[Nix-dev] Nixpkgs versioning

[Colin Putney]

> On Mar 30, 2016, at 1:55 AM, Jakob Gillich <jakob at gillich.me> wrote:
> 
> FYI npm also uses @ for this purpose (e.g. npm install foo at 1.0). I don't
> think I ever had to escape it (?).

I don’t know about Guix, but with NPM, version names are much more important than they are with nix. NPM uses semver and constraint solving to resolve dependencies based on the version numbers, so the actual x.y.z number attached to a given release is critical. With nix, there’s no central registry of packages, release and their numbers, and we often specify dependencies with a Git rev and hash. We use fixed-output derivations to ensure that we always get the right dependency, so the version number of a given derivation doesn’t matter that much, and often doesn’t exist.

Colin