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// To run this playground, select and build the GRDBOSX scheme.
//
// This sample code shows how to use GRDB to synchronize a database table
// with a JSON payload. We use as few SQL queries as possible:
//
// - Only one SELECT query.
// - One query per insert, delete, and update.
// - Useless UPDATE statements are avoided.

import Foundation

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@import UIKit;

@interface UIButton(Magic)
- (void)onTouchUpInside:(void(^)(UIButton *button))block NS_SWIFT_NAME(onTouchUpInside(_:));
@end

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// A replication of the convenience fetching methods of FetchableRecord,
// built for another record protocol: ContextFetchableRecord

protocol ContextFetchableRecord {
    associatedtype Context
    init(row: Row, context: Context)
}

extension ContextFetchableRecord {
    

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//: # Toward Enum Key Paths: a Protocol Hierarchy for Read-Only Key Paths
//:
//: This playground is an experiment for a protocol hierarchy of read-only
//: key paths that can handle both throwing and non-throwing getters.
//:
//: Since the Swift language has no support for throwing subscripts, we'll
//: perform our experiments with a very simplified setup that involves a single
//: getter function.
//:
//: ## The Protocol Hierarchy

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import Combine

/// A publisher that delivers values to its downstream subscriber on a
/// specific scheduler.
///
/// Unlike Combine's Publishers.ReceiveOn, ReceiveValuesOn only re-schedule
/// values and completion. It does not re-schedule subscription.
struct ReceiveValuesOn<Upstream: Publisher, Context: Scheduler>: Publisher {
    typealias Output = Upstream.Output
    typealias Failure = Upstream.Failure

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import Combine
import Foundation

/// A thread-safe store for cancellables which addresses usability pain points
/// with stock Combine apis.
///
/// ## Thread-safe storage of cancellables
///
///     let cancelBag = CancelBag()
///     cancellable.store(in: cancelBag)

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import Foundation

/// To create an operation:
///
/// 1. Subclass AsynchronousOperation, override main, and eventually cancel the
///    operation, or set result to a non-nil value.
///
/// 2. Use makeOperation { op in ... }, and eventually cancel the
///    operation, or set result to a non-nil value.
open class AsynchronousOperation<Output, Failure: Error>: Operation {

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import GRDB

extension QueryInterfaceRequest where RowDecoder: MutablePersistableRecord {
    /// Deletes all records in the database, but the ones selected by the request.
    ///
    /// For example:
    ///
    ///     // Delete all players whose score is below 1000
    ///     let bestPlayers = Player.filter(Column("score") > 1000)
    ///     try dbQueue.write(bestPlayers.deleteAllOther)

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import Combine

extension Publisher where Failure == Never {
    /// Same as assign(to:on:), but root object is not retained.
    func assignWeakly<Root: AnyObject>(
        to keyPath: ReferenceWritableKeyPath<Root, Self.Output>,
        on object: Root)
        -> AnyCancellable
    {
        var cancellable: AnyCancellable?

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extension Collection {
    /// Returns an array of subsequences of maximum size `chunkSize`.
    ///
    /// For example:
    ///
    ///     // ["ABCD", "EFGH", "IJ"]
    ///     "ABCDEFGHIJ".split(chunkSize: 4)
    ///
    /// - parameter chunkSize: the maximum size of the returned subsequences.
    /// - precondition: chunkSize > 0