target_link_libraries(cpm-test LarsParser)
-
-# tests
-enable_testing()
-add_test(cpm-test cpm-test)

tests/simple/test.cpp

@@ -1,27 +0,0 @@
-#include <lars/parser_generator.h>
-
-int main() {
-  lars::ParserGenerator<float> g;
-
-  // Define grammar and evaluation rules
-  g.setSeparator(g["Whitespace"] << "[\t ]");
-  g["Sum"     ] << "Add | Subtract | Product";
-  g["Product" ] << "Multiply | Divide | Atomic";
-  g["Atomic"  ] << "Number | '(' Sum ')'";
-  g["Add"     ] << "Sum '+' Product"    >> [](auto e){ return e[0].evaluate() + e[1].evaluate(); };
-  g["Subtract"] << "Sum '-' Product"    >> [](auto e){ return e[0].evaluate() - e[1].evaluate(); };
-  g["Multiply"] << "Product '*' Atomic" >> [](auto e){ return e[0].evaluate() * e[1].evaluate(); };
-  g["Divide"  ] << "Product '/' Atomic" >> [](auto e){ return e[0].evaluate() / e[1].evaluate(); };
-  g["Number"  ] << "'-'? [0-9]+ ('.' [0-9]+)?" >> [](auto e){ return stof(e.string()); };
-  g.setStart(g["Sum"]);
-
-  // Execute a string
-  float result = g.run("1 + 2 * (3+4)/2 - 3");
-
-  // validate result
-  if (result == 5) {
-    return 0;
-  } else {
-    return 1;
-  }
-}