Software Design & Eclecticism

What makes Foundation stand out among other standard libraries is how thoroughly it's designed. From its date and time calculations to its internationalization and URL loading system, Cocoa APIs demonstrate thoughtfulness and a deep appreciation for understanding a problem in its entirety.

In the service of cultivating a sense and appreciation of good software design, this session will explore a variety of topics, including beer taxonomy, international shoe sizes, NFPA 704 "fire diamonds", and the French Republican Calendar, applying patterns and conventions in Objective-C and Cocoa to model these obscure subjects.

In the service of cultivating a sense and appreciation of good software design, this session will explore a variety of topics, including beer taxonomy, SMPTE film timecodes, international shoe sizes, NFPA 704 "fire diamonds", and the French Republican Calendar, applying patterns and conventions in Objective-C and Cocoa to model these obscure subjects.

Transcript

1. Software
   Design &
   Eclecticism
   

   View Slide

2. • UITableView Wrangler
   • URL Request Slinger
   • JSON Serialization Expert
   • Getter/Setter Go-Getter
   • Documentation Force of Nature
   • NSManagedObject Whisperer
   

   View Slide

3. This is a talk about getting back to what 

   I love most about programming
   

   View Slide

4. French Republican Calendar
   

   View Slide

5. 1793 – 1805
   

   View Slide

6. Design Goals
   

   View Slide

7. 12 Months of
   3 Weeks of
   10 Days of
   10 Hours of
   100 Minutes of
   100 Seconds
   

   View Slide

8. Vendémiaire Nivôse Germinal Messidor
   Brumaire Pluviôse Floréal Thermidor
   Frimaire Ventôse Prairial Fructidor
   -aire -ôse -al -dor
   

   View Slide

9. 1.primidi
   2.duodi
   3.tridi
   4.quartidi
   5.quintidi

   6.sextidi
   7.septidi
   8.octidi
   9.nonidi
   10.décadi
   

   View Slide

10. Brumaire 1
    Pomme
    Pluviôse 25
    Lièvre
    

    View Slide

11. 360 Days
    + 

    5 or 6 

    “Complementary Days”
    

    View Slide

12. Les Jours Complémentaires
    • Celebration of Virtue
    • Celebration of Talent
    • Celebration of Labor
    • Celebration of Convictions
    • Celebration of Honors
    • Celebration of the Revolution
    

    View Slide

13. NSCalendar
    

    View Slide

14. NSCalendar 

    -initWithCalendarIdentifier:
    

    View Slide

15. • Gregorian
    • Buddhist
    • Chinese
    • Hebrew
    • Islamic
    • Islamic Civil

    • Japanese
    • Republic of China
    • Persian
    • Indian
    • ISO 8601
    

    View Slide

16. _NSCopyOnWriteCalendarWrapper

    

    CFCalendarRef
    

    View Slide

17. @interface _FRARepublicanCalendar : 

    NSCalendar
    @end
    

    View Slide

18. NSString * const 

    NSCalendarIdentifierFrenchRepublican =

    @"calendrier-républicain-français"
    

    View Slide

19. - (id)fra_initWithCalendarIdentifier:(NSString *)ident 

    __attribute__((objc_method_family(init))) 

    {
    if ([ident isEqualToString:
    NSCalendarIdentifierFrenchRepublican]) {
    return [[_FRARepublicanCalendar alloc] init];
    }
    !
    return [self fra_initWithCalendarIdentifier:ident];
    }
    

    View Slide

20. - (NSRange)maximumRangeOfUnit:(NSCalendarUnit)unit {
    switch (unit) {
    case NSYearCalendarUnit:
    return NSMakeRange(-NSUIntegerMax, NSUIntegerMax);
    case NSMonthCalendarUnit: return NSMakeRange(1, 13);
    case NSWeekCalendarUnit: return NSMakeRange(1, 3);
    case NSWeekdayCalendarUnit: return NSMakeRange(1, 10);
    case NSDayCalendarUnit: return NSMakeRange(1, 30);
    case NSHourCalendarUnit: return NSMakeRange(1, 10);
    case NSMinuteCalendarUnit: return NSMakeRange(1, 100);
    case NSSecondCalendarUnit: return NSMakeRange(1, 100);
    case NSEraCalendarUnit:
    default: return NSMakeRange(0, 0);
    }
    }
    

    View Slide

21. NSTimeInterval const
    FRAFrenchRevolutionaryEpoch =
    2375839.5; // 22 September 1792
    

    View Slide

22. - components:

    fromDate:
    - dateByAddingComponents:

    toDate:
    - dateFromComponents:
    

    View Slide

23. Phone Numbers
    

    View Slide

24. +1 (555) 555 - 1234
    United States
    

    View Slide

25. +44 20 1234 5678
    United Kingdom
    

    View Slide

26. 1 2
    ABC
    3
    DEF
    4
    GHI
    5
    JKL
    6
    MNO
    7
    PQRS
    8
    TUV
    9
    WXYZ
    ˎ 0
    +
    #
    

