groue

#import "GRMustache.h"

NSString *templateString = @"{{# repeat(Red) }}<img src=\"img/red.png\">{{/ repeat(Red) }}}";
GRMustacheTemplate *template = [GRMustacheTemplate templateFromString:templateString error:NULL];

id obj = @{
           @"Red": @10,
           @"repeat": [GRMustacheFilter filterWithBlock:^id(NSNumber *number) {
               NSInteger count = [number integerValue];
               return [GRMustache renderingObjectWithBlock:^NSString *(GRMustacheTag *tag, GRMustacheContext *context, BOOL *HTMLSafe, NSError *__autoreleasing *error) {

groue

import Foundation

// =============================================================================
// Box

// The Box
struct Box {
    let value: Any
    let walk: () -> ()
}

groue

import Mustache

// Wrap the result in a section, and the key `cycleKey` will enumerate and cycle
// around boxes, one after the other.
func cyclingBox(key cycleKey: String, #boxes: [MustacheBox]) -> MustacheBox {
    var index = 0
    return Box { (key: String) in
        if key == cycleKey {
            let box = boxes[index]
            index = (index + 1) % boxes.count

groue

import Foundation

// A function declared as rethrows that synchronously executes a throwing
// block in a dispatch_queue.
//
// Based on Ransak's answer to https://forums.developer.apple.com/message/19685
func perform_sync(queue: dispatch_queue_t, block: () throws -> Void) rethrows {
    func impl(queue: dispatch_queue_t, block: () throws -> Void, block2:((ErrorType) throws -> ()) ) rethrows {
        var blockError: ErrorType? = nil
        dispatch_sync(queue) {

groue

This blog post shows how Swift protocols can help using CoreData: http://martiancraft.com/blog/2015/07/objective-c-swift-core-data/

Following this advice, I have tried this technique, with success, but with a request for improvement.

Below you will find a bare minimal view of the API I'm working on. Notice the not nice Person.self in the line db.fetchAll(Person.self, "SELECT * FROM persons"). I want to improve that, and the linked blog post was a great deal of inspiration.

// Library
class RowModel {} // Equivalent of NSManagedObject in Core Data
class Database {

groue

// Library code
class Model { }
protocol Fetchable {
    typealias FetchableType
    static func fetchAll(sql: String) -> [FetchableType]
}

extension Fetchable where Self : Model, FetchableType == Self {
    static func fetchAll(sql: String) -> [FetchableType] {
        return []   // bare minimal, for demonstration purpose

groue

// Library code
class Model { }
protocol Fetchable {
    typealias FetchableType = Self
    static func fetchAll(sql: String) -> [FetchableType]
}

extension Fetchable where Self : Model, FetchableType == Self {
    static func fetchAll(sql: String) -> [FetchableType] {
        return []   // bare minimal, for demonstration purpose

groue

// Library code
class Model { }
protocol Fetchable {
    typealias FetchableType = Self
    static func fetchAll(sql: String) -> [FetchableType]
}

extension Fetchable where Self : Model, FetchableType == Self {
    static func fetchAll(sql: String) -> [FetchableType] {
        return []   // bare minimal, for demonstration purpose

groue

/// Given two sorted sequences (left and right), this function emits "merge steps"
/// which tell whether elements are only found on the left, on the right, or on
/// both sides.
///
/// Both sequences do not have to share the same element type. Yet elements must
/// share a common comparable *key*.
///
/// Both sequences must be sorted by this key.
///
/// Keys must be unique in both sequences.

groue

// 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
import GRDB