typedef NS_ENUM(NSInteger, Season)  {
    Summer = 1, Fall = 2,
    Winter = 3, Spring = 4
};

@interface NSString (EnumParser)
-(Season) seasonFromString;
@end

@implementation NSString (EnumParser)
-(Season) seasonFromString{
    NSDictionary<NSString*,NSNumber*> *seasons =
    @{
        @"Summer": @(Summer),
        @"Fall": @(Fall),
        @"Winter": @(Winter),
        @"Spring": @(Spring),
        };
    return seasons[self].integerValue;
}
@end

Season winter = [@"Winter" seasonFromString];
//winter is Season.Winter (3)