    View Slide

27. Whitby 

    01947 (WH)
    

    View Slide

28. 1-800-HIPSTER
    Alphabetical Phone Number
    

    View Slide

29. +1 (555) 555 - 6789 x42
    Extension
    

    View Slide

30. 911
    Emergency Number
    

    View Slide

31. 55422
    SMS Short Code
    

    View Slide

32. IP Addresses
    

    View Slide

33. E.164
    Telephone Numbering Plan
    

    View Slide

34. International Access Code 011
    Country Code +44
    Area Code 555
    Subscriber Number 555 1234
    Extension x42
    

    View Slide

35. E164PhoneNumberComponents
    

    View Slide

36. • @property NSString *internationalAccessCode
    • @property NSString *countryCode
    • @property NSString *areaCode
    • @property NSString *subscriberNumber
    • @property NSString *extension
    • @property NSString *emergencyNumber
    • @property NSString *shortCode
    

    View Slide

37. E164PhoneNumberComponents
    

    View Slide

38. E164PhoneNumberFormatter
    • @property NSLocale *locale
    • @property NSString *countryCodePrefix
    • @property NSString *extensionPrefix
    

    View Slide

39. - phoneNumberWithComponents:
    - components:

    fromPhoneNumber:
    

    View Slide

40. NFPA 704 

    Hazard Identification System
    

    View Slide

41. 3
    2 0
    Ethyl Alcohol
    CH3CH2OH
    

    View Slide

42. 1
    0 2
    Sodium Hydride
    NaH
    W
    

    View Slide

43. 4
    3 2
    W
    

    View Slide

44. 4
    3 2
    W
    • @property flammabilityLabel
    • @property healthLabel
    • @property reactivityLabel
    • @property specialNoteLabel
    

    View Slide

45. 4
    3 2
    W
    • @property flammabilityBackgroundColor
    • @property healthBackgroundColor
    • @property reactivityBackgroundColor
    • @property specialNoteBackgroundColor
    

    View Slide

46. typedef NS_ENUM(NSUInteger, NFPA704HazardLevel) {
    NFPA704MinimalHazard = 0,
    NFPA704SlightHazard = 1,
    NFPA704ModerateHazard = 2,
    NFPA704SeriousHazard = 3,
    NFPA704ExtremeHazard = 4,
    };
    • @property NFPA704HazardLevel flammability
    • @property NFPA704HazardLevel health
    • @property NFPA704HazardLevel reactivity
    • @property NSString *specialNote
    

    View Slide

47. CGContextSaveGState(ctx);
    {
    CGContextTranslateCTM(ctx,CGRectGetWidth(rect)/2.0f, 0.0f);
    CGContextRotateCTM(ctx, M_PI_4);
    CGContextScaleCTM(ctx, 1.0f / M_SQRT2, 1.0f / M_SQRT2);
    // …
    }
    CGContextRestoreGState(ctx);
    

    View Slide

48. Beer Measurement
    

    View Slide

49. @interface Beer
    @property NSString *name
    @property id brewery
    @property NSNumber *ABV
    @property NSNumber *IBU
    @property NSNumber *SRM
    

    View Slide

50. °L Example Color EBC
    2 Pale lager, Witbier, Pilsener, Berliner Weisse 4
    3 Maibock, Blonde Ale 6
    4 Weissbier 8
    6 American Pale Ale, India Pale Ale 12
    8 Weissbier, Saison 16
    10 English Bitter, ESB 20
    13 Biere de Garde, Double IPA 26
    17 Dark lager, Vienna lager, Marzen, Amber Ale 33
    20 Brown Ale, Bock, Dunkel, Dunkelweizen 39
    24 Irish Dry Stout, Doppelbock, Porter 47
    29 Stout 57
    35 Foreign Stout, Baltic Porter 69
    40+ Imperial Stout 79
    

    View Slide

51. Morey Equation
    MCU =
    weight of grains (lbs) • color of grains (°L)
    volume (gallons)
    SRM = 1.4922 • MCU^0.6859
    

    View Slide

52. Morey Approximation
    UIColor * UIColorForDegreesLovibond(CGFloat lovibond) {
    CGFloat r, g, b;
    if (lovibond < 1.7f) {
    r = 226.6017f, g = 174.7456f, b = 101.7924;
    } else if (lovibond > 600.0f) {
    r = 76.52f, g = 58.344f, b = 47.936f;
    } else {
    r = (227.3 - 0.4112 * lovibond) + (0.0002665 * powf(lovibond, 2.0f));
    g = (175.5 - 0.4445 * lovibond) + (0.0004154 * powf(lovibond, 2.0f));
    b = (102.2 - 0.2402 * lovibond) + (0.0002496 * powf(lovibond, 2.0f));
    }
    !
    return [UIColor colorWithRed:(r / 255.0f)
    green:(g / 255.0f)
    blue:(b / 255.0f) alpha:1.0f];
    }
    

    View Slide

53. @interface BeerView
    - setBeer:
    

