//BABY STOOPS TO THE CLINTONS
//Yieldprolog tutorial 1 in c++14


#include <iostream>
#include <string>
#include <functional>
using namespace std;

typedef string& var;

typedef function<bool (var, var)>  comp;

//Coroutine generator for a fact
comp fact(string s, string o) {
  int entry=0;
  return [s,o, entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0: Ds=s; Do=o; entry=1; return true;
	default: return false;
    }
  };
}

//Or optimized specializations for 2,3,N facts...

comp fact2(string s, string o, string s2, string o2) {
  int entry=0;
  return [s,o, s2, o2, entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0: Ds=s; Do=o; entry=1; return true;
      case 1: Ds=s2; Do=o2; entry=2; return true;
	default: return false;
    }
  };
}

comp fact3(string s, string o, string s2, string o2, string s3, string o3) {
  int entry=0;
  return [s,o, s2, o2, s3, o3, entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0: Ds=s; Do=o; entry=1; return true;
      case 1: Ds=s2; Do=o2; entry=2; return true;
      case 2: Ds=s3; Do=o3; entry=3; return true;
	default: return false;
    }
  };
}

comp fact4(string s, string o, string s2, string o2, string s3, string o3, string s4, string o4) {
  int entry=0;
  return [s,o, s2, o2, s3, o3, s4, o4, entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0: Ds=s; Do=o; entry=1; return true;
      case 1: Ds=s2; Do=o2; entry=2; return true;
      case 2: Ds=s3; Do=o3; entry=3; return true;
      case 3: Ds=s4; Do=o4; entry=4; return true;
	default: return false;
    }
  };
}

comp fact5(string s, string o, string s2, string o2, string s3, string o3, string s4, string o4, string s5, string o5) {
  int entry=0;
  return [s,o, s2, o2, s3, o3, s4, o4, s5, o5, entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0: Ds=s; Do=o; entry=1; return true;
      case 1: Ds=s2; Do=o2; entry=2; return true;
      case 2: Ds=s3; Do=o3; entry=3; return true;
      case 3: Ds=s4; Do=o4; entry=4; return true;
      case 4: Ds=s5; Do=o5; entry=5; return true;
	default: return false;
    }
  };
}

comp fact6(string s, string o, string s2, string o2, string s3, string o3, string s4, string o4, string s5, string o5, string s6, string o6) {
  int entry=0;
  return [s,o, s2, o2, s3, o3, s4, o4, s5, o5, s6, o6, entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0: Ds=s; Do=o; entry=1; return true;
      case 1: Ds=s2; Do=o2; entry=2; return true;
      case 2: Ds=s3; Do=o3; entry=3; return true;
      case 3: Ds=s4; Do=o4; entry=4; return true;
      case 4: Ds=s5; Do=o5; entry=5; return true;
      case 5: Ds=s6; Do=o6; entry=6; return true;
	default: return false;
    }
  };
}

//Sequencing combinator

comp seq(comp a, comp b) {
  int entry=0;
  return [a,b,entry](var Ds, var Do) mutable {
    switch(entry) {
      case 0:
      while(a(Ds, Do)) {
        entry=1; return true;
        case 1: ;
      }
      while(b(Ds, Do)) {
        entry=2; return true;
        case 2: ;
      }
      entry=3;
      default: return false;
    }
  };
}

//join combinators

comp joinavvb(comp a, comp b, var v) {
  int entry=0;
  return [a, b, v, entry](var Ds, var Do) mutable {
	switch(entry) {
	  case 0: while(a(Ds, v)) {
	    while(b(v, Do)) {
	      entry=1; return true;
	      case 1: ;
	    }
	    entry=2;
	  default:
	    return false;
	  }
	}
  };
}


comp joinavvb(comp a, comp b) {
	string v;
	return joinavvb(a, b, v);
}

comp joinvabv(comp a, comp b, var v) {
  int entry=0;
  return [a, b, v, entry](var Ds, var Do) mutable {
	switch(entry) {
	  case 0: while(a(v, Do)) {
	    while(b(Ds, v)) {
	      entry=1; return true;
	      case 1: ;
	    }
	    entry=2;
	  default:
	    return false;
	  }
	}
  };
}


comp joinvabv(comp a, comp b) {
	string v;
	return joinvabv(a, b, v);
}

//TODO: Others...

comp joinvavb(comp a, comp b, var v){
  int entry=0;
  return [a, b, v, entry](var Ds, var Do) mutable {
	switch(entry) {
	  case 0: while(a(v, Do)) {
	    while(b(v, Ds)) {
	      entry=1; return true;
	      case 1: ;
	    }
	    entry=2;
	  default:
	    return false;
	  }
}

comp joinvavb(comp a, comp b){
	string v;
	return joinvavb(a,b,v);
}

comp joinavbv(comp a, comp b, var v){
  int entry=0;
  return [a, b, v, entry](var Ds, var Do) mutable {
	switch(entry) {
	  case 0: while(a(Do, v)) {
	    while(b(Ds,v)) {
	      entry=1; return true;
	      case 1: ;
	    }
	    entry=2;
	  default:
	    return false;
	  }
}

comp joinavbv(comp a, comp b){
	string v;
	return joinavbv(a,b,v);
}

//an example clintons
int main() {
  string _Person = "Person";
  string _Bill = "Bill";
  string _Hillary = "Hillary";
  string _Tony = "Tony";
  string _Chelsea = "Chelsea";
  string _Roger = "Roger";
  string _Hugh = "Hugh";

  comp a = fact6(
  	_Bill, _Person, _Hillary, _Person,
  	_Tony, _Person, _Chelsea, _Person,
  	_Roger, _Person, _Hugh, _Person);
  comp bro = fact3(_Hillary, _Tony, _Hillary, _Hugh, _Bill, _Roger); //or a seq of fact2 and fact1 or something
  comp parent = fact2(_Chelsea, _Hillary, _Chelsea, _Bill);
  comp uncle = joinavvb(parent, bro);

  comp unclesubjppl = joinvabv(a, joinavvb(parent, bro));

  string l, r;
  while(uncle(l,r)) {
    cout << l << " uncle " << r << endl;
  }
  cout << "=======" << endl;
  while(unclesubjppl(l,r)) {
    cout << l << " unclesubjppl " << r << endl;
  }

}