A few useful links
Python home pages
Apple's Cocoa Developer
pages
The Python Objective C project
home page
Fink allows automated installation
and updates of python and loads of other unix opensource and GNU free software
ScientificPython
modules
Numeric Python
modules
This
is better than the
first edition.
This is just better.
There
are several python books
available from O'Reilly and other publishers. I still haven't found
one that I really like.
My main scientific computational interest is in X-ray
crystallographic structural studies of biological macromolecules. Here
is my web page called crystallography
on OS X.
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Introductory Comments
Python is a scripting or interpreting language that is quite powerful
and has lucid syntax, which means it is less painful to read and learn
than fortran.
Cocoa is the the full fledged Mac OS X framework that
one uses to create OS X native applications. Its preferred language
is Objective C, which is said to be a superset of C, and from my point of
view appears to be even more obtuse than C. However, bridges to Java and
Applescript are also available for writing Cocoa applications, and now, thanks
to the PyObjC project, Python is now available as well.
PyObjC creates a bridge between Cocoa and Python, thus
in principle makes available the myriad of python modules to Cocoa programmers
on OS X. From my point of view, I am hoping it will allow me to jump-start
the process of writing useful scientific applications, or at least enable
me to stitch together other people's useful scientific applications.
Getting Started
Download the pyobjc
disk image and install it as you would any normal OS X application.
This automatically installs the relevant files in the Developer tools
directory as well as several subdirectories in the OS X v. 10.2.x system
python under /usr/lib/python2.2/site-packages/ This
is fine if you only need to make use of the system-supplied python. However
if you have used fink to install large numbers of site-packages like I
have, you may want to do the following:
How
to Use Python installed by Fink with PyObjC:
1. Change the
line /usr/bin/python to /sw/bin/python
in the supplied template file /Developer/ProjectBuilder Extras/Project
Templates/Application/Cocoa-Python Application/bin-python-main.m
2. Make the
AddressBook/ AppKit/ Foundation/ and
objc/ directories available to your fink python
installation by doing any one of the following:
a. cp
-R /usr/lib/python2.2/site-packages/* /sw/lib/python2.2/site-packages/
b. symbolically
link /usr/lib/python2.2/site-packages to /sw/lib/python2.2/site-packages
prior to installing pyobjc
c. symbolically
link each of the four subdirectories under /usr/lib/python2.2/site-packages/
to the corresponding files under /sw/lib/python2.2/site-packages/
after installing pyobjc
d. Install
the source (obtained from cvs) to pyobjc in /sw/lib/python2.2/site-packages/
manually using sudo /sw/bin/python setup.py
install
Links to Some Worked
Examples
These will appear as additional pages as I work through them. My initial
plan (subject to revision) is to follow along the lines of Building Cocoa
Applications, but to write the code in Python. Then if that works
I will try to get more ambitious. It would be great if people who, unlike
me, actually know what they are doing, critique this along the way. My
hope is that in addition to enjoying the spectacle of self-inflicted public
embarrassment and humiliation, the reader might find this to be of some use,
at least until someone writes a book (hint).
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