Predicate branching: https://en.wikipedia.org/wiki/Predication_(computer_architecture

PredicateFunctions.h

//
//  PredicateFunctions.h
//  PredicateFunctions
//
//  Created by Xcode Developer on 9/10/22.
//

#ifndef PredicateFunctions_h
#define PredicateFunctions_h

@import Foundation;

typedef typeof(unsigned long)                                  predicate;
typedef typeof(const predicate(^ _Nonnull )(predicate))        predicate_function;
typedef typeof(const predicate(^ _Nonnull const *)(predicate)) predicate_function_t;

predicate_function(^(^synchronous_predicate_functions)(predicate_function))(predicate_function) =  ^ (predicate(^init_func)(predicate)) {
    return ^ (predicate(^inter_func)(predicate)) {
        return ^ predicate (predicate pred) {
            return inter_func(init_func(pred)); // invokes and returns two functions in serial order
        };
    };
};

predicate_function(^(^asynchronous_predicate_functions)(predicate_function))(predicate_function) =  ^ (predicate(^init_func)(predicate)) {
    return ^ (predicate(^inter_func)(predicate)) {
        return ^ predicate (predicate pred) {
            return inter_func(pred) & init_func(pred); // invokes and returns two functions independently
        };
    };
};

predicate_function (^(^(^combine_predicate_functions)(predicate_function))(predicate_function))(predicate_function(^)(predicate_function_t, predicate_function_t, predicate)) =  ^ (predicate_function pred_f) {
    return ^ (predicate_function p_func) {
            return ^ (predicate_function(^evaluation)(predicate_function_t, predicate_function_t, predicate)) {
                return ^ predicate (predicate p) {
                    return evaluation(&pred_f, &p_func, p)(p);
                };
            };
    };
};

static void (^wxyz)(void) = ^{
    predicate_function pf1 = ^ predicate (predicate p) { printf("p == %lu\n", p); return p; };
    predicate_function pf2 = ^ predicate (predicate p) { printf("p == %lu\n", (p = p + 1)); return p; };
    predicate_function pfx = combine_predicate_functions(pf1)(pf2)(^ (predicate_function_t init_func_t, predicate_function_t inter_func_t, predicate pred) {
        return ^ predicate (predicate pred) {
            return (*inter_func_t)((*init_func_t)(pred));
            
        };
    
    // wxyz() will output p = 55 and p = 56 to the console
    pfx(55);
};

#endif /* PredicateFunctions_h */