Metadata-Version: 1.0
Name: fn
Version: 0.1.13
Summary: Implementation of missing features to enjoy functional programming in Python
Home-page: https://github.com/kachayev/fn.py
Author: Alexey Kachayev
Author-email: kachayev@gmail.com
License: Copyright 2013 Alexey Kachayev

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

Description: Fn.py: enjoy FP in Python
        =========================
        
        Despite the fact that Python is not pure-functional programming
        language, it's multi-paradigm PL and it gives you enough freedom to take
        credits from functional programming approach. There are theoretical and
        practical advantages to the functional style:
        
        -  Formal provability
        -  Modularity
        -  Composability
        -  Ease of debugging and testing
        
        ``Fn.py`` library provides you with missing "batteries" to get maximum
        from functional approach even in mostly-imperative program.
        
        More about functional approach from my Pycon UA 2012 talks: `Functional
        Programming with
        Python <http://ua.pycon.org/static/talks/kachayev/#/>`_.
        
        Scala-style lambdas definition
        ------------------------------
        
        .. code-block:: python
        
            from fn import _
            from fn.iters import zipwith
            from itertools import repeat
        
            assert list(map(_ * 2, range(5))) == [0,2,4,6,8]
            assert list(filter(_ < 10, [9,10,11])) == [9]
            assert list(zipwith(_ + _)([0,1,2], repeat(10))) == [10,11,12]
        
        More examples of using ``_`` you can find in `test
        cases <https://github.com/kachayev/fn.py/blob/master/tests.py>`_
        declaration (attributes resolving, method calling, slicing).
        
        Streams and infinite sequences declaration
        ------------------------------------------
        
        Lazy-evaluated scala-style streams. Basic idea: evaluate each new
        element "on demand" and share calculated elements between all created
        iterators. ``Stream`` object supports ``<<`` operator that means pushing
        new elements when it's necessary.
        
        Simplest cases:
        
        .. code-block:: python
        
            from fn import Stream
        
            s = Stream() << [1,2,3,4,5]
            assert list(s) == [1,2,3,4,5]
            assert s[1] == 2
            assert s[0:2] == [1,2]
        
            s = Stream() << range(6) << [6,7]
            assert list(s) == [0,1,2,3,4,5,6,7]
        
            def gen():
                yield 1
                yield 2
                yield 3
        
            s = Stream() << gen << (4,5)
            assert list(s) == [1,2,3,4,5]
        
        Lazy-evaluated stream is useful for infinite sequences, i.e. fibonacci
        sequence can be calculated as:
        
        .. code-block:: python
        
            from fn import Stream
            from fn.iters import take, drop, map
            from operator import add
        
            f = Stream()
            fib = f << [0, 1] << map(add, f, drop(1, f))
        
            assert list(take(10, fib)) == [0,1,1,2,3,5,8,13,21,34]
            assert fib[20] == 6765
            assert fib[30:35] == [832040,1346269,2178309,3524578,5702887]
        
        High-level operations with functions
        ------------------------------------
        
        ``fn.F`` is a useful function wrapper to provide easy-to-use partial
        application and functions composition.
        
        .. code-block:: python
        
            from fn import F, _
            from operator import add, mul
        
            # F(f, *args) means partial application 
            # same as functools.partial but returns fn.F instance
            assert F(add, 1)(10) == 11
        
            # F << F means functions composition,
            # so (F(f) << g)(x) == f(g(x))
            f = F(add, 1) << F(mul, 100)
            assert list(map(f, [0, 1, 2])) == [1, 101, 201]
            assert list(map(F() << str << (_ ** 2) << (_ + 1), range(3))) == ["1", "4", "9"]
        
        You can find more examples for compositions usage in ``fn._``
        implementation `source
        code <https://github.com/kachayev/fn.py/blob/master/fn/underscore.py>`_.
        
        ``fn.op.apply`` executes given function with given positional arguments
        in list (or any other iterable). ``fn.op.flip`` returns you function
        that will reverse arguments order before apply.
        
