apipkg / README.txt

Welcome to apipkg!

With apipkg you can control the exported namespace of a
python package and greatly reduce the number of imports for your users.
It is a `small pure python module`_ that works on virtually all Python
versions, including CPython2.3 to Python3.1, Jython and PyPy.  It co-operates
well with Python's ``help()`` system, custom importers (PEP302) and common 
command line completion tools.  

Usage is very simple: you can require 'apipkg' as a dependency or you
can copy paste the <100 Lines of code into your project.

Tutorial example

Here is a simple ``mypkg`` package that specifies one namespace
and exports two objects imported from different modules::

    # mypkg/
    import apipkg
    apipkg.initpkg(__name__, {
        'path': {
            'Class1': "_mypkg.somemodule:Class1",
            'clsattr': "_mypkg.othermodule:Class2.attr",

The package is initialized with a dictionary as namespace. 

You need to create a ``_mypkg`` package with a ```` 
and ```` containing the respective classes.
The ``_mypkg`` is not special - it's a completely 
regular python package. 

Namespace dictionaries contain ``name: value`` mappings 
where the value may be another namespace dictionary or
a string specifying an import location.  On accessing
an namespace attribute an import will be performed::

    >>> import mypkg
    >>> mypkg.path
    <ApiModule 'mypkg.path'>
    >>> mypkg.path.Class1   # '_mypkg.somemodule' gets imported now
    <class _mypkg.somemodule.Class1 at 0xb7d428fc>
    >>> mypkg.path.clsattr  # '_mypkg.othermodule' gets imported now
    4 # the value of _mypkg.othermodule.Class2.attr

The ``mypkg.path`` namespace and its two entries are
loaded when they are accessed.   This means:

* lazy loading - only what is actually needed is ever loaded

* only the root "mypkg" ever needs to be imported to get
  access to the complete functionality.

* the underlying modules are also accessible, for example::

    from mypkg.sub import Class1

Including apipkg in your package

If you don't want to add an ``apipkg`` dependency to your package you 
can copy the ``_ file somewhere to your own package, 
for example ``_mypkg/`` in the above example.  You
then import the ``initpkg`` function from that new place and
are good to go. 

.. _`small pure python module`:
.. _``:


If you have questions you are welcome to 

* join the #pylib channel on 
* subscribe to the list. 
* create an issue on

have fun, 
holger krekel