[zimbatm]

If I only look at the language properties then Nix makes sense to me. The fact that Nix is lazily evaluated allows for easy composability. This is used a lot in nixpkgs to allow overrides and build up packaging layers. And because the language is interpreted, only the files that are being used need to be evaluated. It wouldn't be very practical to hold all of nixpkgs in memory. It also allow to do things like dynamically import code from another git repo. And finally, the language only allows side-effects through derivations.

None of the above language have all these properties combined.

[atemerev]

I am only talking about the syntax. Semantically, Nix absolutely rocks.