//Purpose:
//  Use monad to do haskell type list comprehension 
//  as demonstrated here:
//
//    http://www.muitovar.com/monad/moncow.xhtml#list
//
//  Actually, the document:
//
//    http://www-static.cc.gatech.edu/~yannis/fc++/fcpp-lambda.pdf
//
//  gives some example of list comprehension; hence, I only need
//  to mimic that to test the ideas.  There even may be some example
//  files using compM (the list comprehension monad mention around
//  p. 23 of fcpp-lambda.pdf).
//
//ChangeLog:
//  2009-06-17:
//    cp'ed some code from monad.cc downloaded in:
//      FC++-clients.1.5.tar.gz
//    from:
//      http://sourceforge.net/project/downloading.php?group_id=140353&filename=FC%2B%2B-clients.1.5.tar.gz
//    on:
//      2009-05-11.0938
//

#include <iostream>
#include <map>
#define FCPP_ENABLE_LAMBDA
#include "prelude.h"

using namespace fcpp;

using std::cout;
using std::endl;

int main() 
{
   LambdaVar<1> X;
   LambdaVar<2> Y;

   cout << "---------:" << __LINE__ << endl;
   {
       List<std::pair<int,int> > l =
         lambda()
         [ compM<ListM>()
           [ makePair[X,Y] 
           | (X <= list_with(1,2))
           , (Y <= list_with(3,4))
           ]
         ]();
       while( !null(l) ) {
          cout << head(l).first << "," << head(l).second << endl;
          l = tail(l);
       }
       
   }
   cout << "---------" << endl;

   return 0;
}