doc/tutorial/basics: doc fixes
Change-Id: I882e51fce43f91e4b7546800c84d1b13352de8d1
diff --git a/doc/tutorial/basics/defaults.md b/doc/tutorial/basics/defaults.md
index c65cb67..6af3c67 100644
--- a/doc/tutorial/basics/defaults.md
+++ b/doc/tutorial/basics/defaults.md
@@ -4,18 +4,16 @@
# Default Values
-If at the time of evaluation a sum type still has more than one possible
-value, the first error-free value is taken.
-A value is error free if it is not an error, it is a list with only error-free
-elements, or it is a struct where all field values are error-free.
-The default value must also not be ambiguous.
+Elements of a disjunction may be marked as preferred.
+If there is only one mark, or the users constraints a field enough such that
+only one mark remains, that value is the default value.
In the example, `replicas` defaults to `1`.
In the case of `protocol`, however, there are multiple definitions with
different, mutually incompatible defaults.
-It is still possible to resolve this error by explicitly setting the value
-for protocol.
-Try it!
+In that case, both `"tcp"` and `"udp"` are preferred and one must explicitly
+specify either `"tcp"` or `"udp"` as if no marks were given.
+
<!-- CUE editor -->
```
// any positive number, 1 is the default
