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nixpkgs/pkgs/lib/trivial.nix
Eelco Dolstra 1ac9dcd24d * Fix eval-release.nix by testing whether all attributes of a
derivation evaluate inside the tryEval.  This catches cases such as
  aufs2-util, which fails due to an assertion in its dependency aufs2.
* Explicitly blacklist "xbursttools" because it gives some
  evaluation error in cross-OpenSSL.  No idea why, probably due to
  some pass-through attribute.

svn path=/nixpkgs/trunk/; revision=23247
2010-08-19 12:37:10 +00:00

26 lines
597 B
Nix

rec {
# Identity function.
id = x: x;
# Constant function.
const = x: y: x;
# Named versions corresponding to some builtin operators.
concat = x: y: x ++ y;
or = x: y: x || y;
and = x: y: x && y;
mergeAttrs = x: y: x // y;
# Take a function and evaluate it with its own returned value.
fix = f: let result = f result; in result;
# Flip the order of the arguments of a binary function.
flip = f: a: b: f b a;
# `seq x y' evaluates x, then returns y. That is, it forces strict
# evaluation of its first argument.
seq = x: y: if x == null then y else y;
}