summaryrefslogtreecommitdiffhomepage
diff options
context:
space:
mode:
-rw-r--r--nix.html.markdown6
1 files changed, 6 insertions, 0 deletions
diff --git a/nix.html.markdown b/nix.html.markdown
index ef59a135..ba122a46 100644
--- a/nix.html.markdown
+++ b/nix.html.markdown
@@ -208,6 +208,12 @@ with builtins; [
{ a = 1; b = 2; }.a
#=> 1
+ # The ? operator tests whether a key is present in a set.
+ ({ a = 1; b = 2; } ? a)
+ #=> true
+ ({ a = 1; b = 2; } ? c)
+ #=> false
+
# The // operator merges two sets.
({ a = 1; } // { b = 2; })
#=> { a = 1; b = 2; }