Milan Schema Convertor To SharedTree LLS

[milanro]

Description

This is the initial implementation of the schema converter from Property DDS schema to SharedTree LLS schema.
It is based on the code at
https://github.com/sharptrip/FluidFramework/blob/editable-tree-inspector-with-transaction-handling/experimental/PropertyDDS/examples/schemas/src/schemaConverter.ts

Following are the changes and additions to the original code

Fields are never merged

Two fields of the Array context are not merged to one Empty Key field with both type1 and type2 instances possible. All fields are generated in the LLS schema as they were present in PDDS schema

        "filed1": {"kind": "Value", "types": ["array<Type1-1.0.0>"]},
        "field2": {"kind": "Value", "types": ["array<Type2-1.0.0>"]},

Enums

Enums are supported and converted to the type Enum which is the node containing the number value as follows

    "Enum": {
      "localFields": {},
      "globalFields": [],
      "extraLocalFields": {"kind": "Forbidden", "types": []},
      "extraGlobalFields": false,
      "value": 1
    }

OO Inheritance

Inheritance within the class hierarchy is covered by union of types. For example, if we have the types Ext2-1.0.0 inherits from Ext1-1.0.0 inherits from Base-1.0.0 and the Base is configured for the property fieldWithInherits, we get following schema structure

        "fieldWithInherits": {
          "kind": "Value",
          "types": [
            "Base-1.0.0",
            "Ext1-1.0.0",
            "Ext2-1.0.0"
          ]
        }

Review Notes

Reviewers:
@dstanesc @sharptrip @ruiterr