| \section{Built-in Module \sectcode{ni}} |
| \label{module-ni} |
| \bimodindex{ni} |
| |
| \strong{Warning: This module is obsolete.} As of Python 1.5a4, |
| package support (with different semantics for \code{__init__} and no |
| support for \code{__domain__} or\code{__}) is built in the |
| interpreter. The ni module is retained only for backward |
| compatibility. |
| |
| The \code{ni} module defines a new importing scheme, which supports |
| packages containing several Python modules. To enable package |
| support, execute \code{import ni} before importing any packages. Importing |
| this module automatically installs the relevant import hooks. There |
| are no publicly-usable functions or variables in the \code{ni} module. |
| |
| To create a package named \code{spam} containing sub-modules \code{ham}, \code{bacon} and |
| \code{eggs}, create a directory \file{spam} somewhere on Python's module search |
| path, as given in \code{sys.path}. Then, create files called \file{ham.py}, \file{bacon.py} and |
| \file{eggs.py} inside \file{spam}. |
| |
| To import module \code{ham} from package \code{spam} and use function |
| \code{hamneggs()} from that module, you can use any of the following |
| possibilities: |
| |
| \bcode\begin{verbatim} |
| import spam.ham # *not* "import spam" !!! |
| spam.ham.hamneggs() |
| \end{verbatim}\ecode |
| % |
| \bcode\begin{verbatim} |
| from spam import ham |
| ham.hamneggs() |
| \end{verbatim}\ecode |
| % |
| \bcode\begin{verbatim} |
| from spam.ham import hamneggs |
| hamneggs() |
| \end{verbatim}\ecode |
| % |
| \code{import spam} creates an |
| empty package named \code{spam} if one does not already exist, but it does |
| \emph{not} automatically import \code{spam}'s submodules. |
| The only submodule that is guaranteed to be imported is |
| \code{spam.__init__}, if it exists; it would be in a file named |
| \file{__init__.py} in the \file{spam} directory. Note that |
| \code{spam.__init__} is a submodule of package spam. It can refer to |
| spam's namespace as \code{__} (two underscores): |
| |
| \bcode\begin{verbatim} |
| __.spam_inited = 1 # Set a package-level variable |
| \end{verbatim}\ecode |
| % |
| Additional initialization code (setting up variables, importing other |
| submodules) can be performed in \file{spam/__init__.py}. |