チューリングマシンで１を足すというのはこんな感じで動くのでは、、というiPhoneアプリのサンプルコードを描いてみます。
#import “ViewController.h”
@interface ViewController ()
@property (nonatomic, strong) NSMutableArray *tape;
@property (nonatomic, weak) UIView *anchor;
@property (nonatomic) int index;
@property (nonatomic, strong) SEL (^condition)();
@end
@implementation ViewController
– (void)viewDidLoad
{
[super viewDidLoad];
self.view.backgroundColor = [UIColor colorWithRed:0.5 green:0.5 blue:0 alpha:1];
self.index = 2;
id __weak weakSelf = self;
self.condition = ^SEL{ return [weakSelf conditionA]; };
[self createInitialTape];
[self updateAnchor];
[self createStartButton];
}
– (void)createInitialTape
{
NSString* (^randOneToNine)() = ^NSString* {
return [@(arc4random() % 9 + 1) stringValue];
};
// random number 111 ~ 999
NSArray *digit = @[randOneToNine(),randOneToNine(),randOneToNine()];
for (int i=0; i<5; i++) {
UITextField *t = [[UITextField alloc] initWithFrame:CGRectMake(i*50+35, 150, 50, 50)];
t.tag = i + 1;
t.font = [UIFont boldSystemFontOfSize:50];
t.textAlignment = NSTextAlignmentCenter;
t.textColor = [UIColor lightGrayColor];
t.backgroundColor = [UIColor blackColor];
t.layer.borderWidth = 5;
t.layer.borderColor = [UIColor darkGrayColor].CGColor;
if (i > 0 && i< 4) {
t.text = digit[i – 1];
}
[self.view addSubview:t];
}
}
– (void)updateAnchor
{
UIView *t = [self.view viewWithTag:self.index];
if (!self.anchor) {
UILabel *anchor = [[UILabel alloc] init];
anchor.font = [UIFont boldSystemFontOfSize:50];
anchor.text = @”▲”;
[anchor sizeToFit];
self.anchor = anchor;
[self.view addSubview:anchor];
}
dispatch_async(dispatch_get_main_queue(), ^{
self.anchor.center = CGPointMake(t.center.x, t.center.y + 50);
});
}
– (void)createStartButton
{
UIButton *start = [UIButton buttonWithType:UIButtonTypeSystem];
start.titleLabel.font = [UIFont systemFontOfSize:30];
[start setTitle:@”step” forState:UIControlStateNormal];
[start sizeToFit];
start.center = CGPointMake(160, 350);
[self.view addSubview:start];
[start addTarget:self action:@selector(step) forControlEvents:UIControlEventTouchUpInside];
}
– (void)step
{
SEL f = self.condition();
if ([self respondsToSelector:f]) {
[self performSelector:f withObject:nil afterDelay:0.0];
}
}
#pragma mark – A
– (SEL)conditionA
{
UITextField *t = (UITextField *)[self.view viewWithTag:self.index];
if (t.text.length == 0) {
return @selector(functionA0);
}
return @selector(functionA1);
}
– (void)functionA0
{
self.index–;
[self updateAnchor];
id __weak weakSelf = self;
self.condition = ^SEL{ return [weakSelf conditionB]; };
}
– (void)functionA1
{
self.index++;
[self updateAnchor];
}
#pragma mark – B
– (SEL)conditionB
{
UITextField *t = (UITextField *)[self.view viewWithTag:self.index];
if (t.text.length == 0) {
return @selector(functionB0);
} else if ([t.text isEqual:@”9″]) {
return @selector(functionB1);
}
return @selector(functionB2);
}
– (void)functionB0
{
UITextField *t = (UITextField *)[self.view viewWithTag:self.index];
t.text = @”1″;
// finish
}
– (void)functionB1
{
UITextField *t = (UITextField *)[self.view viewWithTag:self.index];
t.text = @”0″;
self.index–;
[self updateAnchor];
}
– (void)functionB2
{
UITextField *t = (UITextField *)[self.view viewWithTag:self.index];
t.text = [NSString stringWithFormat:@”%d”, [t.text intValue] + 1];
self.index–;
[self updateAnchor];
id __weak weakSelf = self;
self.condition = ^SEL{ return [weakSelf conditionC]; };
}
#pragma mark – C
– (SEL)conditionC
{
UITextField *t = (UITextField *)[self.view viewWithTag:self.index];
if (t.text.length == 0) {
return @selector(functionC0);
}
return @selector(functionC1);
}
– (void)functionC0
{
self.index++;
[self updateAnchor];
id __weak weakSelf = self;
self.condition = ^SEL{ return [weakSelf conditionA]; };
}
– (void)functionC1
{
self.index–;
[self updateAnchor];
}
@end