diff options
Diffstat (limited to 'lib/trivial.nix')
-rw-r--r-- | lib/trivial.nix | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/lib/trivial.nix b/lib/trivial.nix index c452c7b65bc..5f18c0b61cc 100644 --- a/lib/trivial.nix +++ b/lib/trivial.nix @@ -81,6 +81,31 @@ rec { */ mod = base: int: base - (int * (builtins.div base int)); + /* C-style comparisons + + a < b => -1 + a == b => 0 + a > b => 1 + */ + compare = a: b: + if a < b + then -1 + else if a > b + then 1 + else 0; + + /* Split type into two subtypes by predicate `p`, assume + + forall x y . x < y if p x == true && p y == false + + compare elements of the same subtype with `yes` and `no` + comparisons respectively. + */ + splitByAndCompare = p: yes: no: a: b: + if p a + then if p b then yes a b else -1 + else if p b then 1 else no a b; + /* Reads a JSON file. */ importJSON = path: builtins.fromJSON (builtins.readFile path); |