Commit Graph

9 Commits

Author SHA1 Message Date
Jan Tojnar
e35f3c0679
doc: Fix some typos 2017-06-11 22:13:42 +02:00
Carles Pagès
cc779bc421 doc: fix overlays paths
It was not updated with 9d6a55aefd.
2017-04-02 10:11:01 +02:00
Eelco Dolstra
7dacca324d
$NIXPKGS_OVERLAYS -> <nixpkgs-overlays>
The Nix search path is the established mechanism for specifying the
location of Nix expressions, so let's use it instead of adding another
environment variable.
2017-02-01 16:07:54 +01:00
Nicolas B. Pierron
88ba960a6d Fix nixpkgs manual generation, missing para closing tag. 2017-01-16 01:17:33 +01:00
Nicolas B. Pierron
2ad710e70e Fix extra nits from aneeshusa 2017-01-16 01:17:33 +01:00
Nicolas B. Pierron
2d6532b330 Update overlay documentation by following nits from aneeshusa. 2017-01-16 01:17:33 +01:00
Nicolas B. Pierron
51d3c931e1 Replace 'phases' by 'layers' in overlays documentation. 2017-01-16 01:17:33 +01:00
Nicolas B. Pierron
f9da1fa957 Throw an error if NIXPKGS_OVERLAYS is invalid and improve documentation. 2017-01-16 01:17:33 +01:00
Nicolas B. Pierron
f5dfe78a1e Add overlays mechanism to Nixpkgs.
This patch add a new argument to Nixpkgs default expression named "overlays".

By default, the value of the argument is either taken from the environment variable `NIXPKGS_OVERLAYS`,
or from the directory `~/.nixpkgs/overlays/`.  If the environment variable does not name a valid directory
then this mechanism would fallback on the home directory.  If the home directory does not exists it will
fallback on an empty list of overlays.

The overlays directory should contain the list of extra Nixpkgs stages which would be used to extend the
content of Nixpkgs, with additional set of packages.  The overlays, i-e directory, files, symbolic links
are used in alphabetical order.

The simplest overlay which extends Nixpkgs with nothing looks like:

```nix
self: super: {
}
```

More refined overlays can use `super` as the basis for building new packages, and `self` as a way to query
the final result of the fix-point.

An example of overlay which extends Nixpkgs with a small set of packages can be found at:
  https://github.com/nbp/nixpkgs-mozilla/blob/nixpkgs-overlay/moz-overlay.nix

To use this file, checkout the repository and add a symbolic link to
the `moz-overlay.nix` file in `~/.nixpkgs/overlays` directory.
2017-01-16 01:17:33 +01:00