Block_copy + CFBridgingRetain/Release

poly_blocks.h

/*
 Functors invoked with an argument supplied by the destination
 */
typedef const float (^ const __strong blk)(const float);
blk b = ^ const float (const float f) {
    return f;
};

typedef const void * (^ const __strong blk_t)(blk);
blk_t b_ptr = ^ (blk b) {
    return Block_copy((const void *)CFBridgingRetain(b));
};

typedef blk (^ const __strong functor)(const void *);
functor f = ^ (const void * functor_t) {
    return (blk)CFBridgingRelease((__bridge CFTypeRef _Nullable)((__bridge blk)(functor_t)));
};

/*
 Functors invoked with an argument supplied at the source (returns the uninvoked functor, which can be invoked with 'void' instead of the argument required by the functor)
 */

typedef const float (^(^blk_pack)(const float))(void);
blk_pack bp = ^ (const float f_) {
    return (^ (const float f) {
        return ^ const float {
            return f;
        };
    })(f_);
};

typedef const void * (^ const __strong blk_pack_t)(blk_pack);
blk_pack_t bp_t = ^ (blk_pack bp) {
    return Block_copy((const void *)CFBridgingRetain(bp));
};

typedef blk_pack (^ const __strong functor_pack)(const void *);
functor_pack fp = ^ (const void * functor_pack_t) {
    return (blk_pack)CFBridgingRelease((__bridge CFTypeRef _Nullable)((__bridge blk_pack)(functor_pack_t)));
};