Scan
====

.. testsetup:: *

    from iterplus import scan

"scan" provides simple means to define various types of series. The following examples illustrate this better.

Incremental Scan
^^^^^^^^^^^^^^^^

.. doctest::

    >>> pos_list = scan(1, 2) # returns a generator

    >>> pos_list.next()
    1

    >>> pos_list.next()
    2

    >>> pos_list.next()
    3

Decremental Scan
^^^^^^^^^^^^^^^^

.. doctest::

    >>> neg_list = scan(-2, -5)

    >>> neg_list.next()
    -2

    >>> neg_list.next()
    -5

    >>> neg_list.next()
    -8

Constant Scan
^^^^^^^^^^^^^

.. doctest::

    >>> c_list = scan(7, 7)

    >>> c_list.next()
    7

    >>> c_list.next()
    7

    >>> c_list.next()
    7

Custom Rule
^^^^^^^^^^^

.. doctest::

    >>> fibo = scan(0, 1, lambda a, b: a + b)

    >>> fibo.next()
    0

    >>> fibo.next()
    1

    >>> fibo.next()
    1

    >>> fibo.next()
    2