Package Feature Request: optional packages with required versions

[kmsquire]

In VideoIO, Images and ImageView are currently listed as requirements.

This is not strictly true--VideoIO will gladly read frames from a video file as Arrays, and Simon Danisch recently posted some code which displayed a movie using GLPlot, which doesn't require either package.

However, if a user wants to use Images or ImageView, there are minimum versions required. So one package feature which would be useful is an optional package with a version requirement.

Thoughts?

Related: #7737

[kmsquire]

@StefanKarpinski, does or will Pkg3 handle this?

[StefanKarpinski]

It doesn't yet but there are some tentative plans for adding support for it.

[KristofferC]

Subsumed by the "glue package" discussion in JuliaLang/Pkg.jl#1285.

[DilumAluthge]

For those trying to click the link on mobile: JuliaLang/Pkg.jl#1285