Package repositories

[iboB]

Say we have a function CPMAddPackageRepository which takes a single string argument. If it looks like a local filesystem path, then it's interpreted as a directory. If it looks like a an url to an archive, then it's downloaded and extracted by FetchContent and the resulting directory is used.

This directory is expected to have multiple .cmake files, say like cpmpack-name.cmake. Where each is a recipe for a package (typically a single line like CPMAddPackage(NAME foo GITHUB_REPOSITORY user/foo VERSION 1.2.3))

Then calling CPMAddPackage with a string which is a single word (no spaces, no directory separators) would search for cpmpack-<that word>.cmake in the provided repository directories and include it if found.

The last step could be a bit unpleasant as it would lead to a recursive call to CPMAddPackage, but if we don't like it, we may introduce another function CPMAddRepoPackage, or perhaps something even shorter like just CPM

CPMAddPackageRepository(https://github.com/cpm-cmake/official-repo/releases/download/v2.12.4/cpm-official.zip)
CPMAddPackageRepository(${CMAKE_CURRENT_SOURCE_DIR}/local-packages)

cpm(boost)
cpm(glfw)
cpm(imgui)
cpm(my-assets)
cpm(my-toolchain)

[TheLartians]

Note that this suggestion seems very similar to a suggestion in #213. I definitely see how the package repository can make maintaining a project's dependencies easier. One thing I don't like is that versions are now interdependent, so if you want to update a single package through the repository any dependencies are now updated as well - the repository essentially becomes a static package-lockfile for your project. Also, it will need constant updates from maintainers to support the newest versions.

Personally I think an automated package registry like npm, pip or cargo might be a better solution here. This could be an online database where we could query the CPM.cmake command for each version of each package. It could take a bit more work to setup, but imo would pay off down the road in more flexibility and less maintenance effort.

[flagarde]

this is my small (bad?) solution https://github.com/flagarde/CMakeMM / based on (rewritten) https://github.com/vector-of-bool/CMakeCM