Experimental Auto Layout short syntax (visual format)

gistfile1.m

// Usage example : [self addConstraintsWithVisualFormat:@"V:|-0-[myAwesomeView]-0-|", self.awesome, nil];
// no need to use underscore for property
// Actually would break with priority annotations but who care! It's just an experiment
// Not using NSDictionaryOfVariableBindings(...) to have easy use also in swift

- (void)addConstraintsWithVisualFormat:(NSString *)formatString,... NS_REQUIRES_NIL_TERMINATION {
    va_list args;
    va_start(args, formatString);
    
    NSString *pattern = @"\\[(.*?)\\]";
    NSError *error = nil;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:0 error:&error];
    NSArray *matches = [regex matchesInString:formatString options:0 range:NSMakeRange(0, formatString.length)];

    NSAssert(!error, error.description);
    if (error || !matches) {
        return;
    }
    
    NSMutableDictionary *views = [NSMutableDictionary dictionary];
    NSInteger idx = 0;
    for (id arg = va_arg(args, id); arg != nil; arg = va_arg(args, id)) {
        NSString *key = [formatString substringWithRange:[(NSTextCheckingResult *)matches[idx] rangeAtIndex:1]];
        views[key] = arg;
        idx++;
    }
    
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:formatString options:nil metrics:nil views:views]];
    va_end(args);
}