[mhalle]

XML would require a schema to express the concepts in Preserves, or JSON for that matter.

The reason JSON is lower friction than XML for data representation is that you get basic data representations (numbers, strings, arrays, maps) for free in a natural native syntax that happens to parallel multiple programming languages.

XML, in contrast, is a meta-language that allows schema to express different data representations. You've got to use attributes and elements to represent data and data types. XSD is a common datatype schema, but it's quite verbose, and data serialization looks very different from what it looks like in a programming language representation.

Preserves looks like a superset of JSON. It includes additional data representation concepts through syntax extensions, but the idea is the same.

What I don't see is a standard way to map record types (like "irl" in the tutorial) to a unique identifier like an URI/IRI, or something like a CURIE. That kind of feature would allow Preserves to better describe standardized record types.