JSON Schema - metadata could extend ReadiumWebPubManifest metadata schema?

[danielweck]

If the title / subtitle situation is harmonized ( see #24 ) would it be possible to use a JSON Schema "extension" mechanism so that OPDS metadat can inherit the dictionary fields already defined in the ReadiumWebPubManifest JSON Schema? The OPDS schema would then only need to specify itemsPerPage currentPage and numberOfItems, thereby avoiding redundant / duplicate definitions.

This:

drafts/schema/feed-metadata.schema.json

Lines 36 to 47 in 4d82fb9

	"itemsPerPage": {
	"type": "integer",
	"exclusiveMinimum": 0
	},
	"currentPage": {
	"type": "integer",
	"exclusiveMinimum": 0
	},
	"numberOfItems": {
	"type": "integer",
	"minimum": 0
	}

...would extend that:

https://github.com/readium/webpub-manifest/blob/0976680e25852b8a4c4802a052ba750ab3e89284/schema/metadata.schema.json

[danielweck]

Similar issue: #20

[HadrienGardeur]

I don't think that's a good idea for a feed's metadata since they're quite different potentially from a publication's metadata.

Purely from a JSON Schema perspective, how would "extending" work anyway?