Example for storing Calabash Backdoor functions outside of the Application Delegate

CalabashBackdoor.h

@interface CalabashBackdoor : NSObject

+(NSString *) backdoorMethodName:(NSString *)string;

@end

CalabashBackdoor.m

@implementation CalabashBackdoor

// One of the Backdoor methods
+ (NSString *) backdoorMethodName:(NSString *)string
{
    return @"Result";
}

@end

ruby_helper_file.rb

backdoor('calabashBackdoor','backdoorMethodName')
backdoor('calabashBackdoor','backdoorMethodName:')
backdoor('calabashBackdoor','backdoorMethodName:parameterValue')

YourApplicationDelegate.h

// Calabash Automation Methods Proxy
-(id *)calabashBackdoor:(NSString *)string;

YourApplicationDelegate.m

// Calls the corresponding method inside the CalabashBackdoor
// Syntax from Ruby Code:
//   backdoor('calabashBackdoor','functionName:parameter')
//   backdoor('calabashBackdoor','functionName')
//   backdoor('calabashBackdoor','functionName:')
// This will call the functionName function and pass in the desired parameter, if it exists
- (id *)calabashBackdoor:(NSString *)string
{
    // Break string into a function name and its parameter (if it exists)
    NSArray *userInput = [string componentsSeparatedByString: @":"];
    
    // Method above removes : but the method name must have it, so put it back on the end
    NSString *methodToCall = [NSString stringWithFormat:@"%@:", userInput[0]];
    
    if (userInput.count > 1 && [[CalabashBackdoor class] respondsToSelector:(NSSelectorFromString(methodToCall))])
    {
        return (id *)[[CalabashBackdoor class] performSelector:  NSSelectorFromString(methodToCall) withObject:userInput[1]];
    }
    else if (userInput.count == 1 && [[CalabashBackdoor class] respondsToSelector:(NSSelectorFromString(methodToCall))])
    {
        return (id *)[[CalabashBackdoor class] performSelector:  NSSelectorFromString(methodToCall)];
    }
    else
    {
        NSString *detailsStr = [NSString stringWithFormat:@"You must define the method (selector) '%@' in CalabashBackdoor.\n",
                             methodToCall];
        NSString *usage0 = [NSString stringWithFormat:@"backdoor('calabashBackdoor','%@')",
                            methodToCall];
        NSString *usage1 = [NSString stringWithFormat:@"backdoor('calabashBackdoor','%@<arg>')",
                            methodToCall];
        
        NSString *reasonStr = [NSString stringWithFormat:@"The application delegate does not respond to selector '%@'.",
                               methodToCall];
        
        return (id*) [NSDictionary dictionaryWithObjectsAndKeys:
                      @"FAILURE", @"Outcome",
                      reasonStr, @"Reason for Error",
                      detailsStr, @"Details",
                      usage0, @"Usage for method without a parameter",
                      usage1, @"Usage for method with a parameter",
                      nil];
    }
}

isn't better to have the calabash backdoor defined in a category of the app delegate, and add this category only to the calabash target?