Although such a tool might allow piecemeal validation, it would not need to be used for validation but would simply provide JSON Schema type information corresponding to any point in a JSON data file (and possibly vice versa as well).
My interest in this would be as the core for the following uses for arbitrary JSON paired to a JSON schema file:
- a default display of a JSON file similar to JHTML, but JSON Schema-aware (e.g., displaying not only arrays as lists, strings within a bordered area, etc., but also URLs as links, HTML within an iframe preview, etc.)
- type-aware editing of a JSON file (similar to JSONEditor) or a subset/joins of JSON files
- type-aware (and hierarchy-aware) default search options for arbitrary JSON (e.g., exposing a date range UI when detecting date types--for refining one's search to branches of a data file which included date types of a certain range)
- enhancing JSONPath to be schema-aware (e.g., allowing for a single path expression to find all URL instances in a file)