json_schema_ast

Strict Draft 2020-12 JSON Schema documents, validation, and resolved schema IR.

Installation

Add to your Cargo.toml:

[dependencies]
json_schema_ast = "0.2.6"

Usage

use json_schema_ast::{SchemaDocument, compile};
use serde_json::json;

let raw = json!({
    "type": "object",
    "properties": {
        "id": { "type": "integer" },
        "name": { "type": "string" }
    },
    "required": ["id"]
});

// Build a document. Construction canonicalizes the schema and checks keyword shapes.
let schema = SchemaDocument::from_json(&raw).unwrap();

// Validate instances with the raw-schema validator backend.
assert!(schema.is_valid(&json!({ "id": 42 })).unwrap());
assert!(!schema.is_valid(&json!({ "name": "Ada" })).unwrap());

// Compile a validator directly if you need to own the backend type.
let validator = compile(&raw).unwrap();
assert!(validator.is_valid(&json!({ "id": 42 })));

Public Interface

For validation callers:

• SchemaDocument::from_json(&Value) builds a document from a raw Draft 2020-12 JSON Schema.
• SchemaDocument::is_valid(&Value) validates instances against the original raw schema.
• SchemaDocument::canonical_schema_json() exposes the canonicalized schema used for IR construction and debugging.
• compile(&Value) returns the underlying jsonschema::JSONSchema validator after this crate's dialect checks.
• AstError, SchemaBuildError, SchemaError, and CompileError are the typed error surfaces.

For resolved-IR consumers:

• SchemaDocument::root() returns the lazily resolved immutable SchemaNode graph.
• SchemaNode::kind() exposes the non-exhaustive SchemaNodeKind IR for downstream analyzers.
• SchemaNode::id() exposes opaque node identity for cycle guards.
• SchemaNode::accepts_value() is a low-level evaluator for resolved subgraphs; use SchemaDocument::is_valid() for user-visible validation.
• json_values_equal(&Value, &Value) compares JSON values using JSON Schema's numeric equality rule.

The supporting constraint types exposed through SchemaNodeKind are deliberately structured: IntegerBounds, NumberBounds, and CountRange reject empty intervals at construction; ContainsConstraint keeps the contains schema and match-count range together; and PatternConstraint records whether the internal Rust matcher can evaluate a JSON Schema pattern.

The resolved IR entrypoints are public because jsoncompat and json_schema_fuzz are separate crates; most users only need the validation API.

If a schema document sets $schema, it must be exactly Draft 2020-12 (https://json-schema.org/draft/2020-12/schema, with an optional trailing #). Omitting $schema is allowed and is interpreted as Draft 2020-12.

Same-document refs to "#" and "#/..." are supported, including recursive graphs. Pure alias cycles, remote refs, plain-name fragments, and dynamic refs are rejected with typed resolver errors.

License

Licensed under MIT. See LICENSE.