[qudat]

Your example looks great! Indeed I trolled every piece of nix documentation I could find -- it was the only way to figure out what I should be doing.

Here's the simplest example of an utter failure when I tried nix: installing ruby 2.2. It's very possible I did something totally wrong, but when I have to use ruby 2.2 and nix cannot do it, it sort of kills your awesome example of being able to override openssl.

Another extremely frustrating experience was the bifurcation between nix and nixos. Clearly one experience is preferred over the other. So many blogs and docs talk about things like HomeManager and other configurations that are nixos specific.

On top of nixos/nix, there's also shell.nix/flakes. There's just too much development in nix right now to make sense of what's going on.

[soraminazuki]

> when I have to use ruby 2.2 and nix cannot do it

Considering that ruby 2.2 was released in 2014, I can't say I'm surprised. It's too much effort to continue maintaining something so old. But if you really want to use it, you could try using the package definition from an older commit of Nixpkgs:

    let
      nixpkgs1709 = pkgs.fetchFromGitHub {
        owner = "NixOS";
        repo = "nixpkgs";
        rev = "e09c0adc63d10249dac8f90313f91e1050861d3c";
        sha256 = "sha256-Di9D0gvaESV3JmX/kW2uEJ68QDlAke23t19bImTXsJ8=";
      };
    
      pinnedPkgs = import nixpkgs1709 { };
    in
    pinnedPkgs.ruby_2_2

> Another extremely frustrating experience was the bifurcation between nix and nixos.

I'm not sure what you mean. Nix is the package manager while NixOS is an entire distro based on Nix the package manager and its configuration language. They have clear separation of concerns. Keeping it that way has actual benefits too, namely portability. It allows you to use Nix on a wide range of platforms including non-NixOS Linux distros, macOS, and even BSDs to some extent.

> On top of nixos/nix, there's also shell.nix/flakes.

Flakes are currently an experimental feature and not meant for wide use yet. So if you're just getting started with Nix, I'd recommend looking into it later until you're sufficiently comfortable with Nix.

They're not fundamentally different, though. Flakes formalize the conventions for writing Nix expressions to make them more reusable.

[Kaze404]

You don't need NixOS for Home Manager. It's actually the first chapter in the installation section: https://nix-community.github.io/home-manager/index.html#sec-...

[qudat]

Thanks for that clarification. My point was mainly that I was being led down paths that were talking about home manager which was something I didn’t want in my system. Nix, nixos, home manager, flakes, shell.nix … they all do different things and blog articles and documentation mix and march them to create a very confusing ecosystem to navigate.

[mikepurvis]

Flakes are actually part of the piece for how to sanely get access to old versions of things, as your project flake can bring in multiple instances of nixpkgs from different “stable” branches and then pull the specific packages off each one that you need.

[qudat]

Just in this thread I have one person saying that I should avoid flakes and you are telling me it will save me. I think we proved my point.

[mikepurvis]

Fair, fair. A slightly more charitable take might be that flakes solve/streamline a set of problems that are particularly acute for power users, and installing multiple specific versions of software without needing to copy the definitions into your overlay is absolutely a power user move.

[soraminazuki]

Flakes are undeniably useful but it's gated behind an experimental flag and documentation work is ongoing. For now, it just shouldn't be the first point of entry for beginners.

[mikepurvis]

The documentation is the biggest gap for sure. I've only been using Nix for about a year, and I'm using flakes exclusively. Although I don't have direct experience with the legacy system, I could definitely picture it being very frustrating managing inputs via the NIXPATH envvar rather than explicitly with flake locking.

[SkyMarshal]

Did you ever try using Ruby 2.2 in an isolated nix-shell? That's arguably the best feature of nix-shell, to create an isolated environment with only the packages you need for that particular project.