envs/dev: restructure rust

environments/dev/rust/default.nix

@@ -0,0 +1,32 @@
+{ gitpkgs ? import /home/steveej/src/github/NixOS/nixpkgs {}
+, pkgs ? gitpkgs
+, name ? "generic"
+, version ? "Stable"
+, extraBuildInputs ? []
+}: 
+let 
+  rustPackages = builtins.getAttr "rust${version}" pkgs;
+  rustc = rustPackages.rustc;
+  rustShellHook = { rustc, name }: ''
+    rustname=rust_${rustc.version}_${name}
+    setPS1 $rustname
+    unset name
+  '';
+  commonVimRC = ''
+  '';
+in pkgs.stdenv.mkDerivation {
+  inherit name;
+  buildInputs = with rustPackages;[
+    ( import ./vim-rust.nix { pkgs=gitpkgs; commonRC=commonVimRC;
+        inherit rustc;
+        racerd=pkgs.rustracerd;
+    })
+    rustc cargo
+  ] ++ [
+    pkgs.rustfmt
+  ] ++ extraBuildInputs;
+  shellHook = (rustShellHook){
+    inherit name;
+    inherit rustc;
+  };
+}