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.

>>> 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.

>>> 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

>>> 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.

>>> 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.

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