lib.guard: init

2016-06-13 01:12:10 +02:00 · 2016-06-13 01:12:10 +02:00 · 3c61d227cf
commit 3c61d227cf
parent ac3b87b9a6
1 changed files with 10 additions and 0 deletions
--- a/krebs/4lib/default.nix
+++ b/krebs/4lib/default.nix
@ -15,6 +15,16 @@ let out = rec {

  addNames = mapAttrs addName;

+  guard = spec@{ type, value, ... }:
+    assert isOptionType type;
+    if type.check value
+      then value
+      else throw (toString (filter isString [
+        "argument"
+        (if spec ? name then "‘${spec.name}’" else null)
+        "is not a ${type.name}"
+      ]));
+
  types = import ./types.nix {
    inherit config;
    lib = lib // { inherit genid optionalTrace; };