CSD02 - simplify "schema" specification

When specifying the type for entries in lists or maps, one has 2 options:

1. Specify the name of an existing type
2. Define the schema for a new (anonymous) type in-line.

I propose that for the first option, we use a "shorthand" notation as follows:

tosca.properties.PortSpec:
properties:
target:
type: list
entry_schema: PortDef

For the second option (where a new anonymous type is defined in-line) I propose we use a simplified schema specification as follows:

tosca.properties.PortSpec:
properties:
target:
type: list
entry_schema:
derived_from: integer
constraints:

• in_range: [ 1, 65535 ]

The only key names that should be supported for schema specifcations are "derived_from", "constraints", and "properties". Neither case requires a "type" keyword (if an existing type is specified we use the shorthand notation) and neither case requires a "name" keyword (since type names are assigned externally in the "datatype_definition")

By the way, if we decide to adopt this proposal then I would also propose to rename entry_schema to entry_type

This issue was primarily intended to highlight modeling concerns, which were substantially addressed in the TOSCA Simple Profile for YAML TC discussion on 5 Mar 2015. The TC agrees, as per the reporter's suggestion, that the isssue be closed (see motion in minutes) and that, if needed, updated JIRA issues specific to the latest version of the spec be created.