Gentools

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Tools for generators, generator functions, and generator-based coroutines.

Key features:

• Create reusable generators
• Compose generators
• Build python 2/3-compatible generators (gentools version <1.2 only)

Installation

.. code-block:: bash

pip install gentools

Examples

• Make generator functions reusable:

.. code-block:: python

@reusable ... def countdown(value, step): ... while value > 0: ... yield value ... value -= step

from_3 = countdown(3, step=1) list(from_3) [3, 2, 1] list(from_3) [3, 2, 1] isinstance(from_3, countdown) # generator func is wrapped in a class True from_3.step # attribute access to arguments 1 from_3.replace(value=5) # create new instance with replaced fields countdown(value=5, step=1) # descriptive repr()

• map a generator's yield, send, and return values:

.. code-block:: python

@map_return('final value: {}'.format) ... @map_send(int) ... @map_yield('the current max is: {}'.format) ... def my_max(value): ... while value < 100: ... newvalue = yield value ... if newvalue > value: ... value = newvalue ... return value

gen = my_max(5) next(gen) 'the current max is: 5' gen.send(11.3) 'the current max is: 11' gen.send(104) StopIteration('final value: 104')

• relay a generator's yield/send interactions through another generator:

.. code-block:: python

def try_until_positive(outvalue): ... value = yield outvalue ... while value < 0: ... value = yield 'not positive, try again' ... return value

@relay(try_until_positive) ... def my_max(value): ... while value < 100: ... newvalue = yield value ... if newvalue > value: ... value = newvalue ... return value

gen = my_max(5) next(gen) 5 gen.send(-4) 'not positive, try again' gen.send(-1) 'not positive, try again' gen.send(8) 8 gen.send(104) StopIteration(104)

• make python 2/3 compatible generators with return. (gentools version <1.2 only)

.. code-block:: python

@py2_compatible ... def my_max(value): ... while value < 100: ... newvalue = yield value ... if newvalue > value: ... value = newvalue ... return_(value)