こんなの書いてた。自分で言うのもなんですが、何これキモいと思いました。

gistfile1.m

@interface Tuple : NSObject

@property (readonly, nonatomic) id _1;
@property (readonly, nonatomic) id _2;

+ (id)tupleWithFirst:(id)_1 second:(id)_2;
- (id)initWithFirst:(id)_1 second:(id)_2;

@end

@implementation Tuple

+ (id)tupleWithFirst:(id)_1 second:(id)_2 {
    return [[self alloc] initWithFirst:_1 second:_2];
}
- (id)initWithFirst:(id)_1 second:(id)_2 {
    self = [super init];
    if (self) {
        __1 = _1;
        __2 = _2;
    }
    return self;
}

@end

#define tuple(x, y) [Tuple tupleWithFirst:(x) second:(y)];

@implementation NSObject (typeMatch)

@end
#define lambda(x, code) (^(id x){return ({ code ;});})
#define lambda2(x, y, code) (^(id x, id y){return ({ code ;});})

#define Case(code1, code2) [Tuple tupleWithFirst:(lambda(it, @(code1))) second:(lambda(it, code2))]
#define typeCase(type, code) Case([it isKindOfClass:[type class]], code)
#define eqCase(eq, code) Case([it isEqual:eq], code)
#define ifCase(if, code) Case(if, code)
#define other(code) [Tuple tupleWithFirst:lambda(it, @(YES)) second:lambda(it, code)]

#define pMatch (id)^(id __a, id __t) { id(^__m)(id) = [__t _1]; id(^__n)(id) = [__t _2]; return ([__m(__a) boolValue]) ? __n(__a) : nil; }
#define pMatch2 (id)^(id __a, id __t, id __t2) { return (pMatch(__a, __t)) ?: pMatch(__a, __t2); }
#define pMatch3 (id)^(id __a, id __t, id __t2, id __t3) { return (pMatch(__a, __t)) ?: pMatch2(__a, __t2, __t3); }
#define pMatch4 (id)^(id __a, id __t, id __t2, id __t3, id __t4) { return (pMatch(__a, __t)) ?: pMatch3(__a, __t2, __t3, __t4); }

//- (void)testMatch {
//    NSString *str1 = @"hoge";
//    
//    id re = pMatch4(str1,
//        typeCase(NSNumber, @([it integerValue] * 2)),
//        eqCase(@"fuga", [it stringByAppendingString:it]),
//        ifCase([@"hoge" compare:it] == NSOrderedAscending, @([it length])),
//        other(it)
//    );
//    
//    STAssertEqualObjects(@"hoge", re, @"same");
//}