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author | Eelco Dolstra <e.dolstra@tudelft.nl> | 2008-08-14T14·00+0000 |
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committer | Eelco Dolstra <e.dolstra@tudelft.nl> | 2008-08-14T14·00+0000 |
commit | 9279174dde3e1a450e63e866d2683352dd8238d3 (patch) | |
tree | 05b5b835f143b97d150a37873641fb5d5e9a7075 /tests/lang/eval-okay-if.nix | |
parent | db4f4a842515392a6b40f5c86b2ef885c1278451 (diff) |
* Added an experimental feature suggested by Andres: ellipses ("...")
in attribute set pattern matches. This allows defining a function that takes *at least* the listed attributes, while ignoring additional attributes. For instance, {stdenv, fetchurl, fuse, ...}: stdenv.mkDerivation { ... }; defines a function that requires an attribute set that contains the specified attributes but ignores others. The main advantage is that we can then write in all-packages.nix aefs = import ../bla/aefs pkgs; instead of aefs = import ../bla/aefs { inherit stdenv fetchurl fuse; }; This saves a lot of typing (not to mention not having to update all-packages.nix with purely mechanical changes). It saves as much typing as the "args: with args;" style, but has the advantage that the function arguments are properly declared (not implicit in what the body of the "with" uses).
Diffstat (limited to 'tests/lang/eval-okay-if.nix')
0 files changed, 0 insertions, 0 deletions