Nix install instructions are outdated/wrong/confusing.

[thomastjeffery]

The information here is confusing, convoluted, and doesn't seem to work.

The real way to build yi with Nix

To build yi in Nix, here is what you currently can do:

1. Set up package overrides in Nix, so yi will build at all
   Put the following in your ~/.config/nixpkgs/config.nix:

{
  packageOverrides = pkgs: {
    haskellPackages = pkgs.haskellPackages.override {
      overrides = self: super: {
        yi-core            = super.yi-core_0_16_0;
        yi-frontend-vty    = super.yi-frontend-vty_0_16_0;
        yi-fuzzy-open      = super.yi-fuzzy-open_0_16_0;
        yi-ireader         = super.yi-ireader_0_16_0;
        yi-keymap-cua      = super.yi-keymap-cua_0_16_0;
        yi-keymap-emacs    = super.yi-keymap-emacs_0_16_0;
        yi-keymap-vim      = super.yi-keymap-vim_0_16_0;
        yi-language        = super.yi-language_0_16_0;
        yi-misc-modes      = super.yi-misc-modes_0_16_0;
        yi-mode-haskell    = super.yi-mode-haskell_0_16_0;
        yi-mode-javascript = super.yi-mode-javascript_0_16_0;
        yi-snippet         = super.yi-snippet_0_16_0;
        yi-rope            = super.yi-rope_0_10;
      };
    };
  };
}

If you don't do this, nix will complain that it has missing dependencies.

2. Copy an example config to the right place

$ cp yi-editor/yi/example-configs/yi-config-that-you-want/* ~/.config/yi/

1. Go to ~/.config/yi/, and build yi.
   You can leave out the -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz if you are already using the master channel. This will not work on another channel like NixOS-17.09.

$ cd ~/.config/yi/
$ nix-shell -p cabal2nix -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz
[nix-shell]$ cabal2nix . > default.nix
[nix-shell]$ cabal2nix --shell . > shell.nix
[nix-shell]$ exit
$ nix-build shell.nix -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz

1. Run yi
   You need to use nix-shell, so yi can rebuild the configuration you made.

$ nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz
[nix-shell]$ ./result/bin/yi

[noughtmare]

Copy an example config to the right place
~$ cp yi-editor/yi/example-configs/yi-config-that-you-want/* ~/.config/yi/

This is not needed by the static configs (which are recommended). They can be placed anywhere you want.

I think the overrides wouldn't have to be added if we would specify version bounds in the cabal files of the example-configs (which is probably a good idea anyway). What errors do you get when you don't specify these overrides in your ~/.config/nixpkgs/config.nix?

Finally, I have seen somewhere that stack is also capable of using nix, so you should be able to run stack --nix build instead of nix-shell -p cabal2nix to build yi.

[thomastjeffery]

This is not needed by the static configs (which are recommended).

This is true, but it works for both. I wanted to be succinct. That is explained in the yi-editor/yi/README.md.

What errors do you get when you don't specify these overrides in your ~/.config/nixpkgs/config.nix?

Nix will try to build the package, and ghc will complain that it can't find the dependencies.

This is explained in more detail here

Finally, I have seen somewhere that stack is also capable of using nix

This is explicitly what I do not want to do.

I don't know what files stack is going to put where. The advantage of Nix is that I am guaranteed a clean functional system. If I want to use Nix, I want to use Nix. Stack is a perfectly fine option, just not the one I am choosing. I don't even have stack installed. I also want to rely on the prebuilt packages that Nix provides.

[noughtmare]

I've changed my own config so that it now build with nix:

$ git clone https://github.com/noughtmare/yi-config.git
$ cabal2nix . --shell > shell.nix
$ nix-build shell.nix

This should work without any overrides.

[thomastjeffery]

That works for me, even using 17.09 instead of master.

[noughtmare]

I think the explicit bounds on the versions of the dependencies helped in this case, so I will also try to fix the example-configs when I have the time.

[noughtmare]

I found another terrible problem, yi-dynamic-configuration is version 0.16.0 on nixpkgs, and the rest of the yi related packages are still on 0.14 so that causes major breakage, because yi-dynamic-configuration-0.16.0 requires yi-core-0.16.0 which is not included in the nixpkgs. So every dynamic configuration is broken on nix.

[noughtmare]

Using the example configs from yi-editor/yi#1043 should also work now (except for the dynamic configs).

[thomastjeffery]

My first comment was just how to get an example config to build using Nix. Here is how to start hacking on yi with Nix.

Hacking Yi with Nix

Here are the steps to set up a build environment using Nix for hacking Yi:

1. Get yi source

mkdir yi-source
cd yi-source
git clone https://github.com/yi-editor/yi
git clone https://github.com/yi-rope

2. Make a default.nix for every yi library

cd yi

for f in yi-*
do
    cd $f
    nix-shell -p cabal2nix --command "cabal2nix . > default.nix"
    cd ..
done

cd ../yi-rope

nix-shell -p cabal2nix --command "cabal2nix . > default.nix"

3. Override Nix packages
   There are a few ways to do this. I like to put the following in my `~/.config/nixpkgs/config.nix

Note that I have both yi-editor/yi and yi-editor/yi-rope checked out to ~/yi-source/. Change those two paths accordingly:

let yi-source-root = ~/yi-source/yi;
    yi-rope-source = ~/yi-source/yi-rope;
in
    {
      packageOverrides = pkgs: {
        haskellPackages = pkgs.haskellPackages.override {
          overrides = self: super: {
            yi-core            = self.callPackage (yi-source-root + /yi-core/default.nix) {};
            yi-frontend-vty    = self.callPackage (yi-source-root + /yi-frontend-vty/default.nix) {};
            yi-frontend-pango  = self.callPackage (yi-source-root + /yi-frontend-pango/default.nix) {};
            yi-fuzzy-open      = self.callPackage (yi-source-root + /yi-fuzzy-open/default.nix) {};
            yi-ireader         = self.callPackage (yi-source-root + /yi-ireader/default.nix) {};
            yi-keymap-cua      = self.callPackage (yi-source-root + /yi-keymap-cua/default.nix) {};
            yi-keymap-emacs    = self.callPackage (yi-source-root + /yi-keymap-emacs/default.nix) {};
            yi-keymap-vim      = self.callPackage (yi-source-root + /yi-keymap-vim/default.nix) {};
            yi-language        = self.callPackage (yi-source-root + /yi-language/default.nix) {};
            yi-misc-modes      = self.callPackage (yi-source-root + /yi-misc-modes/default.nix) {};
            yi-mode-haskell    = self.callPackage (yi-source-root + /yi-mode-haskell/default.nix) {};
            yi-mode-javascript = self.callPackage (yi-source-root + /yi-mode-javascript/default.nix) {};
            yi-snippet         = self.callPackage (yi-source-root + /yi-snippet/default.nix) {};
            yi-rope            = self.callPackage (yi-rope-source + /default.nix) {};
          };
        };
      };
    }

Now you should be able to build yi like usual.

To test this, you can type

nix-shell -p yi

and Nix will build the default configuration from your newly overridden packages, resulting in a shell with your new yi in its path.

You can also build your config just like before, but now Nix will use your overridden packages.

[noughtmare]

It should probably also be mentioned that the *.cabal files need to be generated with hpack.

Also you could probably override the packages in the .nix file of your own config instead of in the global config.nix file.