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== Pyximport == Download: pyx-import-1.0.tar.gz <http://www.prescod.net/pyximport/pyximport-1.0.tar.gz> Pyrex is a compiler. Therefore it is natural that people tend to go through an edit/compile/test cycle with Pyrex modules. But my personal opinion is that one of the deep insights in Python's implementation is that a language can be compiled (Python modules are compiled to .pyc) files and hide that compilation process from the end-user so that they do not have to worry about it. Pyximport does this for Pyrex modules. For instance if you write a Pyrex module called "foo.pyx", with Pyximport you can import it in a regular Python module like this: import pyximport; pyximport.install() import foo Doing so will result in the compilation of foo.pyx (with appropriate exceptions if it has an error in it). If you would always like to import pyrex files without building them specially, you can also the first line above to your sitecustomize.py. That will install the hook every time you run Python. Then you can use Pyrex modules just with simple import statements. I like to test my Pyrex modules like this: python -c "import foo" See help(pyximport.install) to learn its options for controlling the default behavior of "import" and "reload". == Dependency Handling == In Pyximport 1.1 it is possible to declare that your module depends on multiple files, (likely ".h" and ".pxd" files). If your Pyrex module is named "foo" and thus has the filename "foo.pyx" then you should make another file in the same directory called "foo.pyxdep". The "modname.pyxdep" file can be a list of filenames or "globs" (like "*.pxd" or "include/*.h"). Each filename or glob must be on a separate line. Pyximport will check the file date for each of those files before deciding whether to rebuild the module. In order to keep track of the fact that the dependency has been handled, Pyximport updates the modification time of your ".pyx" source file. Future versions may do something more sophisticated like informing distutils of the dependencies directly. == Limitations == Pyximport does not give you any control over how your Pyrex file is compiled. Usually the defaults are fine. You might run into problems if you wanted to write your program in half-C, half-Pyrex and build them into a single library. Pyximport 1.2 will probably do this. Pyximport does not hide the Distutils/GCC warnings and errors generated by the import process. Arguably this will give you better feedback if something went wrong and why. And if nothing went wrong it will give you the warm fuzzy that pyximport really did rebuild your module as it was supposed to. == For further thought and discussion == "setup.py install" does not modify sitecustomize.py for you. Should it? Modifying Python's "standard interpreter" behaviour may be more than most people expect of a package they install.. Pyximport puts your ".c" file beside your ".pyx" file (analogous to ".pyc" beside ".py"). But it puts the platform-specific binary in a build directory as per normal for Distutils. If I could wave a magic wand and get Pyrex or distutils or whoever to put the build directory I might do it but not necessarily: having it at the top level is VERY HELPFUL for debugging Pyrex problems.