C-Style For-Loops as Python Classes

Because that's totally a thing you wanted.

Basic Usage

Loop lets you write C-style loops in the bodies of Python classes.

.. code-block:: python

from loop import Loop class For(Loop): ... x = 0; x < 5; ++x ... print("Body:", x) ... Body: 0 Body: 1 Body: 2 Body: 3 Body: 4

Control Flow

Inside the body of the loop, you can call break_() and continue_() to break and continue the loop execution.

.. code-block:: python

class For(Loop): ... x = 0; x < 5; ++x ... if x == 2: ... print("Skipping 2") ... continue_() ... print("Body:", x) ... Body: 0 Body: 1 Skipping 2 Body: 3 Body: 4

.. code-block:: python

class For(Loop): ... x = 0; x < 5; ++x ... if x == 2: ... print("Breaking on 2") ... break_() ... print("Body:", x) ... Body: 0 Body: 1 Breaking on 2

Edge Case Handling

Loop correctly handle tricky edge cases.

Loop Condition Never True

If the loop condition is initially False, the loop body is never executed.

.. code-block:: python

   >>> iters = []
   >>> class For(Loop):
   ...     x = 0; x > 100; ++x
   ...     iters.append(x)
   ...
   >>> iters
   []

Loops Inside Functions
~~~~~~~~~~~~~~~~~~~~~~

``Loop`` bodies can refer to local variables of enclosing functions.

.. code-block:: python

>>> def func():
...     iters = []
...     class For(Loop):
...         x = 0; x < 5; ++x
...         iters.append(x)
...     return iters
...
>>> func()
[0, 1, 2, 4, 4]