| 'DOCUMENTATION' | ~~
  the @reduce library allows you to reduce RPN expressions
  that are enclosed within curly braces inside of a tuple .
  here's an example of how to use it :

  '' (@reduce snake = x is { 2 3 + 4 * } and y is { 10 7 - } .)

  this will result in the following :

  'snake' x is 20 and y is 3

  also note that you can replace the stack name with @main to
  push the result to the main stack .


| '' (@reduce .) | '' convert output stack to tuple
| '' @reduce? '' ($stack =) | 'destination' $stack
| '' @reduce? '' ({ }) 'numbers' $result | 'output' $result

| '' @reduce? '' {? '' + 'numbers' ($b $a) | '@js' f("numbers", "" + (Number($a) + Number($b)));
| '' @reduce? '' {? '' - 'numbers' ($b $a) | '@js' f("numbers", "" + (Number($a) - Number($b)));
| '' @reduce? '' {? '' * 'numbers' ($b $a) | '@js' f("numbers", "" + (Number($a) * Number($b)));
| '' @reduce? '' {? '' / 'numbers' ($b $a) | '@js' f("numbers", "" + (Number($a) / Number($b)));

| '' @reduce? '' {? '' random 'numbers' ($max $min) | '@js'
  const min = Number($min), max = Number($max);
  f("numbers", min + Math.floor(Math.random() * (max - min)));

| '' @reduce? '' {? '' wrap 'numbers' ($max $min $a) | '@js'
  const a = Number($a), min = Number($min), max = Number($max);
  let result = a;
  if (a < min) result = max;
  if (a > max) result = min;
  f("numbers", result);

| '' @reduce? '' {? '' $number| 'numbers' $number
| '' @reduce? '' $word | 'output' $word


| '' convert $stack stack to tuple 'destination' $destination | '@js'
  let destination = $destination == "@main" ? "" : $destination;
  f(destination, ...stacks[$stack].map(fact => fact.join(" ")));
  delete stacks[$stack];