    View Slide

54. Shoe Sizing
    

    View Slide

55. UK Barleycorn ⅓ inch
    France Paris Point ⅔ cm
    

    View Slide

56. • Europe
    • UK
    • Australia
    • USA / Canada
    • Mexico
    • Japan
    • Korea

    • Inches
    • Centimeters
    Regional Systems Measurements
    

    View Slide

57. ISO 9407
    Mondopoint
    

    View Slide

58. 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 285 290 295 300 305 310 315 320
    7¾ 8 8¼ 8½ 8¾ 9 9¼ 9½ 9¾ 10 10¼ 10½ 10¾ 11 11¼ 11½ 11¾ 12 12¼ 12½
    [mm]
    [in]
    foot
    215 220 225 230 235 240 245 250 255 260 265 270 275 280 285 290 295 300 305 310 315 320 325 330 335
    8¼ 8½ 8¾ 9 9¼ 9½ 9¾ 10 10¼ 10½ 10¾ 11 11¼ 11½ 11¾ 12 12¼ 12½ 12¾ 13
    [mm]
    [in]
    shoe
    Mondopoint 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 285 290 295 300 305 310 315 320
    EUR 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
    UK 0 0½ 1 1½ 2 2½ 3 3½ 4 4½ 5 5½ 6 6½ 7 7½ 8 8½ 9 9½ 10 10½ 11 11½ 12 12½ 13 13½ 14
    64ø. 1 1½ 2 2½ 3 3½ 4 4½ 5 5½ 6 6½ 7 7½ 8 8½ 9 9½ 10 10½ 11 11½ 12 12½ 13 13½ 14 14½ 15
    64ø.ø "UIM
    2 2½ 3 3½ 4 4½ 5 5½ 6 6½ 7 7½ 8 8½ 9 9½ 10 10½ 11 11½ 12 12½ 13 13½ 14
    64ø8ø '*"
    2 2½ 3 3½ 4 4½ 5 5½ 6 6½ 7 7½ 8 8½ 9 9½ 10 10½ 11 11½ 12 12½ 13 13½ 14 14½ 15 15½ 16
    64ø8ø "UIM
    3 3½ 4 4½ 5 5½ 6 6½ 7 7½ 8 8½ 9 9½ 10 10½ 11 11½ 12 12½ 13 13½ 14 14½ 15
    JP/CN 20 20½ 21 21½ 22 22½ 23 23½ 24 24½ 25 25½ 26 26½ 27 27½ 28 28½ 29 29½ 30
    

    View Slide

59. Function or Lookup Table?
    

    View Slide

60. #import
    !
    extern double USAWomensSizeToMondopoint(double size);
    !
    - (void)testUSAWomensSizeToMondopointEquivalences {
    static NSDictionary *mondopointByWomensSize =
    @{@(2): @(203), ...};
    !
    [mondopointByWomensSize enumerateKeysAndObjectsUsingBlock:
    ^(NSNumber *womensSize, NSNumber *mondopoint, BOOL *stop) {
    XCTAssertEqual(
    USAWomensSizeToMondopoint([womensSize doubleValue]),
    [mondopoint doubleValue],
    @"sizes not equivalent”
    );
    }];
    }
    

    View Slide

61. Braille
    

    View Slide

62. a/1 b/2 c/3 d/4 e/5 f/6 g/7 h/8 i/9 j/0
    k l m n o p q r s t
    u v x y z w
    

    View Slide

63. Comma Semicolon Apostrophe Colon Hyphen Decimal point
    Full stop!
    (Period)
    Exclamation!
    point
    Open quote,!
    question mark
    Close!
    quote
    Bracket!
    (Parentheses)
    Slash!
    (Fraction)
    

    View Slide

64. UISimpleTextPrintFormatter
    

    View Slide

65. NSMutableString *mutableText = [text mutableCopy];
    !
    CFStringTransform(mutableText, NULL,
    kCFStringTransformToLatin, NO);
    !
    CFStringTransform(mutableText, NULL,
    kCFStringTransformStripCombiningMarks, NO);
    !
    text = [NSString stringWithString:mutableText];
    

    View Slide

66. NSMutableString *mutableBrailleText = [NSMutableString string];
    [text enumerateSubstringsInRange:NSMakeRange(0, [text length])
    options:NSStringEnumerationByComposedCharacterSequences
    usingBlock:
    ^(NSString *substring, …) {
    [mutableBrailleText appendString:
    EnglishBrailleCharacterForCharacter([substring characterAtIndex:0])];
    }];
    !
    [super setText:mutableBrailleText];
    

    View Slide

67. static NSString * EnglishBrailleCharacterForCharacter(unichar character) {
    switch (character) {
    case 'a':
    return @"⠁";
    case 'b':
    return @"⠃";
    // ...
    }
    !
    return nil;
    }
    

    View Slide

68. Concepts
    • Swizzling & Private Class Clusters
    • Formatters vs. Value Transformers vs. Functions
    • View Composition & Transformations
    • Model-Driven Views
    • Unit Conversion Strategies & Unit Testing
    • String Enumeration & UIPrinterFormatter
    

    View Slide