Node name changes (Rebased #85) (#97)

* Node name changes

* added clarification about case sensitivity

* fix idiocy

* minor

* update copyright

* Update docs/protocol/core/v3.0.rst

Co-authored-by: Alistair Miles <[email protected]>

Author: Carreau

docs/protocol/core/v3.0.rst

@@ -3,9 +3,9 @@
 ==================================
  Zarr core protocol (version 3.0)
 ==================================
----------------------------------
- Editor's draft 18 September 2020
----------------------------------
+-----------------------------
+ Editor's draft 16 October 2020
+-----------------------------
 
 Specification URI:
     https://purl.org/zarr/spec/protocol/core/3.0
@@ -16,7 +16,7 @@ Issue tracking:
 Suggest an edit for this spec:
     `GitHub editor <https://github.com/zarr-developers/zarr-specs/blob/core-protocol-v3.0-dev/docs/protocol/core/v3.0.rst>`_
 
-Copyright 2019, 2020 `Zarr core development
+Copyright 2019-Present `Zarr core development
 team <https://github.com/orgs/zarr-developers/teams/core-devs>`_ (@@TODO
 list institutions?). This work is licensed under a `Creative Commons
 Attribution 3.0 Unported
@@ -319,12 +319,16 @@ node names:
 
 * must be at most 255 characters long
 
-Note that node names are used to form storage keys, and that some
-storage systems will perform a case-insensitive comparison of storage
-keys during retrieval. Therefore, within a hierarchy, all nodes within
-a set of sibling nodes must have a name that is unique under
-case-insensitive comparison. E.g., the names "foo" and "FOO" are not
-allowed for sibling nodes.
+Node names are case sensitive, e.g., the names "foo" and "FOO" are **not**
+identical.
+
+.. note: 
+    The Zarr core development team recognises that restricting the set 
+    of allowed characters creates an impediment and bias against users
+    of different languages. We are actively discussing whether the full
+    Unicode character set could be allowed and what technical issues 
+    this would entail. If you have experience or views please comment on
+    `issue #56 <https://github.com/zarr-developers/zarr-specs/issues/56>`_.
 
 
 Data types
@@ -1055,7 +1059,8 @@ string containing only characters in the ranges ``a-z``, ``A-Z``,
 ``0-9``, or in the set ``/.-_``, and a `value` is any sequence of
 bytes. It is assumed that the store holds (`key`, `value`) pairs, with
 only one such pair for any given `key`. I.e., a store is a mapping
-from keys to values.
+from keys to values. It is also assumed that keys are case sensitive, 
+i.e., the keys "foo" and "FOO" are different.
 
 A store can make the following assumption on the structures of the keys it will receive:
 
@@ -1194,6 +1199,11 @@ which do not contain the character "/" after the given prefix.
     ``/``, ``.json``, ``.array``, ``.group``, they will otherwise be chunks
     data.
 
+Note that because keys are case sensitive, it is assumed that the operations 
+``set("foo", a)`` and ``set("FOO", b)`` will result in two separate (key, value) 
+pairs being stored. Subsequently ``get("foo")`` will return *a* and ``get("FOO")`` 
+will return *b*. 
+
 
 Store implementations
 ---------------------