JSON.NodeRule.Array.swift

internal import Grammar

extension JSON.NodeRule {
    /// Matches an array literal.
    ///
    /// Array literals begin and end with square brackets (`[` and `]`), and
    /// recursively contain instances of ``JSON.NodeRule`` separated by ``JSON.CommaRule``s.
    /// Trailing commas (a JSON5 extension) are not allowed.
    enum Array {
    }
}
extension JSON.NodeRule.Array: ParsingRule {
    typealias Terminal = UInt8

    static func parse<Source>(
        _ input: inout ParsingInput<some ParsingDiagnostics<Source>>
    ) throws -> [JSON.Node]
        where   Source.Element == Terminal,
        Source.Index == Location {
        try input.parse(as: JSON.BracketLeftRule<Location>.self)
        var elements: [JSON.Node]
        if let head: JSON.Node = try? input.parse(as: JSON.NodeRule<Location>.self) {
            elements = [head]
            while   let (_, next): (Void, JSON.Node) = try? input.parse(
                    as: (JSON.CommaRule<Location>, JSON.NodeRule<Location>).self
                ) {
                elements.append(next)
            }
        } else {
            elements = []
        }
        try input.parse(as: JSON.BracketRightRule<Location>.self)
        return elements
    }
}