spec: document 3-arg getattr

Change-Id: I0d547e0cdc908b89250115805925f83fa2d87714

1 files changed, 3 insertions, 0 deletions

diff --git a/doc/spec.md b/doc/spec.md
index f496282..211650e 100644
--- a/doc/spec.md
+++ b/doc/spec.md
@@ -3007,6 +3007,9 @@ It is a dynamic error if x has no such attribute.
 getattr("banana", "split")("a")	       # ["b", "n", "n", ""], equivalent to "banana".split("a")
 ```
 
+The three-argument form `getattr(x, name, default)` returns the
+provided `default` value instead of failing.
+
 ### hasattr
 
 `hasattr(x, name)` reports whether x has an attribute (field or method) named `name`.