jsonette-core 0.4.0

JSON parse, format, query, and diagnostics engine — core library for the jsonette tool
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/*
 * Copyright (c) 2026 DevEtte.
 *
 * This project is dual-licensed under both the MIT License and the
 * Apache License, Version 2.0 (the "License"). You may not use this
 * file except in compliance with one of these licenses.
 *
 * You may obtain a copy of the Licenses at:
 * - MIT: https://opensource.org
 * - Apache 2.0: http://apache.org
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//! The parsing module contains the strict and tolerant JSON parsers,
//! as well as fast diagnostics syntax checking and parsing helper utilities.

pub mod strict;
pub mod tolerant;
pub mod utils;

pub use strict::parse;

use crate::json_node::JsonNode;
use crate::types::Diagnostic;

/// Tolerant parsing: Attempts to build a partial AST even if errors are present.
/// Useful for live IDE feedback while typing, preserving as much of the tree as possible.
///
/// # Arguments
///
/// * `input` - The raw JSON string slice to parse (potentially incomplete or invalid).
///
/// # Returns
///
/// A tuple containing:
/// * `Option<JsonNode>` - The partial AST tree if any structure could be recovered.
/// * `Vec<Diagnostic>` - A list of errors encountered during parsing.
pub fn tolerant_parse(input: &str) -> (Option<JsonNode>, Vec<Diagnostic>) {
    // We opted for a hand-rolled tolerant parser (Option B) instead of tree-sitter.
    // While tree-sitter provides excellent error recovery, it introduces a C dependency
    // which complicates the cross-platform UniFFI build (especially for iOS/Android targets),
    // and slightly increases binary size. A minimal hand-rolled parser is sufficient for
    // JSON and gives us full control over `JsonNode` span generation without an intermediate AST.
    tolerant::parse(input)
}

/// Fast validation path: parses and returns only syntax or structural errors
/// without fully allocating the resulting AST tree.
///
/// # Arguments
///
/// * `input` - The raw JSON string slice to validate.
///
/// # Returns
///
/// A list of `Diagnostic` errors found in the input. If the input is valid JSON, this is empty.
pub fn diagnostics(input: &str) -> Vec<Diagnostic> {
    // Fast validation path: for M0, we simply delegate to tolerant_parse
    // and return the extracted diagnostics. Future performance optimizations
    // can skip AST allocation entirely if necessary.
    tolerant_parse(input).1
}

#[cfg(test)]
mod stub_tests {
    use super::*;

    #[test]
    fn test_tolerant_parse_is_implemented() {
        let (node, _) = tolerant_parse("{}");
        assert!(node.is_some());
    }

    /// **Test Case**: Fast Validation Returns Proper Diagnostics
    ///
    /// ### Description
    /// Verifies that the fast `diagnostics` validation path correctly identifies
    /// valid and invalid JSON document syntax.
    ///
    /// ### Test Procedure
    /// 1. Call `diagnostics` on a valid JSON document `{}`.
    /// 2. Call `diagnostics` on an invalid JSON document `{`.
    ///
    /// ### Expected Result
    /// The valid document returns an empty `Vec<Diagnostic>`. The invalid document
    /// returns a non-empty `Vec<Diagnostic>`.
    #[test]
    fn test_diagnostics() {
        let diags = diagnostics("{}");
        assert!(diags.is_empty());

        let diags = diagnostics("{");
        assert!(!diags.is_empty());
    }
}