#import <Foundation/Foundation.h>

typedef NSString *(^CALLABLE_TO_STRING)(id);
typedef NSNumber *(^CALLABLE_TO_NUMBER)(id);
typedef NSString *(^ACCUMULATOR_TO_STRING)(id, id);

@interface Callables : NSObject
+ (id (^)(id))identity;

+ (NSString * (^)(NSString *))toUpperCase;

+ (NSString * (^)(NSString *, NSString *))appendString;

+ (ACCUMULATOR_TO_STRING)appendWithSeparator:(NSString *)separator;

+ (CALLABLE_TO_STRING)upperCase;

+ (CALLABLE_TO_NUMBER)increment;
@end

static CALLABLE_TO_STRING TL_upperCase() {
    return [Callables upperCase];
}

static ACCUMULATOR_TO_STRING TL_appendWithSeparator(NSString *separator) {
    return [Callables appendWithSeparator:separator];
}

static CALLABLE_TO_NUMBER TL_increment() {
    return [Callables increment];
}