monkey/examples/functional.mon at master · skx/monkey · GitHub

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//
// This script contains some functional programming examples.
//
// Launch this like so:
//
//  ~$ monkey examples/functional.mon
//


//
// Return true if the given number is even
//
function even?(n) {
  return( n % 2 == 0 );
}


//
// Return true if the given number is odd.
//
function odd?(n) {
  return( n % 2 == 1 );
}


/*
 * Return true if the given number is prime
 *
 * Remember we can use multi-line comments too!
 */
function prime?(n) {
   // negative numbers are not prime
   if ( n < 0 ) { return false ; }

   // 0, 1, 2 are prime
   if ( n < 3 ) { return true ; }

   // Now the rest - we're testing all factors between 2 & SQRT(n).
   let i = int(math.sqrt(n)) + 1;

   for( i > 2 ) {
     i--;
     if (n % i == 0) {
        return false;
     }
   }
   return true;
}


//
// Square the given number.
//
function square(n) { return n * n ; }

//
// The list of numbers we'll operate upon.
//
let ints = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
             11, 12, 13, 14, 15, 16, 17, 18, 19, 20 ];

// Show them ..
puts( "\nIntegers:\n" );
puts( "\t", ints, "\n" );

//
// Show their squares ..
//
puts( "\nSquares:\n" );
puts( "\t", ints.map(square), "\n");

//
// Show their cubes, using an anonymous function
//
puts( "\nCubes:\n" );
puts( "\t", ints.map( fn(n) { return n * n * n; }), "\n");
puts( "\nCubes via POW:\n" );
puts( "\t", ints.map( fn(n) { return n ** 3; }), "\n");

//
// Now use our functional-methods to show odd/even/prime
// numbers contained in our list.
//
puts( "\nOdd numbers:\n" );
puts( "\t", ints.filter(odd?), "\n");
puts( "\nEven numbers:\n" );
puts( "\t", ints.filter( even?), "\n");
puts( "\nPrime numbers:\n" );
puts( "\t", ints.filter( prime?), "\n");