Hi. I’m learning Julia for the first time. I’'m looking for a way to say in my program “If you don’t already have this package, then get it, but if you do, then just use it”. The issue is that if I just put Pkg.add(“DataStructures”), then it seems to re-load that package from the git repo on ever…

[image] andromodon: How do people get the “Only add if we don’t already have package” functionality in an easy way? Define a project and let the resolver deal with it. See https://julialang.github.io/Pkg.jl/dev/creating-packages/ but the whole manual is worth reading.

Even with Projects, for distributing programs it would be nice if there was a way of checking whether the project has been instantiated yet (I’m actually thinking about the eglot-julia package I’ve been semi-working on). Do you know of a good way of doing this? Just running Pkg.instantiate() every …

I am not aware of a recommended way (a lot of nuts and bolts for distributing Julia programs are WIP), but I would either just make it part of an install script, check for the depot being populated (since I would presumably have the program in its own depot). check for the existence of a fi…

Could you elaborate on how and why you use depots other than the default? The only reason I can come up with is as a hack to avoid precompiling when switching environments. I haven’t used anything but the default depots yet and hadn’t planned on doing so for the eglot-julia integration package.

[image] non-Jedi: Could you elaborate on how and why you use depots other than the default? How: Setting the JULIA_DEPOT_PATH environment variable is a convenient way for me (Linux). There might be others Why: When I do it, it’s usually to test whether something (a global thing, like a wor…

[image] ffevotte: Not sure if it’s useful / clean, but I have this function in some scripts that I use to setup new environments: This is more or less what I ended up doing. [image] Using LanguageServer.jl with eglot in emacs Tooling LanguageServer.jl eglot integra…

[image] non-Jedi: This is more or less what I ended up doing. Yes, I just saw that. Sorry for the noise :pensive:

If I understand your question correctly, Pkg.add("DataStructures") already does what you request automatically. The packages used by any of your projects are shared in the depots (e.g the “~/.julia” folder) so no unnecessary duplication occurs. If someone runs Pkg.add("DataStructures") and the pack…

[image] 00vareladavid: The packages used by any of your projects are shared in the depots (e.g the “~/.julia” folder) so no unnecessary duplication occurs. If someone runs Pkg.add("DataStructures") and the package version already exists in your filesystem, Pkg will just use the existing package …

[image] ffevotte: the registry is updated if a new version of the package is available, this new version is downloaded and installed manifest / project files are updated Since the second bullet is wrong, the last bullet is also wrong. What we could change is perhaps to move the updating of r…

How to add a package but only if it is not already there?

General Usage

non-Jedi November 6, 2019, 9:55pm 8

This is more or less what I ended up doing.

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How to add a package but only if it is not already there?

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