Tweaks

preserves-schema.md

@@ -179,7 +179,7 @@ are *merged* together.
 #### Experimental.
 
 Intersections are an experimental feature. They can be used to express
-*optional dictionary entries*:
+*optional dictionary entries*:[^not-ideal-optional-encoding]
 
     MyDict = {a: int, b: string} & @c MaybeC .
     MaybeC = @present {c: symbol} / @absent {} .
@@ -188,6 +188,11 @@ It is not yet clear whether they pull their weight. In particular, the
 semantics of serializing a value defined by intersection are not
 completely clear.
 
+[^not-ideal-optional-encoding]: This encoding is not ideal. Given a
+    term `{a: 1, b: "", c: sym}`, it will yield a `present` result,
+    and given `{a: 1, b: ""}`, will yield an `absent` result; but
+    `absent` will also result from `{a: 1, b: "", c: "notasymbol"}`.
+
 ### Patterns.
 
     Pattern = SimplePattern / CompoundPattern
@@ -262,8 +267,8 @@ A record pattern matches an input record. It may be specified as a
 record with a literal in the label position, or as a quoted `<<rec>
 ... >` record:
 
-    RecordPattern = "<" value *(NamedPattern) ">"
-                  / "<<rec>" NamedPattern *(NamedPattern) ">"
+    RecordPattern = "<<rec>" NamedPattern *(NamedPattern) ">"
+                  / "<" value *(NamedPattern) ">"
 
 A tuple pattern matches a fixed-length sequence with specific patterns
 in each position. A variable tuple pattern is the same, but with an