Objective-C Currying

gistfile1.m

@interface NSObject (Curry)
- (id)curry:(SEL)selector;
@end

@implementation NSObject (Curry)
- (id)curry:(SEL)selector {
    NSMethodSignature *signature = [[self class] instanceMethodSignatureForSelector:selector];
    if (signature) {
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
        invocation.selector = selector;
        invocation.target = self;
        
        NSScanner *scanner = [NSScanner scannerWithString:NSStringFromSelector(selector)];
        int argsCount = 0;
        while (![scanner isAtEnd]) {
            if ([scanner scanUpToString:@":" intoString:nil]) {
                argsCount++;
            }
            [scanner scanString:@":" intoString:nil];
        }
        
        __block int index = 0;
        __block id (^f)(void *) = ^(void *arg) {
            [invocation setArgument:&arg atIndex:index + 2];
            
            index++;
            if (index == argsCount) {
                [invocation invoke];
                void *returnValue;
                [invocation getReturnValue:&returnValue];
                return (__bridge_transfer id)returnValue;
            } else {
                return f;
            }
        };
        
        return f;
    } else {
        return nil;
    }
}
@end

@interface NSString (Extras)
- (id)first:(NSString *)str1 second:(NSString *)str2 third:(NSString *)str3;
@end

@implementation NSString (Extras)
- (id)first:(NSString *)str1 second:(NSString *)str2 third:(NSString *)str3 {
    return [self stringByAppendingFormat:@" %@ %@ %@", str1, str2, str3];
}
@end

int main (int argc, const char * argv[]) {
    @autoreleasepool {
        NSString *str = @"test";
        id (^f)(void *) = [str curry:@selector(first:second:third:)];
        f = f(@"1");
        f = f(@"2");
        NSLog(@"%@", f(@"3"));
    }
    return 0;
}