Examples
========


Calculating Pi with Monte Carlo Method
--------------------------------------

Pseudo-random number generator with :py:class:`~hymn.types.state.State` monad:

.. literalinclude:: ../examples/monte_carlo.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./monte_carlo.hy 50000
  the estimate for pi = 3.14232


Calculating Sum
---------------

Wicked sum function with :py:class:`~hymn.types.writer.Writer` monad:

.. literalinclude:: ../examples/sum.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./sum.hy 123 456 789
  sum: 1368


Interactive Greeting
--------------------

Greeting from :py:class:`~hymn.types.continuation.Continuation` monad:

.. literalinclude:: ../examples/greeting.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./greeting.hy
  Hi, what is your name?
  Please tell me your name!
  $ ./greeting.hy
  Hi, what is your name? Marvin
  Welcome, Marvin!


Greatest Common Divisor
-----------------------

Logging with :py:class:`~hymn.types.writer.Writer` monad:

.. literalinclude:: ../examples/gcd.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./gcd.hy 24680 1352
  calculating the greatest common divisor of 24680 and 1352
  24680 mod 1352 = 344
  1352 mod 344 = 320
  344 mod 320 = 24
  320 mod 24 = 8
  24 mod 8 = 0
  the result is: 8


Project Euler Problem 9
-----------------------

Solving problem 9 with :py:class:`~hymn.types.list.List` monad

.. literalinclude:: ../examples/euler9.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./euler9.hy
  Project Euler Problem 9 - list monad example
  https://projecteuler.net/problem=9
  There exists exactly one Pythagorean triplet
  for which a + b + c = 1000.  Find the product abc.
  31875000


Project Euler Problem 29
------------------------

Solving problem 29 with :py:func:`~hymn.operations.lift` and
:py:class:`~hymn.types.list.List` monad

.. literalinclude:: ../examples/euler29.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./euler29.hy
  Project Euler Problem 29 - lift and list monad example
  https://projecteuler.net/problem=29
  How many distinct terms are in the sequence generated by
  a to the power of b for 2 <= a <= 100 and 2 <= b <= 100?
  9183


Solving 24 Game
---------------

Nondeterministic computation with :py:class:`~hymn.types.list.List` monad and
error handling with :py:class:`~hymn.types.maybe.Maybe` monad:

.. literalinclude:: ../examples/solve24.hy
  :language: clojure
  :lines: 7-

Example output:

.. code-block:: sh

  $ ./solve24.hy 2 3 8 8
  ((2 * 8) - 8) * 3
  (3 / 2) * (8 + 8)
  3 / (2 / (8 + 8))
  ((8 - 2) - 3) * 8
  ((8 * 2) - 8) * 3
  ((8 - 3) - 2) * 8
  8 * (8 - (2 + 3))
  ((8 + 8) / 2) * 3
  (8 + 8) / (2 / 3)
  (8 + 8) * (3 / 2)
  8 * (8 - (3 + 2))
  ((8 + 8) * 3) / 2