Clean-up of Sequence

cloudevents/extensions/sequence.md

@@ -1,15 +1,18 @@
 # Sequence
 
-This extension defines two attributes that can be included within a CloudEvent
+This extension defines an attribute that can be included within a CloudEvent
 to describe the position of an event in the ordered sequence of events produced
 by a unique event source.
 
 The `sequence` attribute represents the value of this event's order in the
-stream of events. The exact value and meaning of this attribute is defined by
-the `sequencetype` attribute. If the `sequencetype` is missing, or not defined
-in this specification, event consumers will need to have some out-of-band
-communication with the event producer to understand how to interpret the value
-of the attribute.
+stream of events. This specification does not define the meaning or set of
+valid value of this attribute, rather it only mandates that the value be
+a string that can be lexicographically compared to other `sequence` values
+to determine which one comes first. The `sequence` with a lower lexicographical
+value comes first.
+
+Produces and consumers are free to define an out-of-band agreement on the
+semantic meaning, or valid values, for the attribute.
 
 ## Attributes
 
@@ -23,27 +26,9 @@ of the attribute.
   - MUST be a non-empty lexicographically-orderable string
   - RECOMMENDED as monotonically increasing and contiguous
 
-### sequencetype
-
-- Type: `String`
-- Description: Specifies the semantics of the sequence attribute. See the
-  [SequenceType Values](#sequencetype-values) section for more information.
-- Constraints:
-  - OPTIONAL
-  - If present, MUST be a non-empty string
-
-## SequenceType Values
-
-This specification defines the following values for `sequencetype`. Additional
-values MAY be defined by other specifications.
-
-### Integer
-
-If the `sequencetype` is set to `Integer`, the `sequence` attribute has the
-following semantics:
-
-- The values of `sequence` are string-encoded signed 32-bit Integers.
-- The sequence MUST start with a value of `1` and increase by `1` for each
-  subsequent value (i.e. be contiguous and monotonically increasing).
-- The sequence wraps around from 2,147,483,647 (2^31 -1) to -2,147,483,648
-  (-2^31).
+The entity creating the CloudEvent MUST ensure that the `sequence` values
+used are formatted such that across the entire set of values used a receiver
+can determine the order of the events via a simple string-compare type of
+operation. This means that it might be necessary for the value to include
+some kind of padding (e.g. leading zeros in the case of the value being the
+string representation of an integer).