        .. code-block:: python
        
            from fn.op import apply, flip
            from operator import add, sub
        
            assert apply(add, [1, 2]) == 3
            assert flip(sub)(20,10) == -10
            assert list(map(apply, [add, mul], [(1,2), (10,20)])) == [3, 200]
        
        Itertools recipes
        -----------------
        
        ``fn.iters`` module consists from two parts. First one is "unification"
        of lazy functionality for few functions to work the same way in Python
        2+/3+:
        
        -  ``map`` (returns ``itertools.imap`` in Python 2+)
        -  ``filter`` (returns ``itertools.ifilter`` in Python 2+)
        -  ``reduce`` (returns ``functools.reduce`` in Python 3+)
        -  ``zip`` (returns ``itertools.izip`` in Python 2+)
        -  ``range`` (returns ``xrange`` in Python 2+)
        -  ``filterfalse`` (returns ``itertools.ifilterfalse`` in Python 2+)
        -  ``zip_longest`` (returns ``itertools.izip_longest`` in Python 2+)
        
        Second part of module is high-level recipes to work with iterators. Most
        of them taken from `Python
        docs <http://docs.python.org/2.7/library/itertools.html#itertools.product>`_
        and adopted to work both with Python 2+/3+. Such recipes as ``drop``,
        ``takelast``, ``droplast``, ``splitat``, ``splitby`` I have already
        submitted as `docs patch <http://bugs.python.org/issue16774>`_ which is
        review status just now.
        
        -  ``take``, ``drop``
        -  ``takelast``, ``droplast``
        -  ``head``, ``tail``
        -  ``consume``
        -  ``nth``
        -  ``padnone``, ``ncycles``
        -  ``repeatfunc``
        -  ``grouper``, ``powerset``, ``pairwise``
        -  ``roundrobin``
        -  ``partition``, ``splitat``, ``splitby``
        -  ``flatten``
        -  ``zipwith``
        -  ``iter_except``
        
        More information about use cases you can find in docstrings for each
        function in `source
        code <https://github.com/kachayev/fn.py/blob/master/fn/iters.py>`_ and
        in `test
        cases <https://github.com/kachayev/fn.py/blob/master/tests.py>`_.
        
        Functional style for error-handling
        -----------------------------------
        
        -  Maybe
        -  Either
        
        **TODO: Implementation, code samples**
        
        Trampolines decorator
        ---------------------
        
        Workaround for dealing with TCO without heavy stack utilization.
        
        **TODO: Implementation, code samples and documented theory.**
        
        Installation
        ------------
        
        To install ``fn.py``, simply:
        
        .. code-block:: console
        
            $ pip install fn
        
        Or, if you absolutely must:
        
        .. code-block:: console
        
            $ easy_install fn
        
        You can also build library from source
        
        .. code-block:: console
        
            $ git clone https://github.com/kachayev/fn.py.git
            $ cd fn.py
            $ python setup.py install
        
        Work in progress (!)
        --------------------
        
        "Roadmap":
        
        -  Error handling (``Maybe``, ``Either`` from Haskell, ``Option`` from
           Scala etc)
        -  Trampolines decorator
        -  Add to ``fn.iters`` module ``foldl``, ``foldr``, ``findelem``,
           ``findindex``
        -  C-accelerator for most modules
        
        Ideas to think about:
        
        -  "Pipeline" notation for composition (back-order):
           ``F() >> list >> partial(map, int)``
        -  Curried function builder to simplify
           ``lambda arg1: lambda arg2: ...``
        -  Scala-style for-yield loop to simplify long map/filter blocks
        
        Contribute
        ----------
        
        1. Check for open issues or open a fresh issue to start a discussion
           around a feature idea or a bug.
        2. Fork the repository on Github to start making your changes to the
           master branch (or branch off of it).
        3. Write a test which shows that the bug was fixed or that the feature
           works as expected.
        
        
        History
        =======
        
        18.01.2012
        ----------
        
        -  Added 22 itertools recipes to ``fn.iters``
        
        17.01.2012
        ----------
        
        -  Unit tests coverage for ``fn.stream.Stream``
        -  ``_StreamIterator`` works fine both in Python 2/3
        
        16.01.2012
        ----------
        
        -  Finished underscore module functionality
        -  Test cases for all implemented modules/functions
        -  Update in Readme file with several fixes
        -  Get rid of F.flip classmethod in pref. for simple building blocks
        -  Optimized version for fn.op.flip operator
        
        14.01.2012
        ----------
        
        -  Simplest ``Stream`` implementation
        -  Code samples for streams, labdas (``_``) and functions compositions
        -  Plan, contribute section in readme file
        
        13.01.2012
        ----------
        
        -  Full list of ideas on paper
        -  Repository is created
        -  Initial commit
        
Platform: UNKNOWN
Classifier: Development Status :: 2 - Pre-Alpha
Classifier: Intended Audience :: Developers
Classifier: Natural Language :: English
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.1
Classifier: Programming Language :: Python :: 3.2
Classifier: Programming Language :: Python :: 3.3
