Building and using a framework-based Python on Mac OS X. -------------------------------------------------------- This document provides a quick introduction to framework-based Python, its advantages, and how to build it. 1. Why would I want a framework Python in stead of a normal static Python? -------------------------------------------------------------------------- The main reason is because you want to create GUI programs in Python. With the exception of X11/XDarwin-based GUI toolkits it appears that all GUI programs need to be run from a fullblown MacOSX application (a ".app" bundle). While it is technically possible to create a .app without using frameworks you will have to do the work yourself if you really want this. A second reason for using frameworks is that they put Python-related items in only two places: /Library/Framework/Python.framework and /Applications/MacPython-2.3. This simplifies matters for users installing Python from a binary distribution if they want to get rid of it again. Moreover, due to the way frameworks work a user without admin privileges can install a binary distribution in his or her home directory without recompilation. Incidentally, the procedure described here is also the procedure that is used to create the MacPython binary installer, so the information here should theoretically allow you to rebuild that. 2. How does a framework Python differ from a normal static Python? ------------------------------------------------------------------ In everyday use there is no difference, except that things are stored in a different place. If you look in /Library/Frameworks/Python.framework you will see lots of relative symlinks, see the Apple documentation for details. If you are used to a normal unix Python file layout go down to Versions/Current and you will see the familiar bin and lib directories. 3. Do I need extra packages? ---------------------------- Yes, probably. If you want to be able to use the PythonIDE you will need to get Waste, an all-singing-all-dancing TextEdit replacement, from www.merzwaren.com. It will unpack into a folder named something like "Waste 2.1 Distribution". Make a symlink called "waste" to this folder, somewhere beside your Python source distribution (it can be "../waste", "../../waste", etc). If you want Tkinter support you need to get the OSX AquaTk distribution. If you want wxPython you need to get that. If you want Cocoa you need to get pyobjc. Because all these are currently in a state of flux please refer to http://www.cwi.nl/~jack/macpython.html, which should contain pointers to more information. 4. How do I build a framework Python? ------------------------------------- This directory contains a Makefile that will create a couple of python-related applications (fullblown OSX .app applications, that is) in /Applications/MacPython-2.3, and a hidden helper application Python.app inside the Python.framework, and unix tools "python" and "pythonw" into /usr/local/bin. In addition it has a target "installmacsubtree" that installs the relevant portions of the Mac subtree into the Python.framework. It is normally invoked indirectly through the main Makefile, as the last step in the sequence 1. ./configure --enable-framework 2. make 3. make frameworkinstall This sequence will put the framework in /Library/Framework/Python.framework, the applications in /Applications/Python and the unix tools in /usr/local/bin. Installing in another place, for instance $HOME/Library/Frameworks if you have no admin privileges on your machine, has only been tested very lightly. This can be done by configuring with --enable-framework=$HOME/Library/Frameworks. The other two directories, /Applications/MacPython-2.3 and /usr/local/bin, will then also be deposited in $HOME. This is sub-optimal for the unix tools, which you would want in $HOME/bin, but there is no easy way to fix this right now. Note that there are no references to the actual locations in the code or resource files, so you are free to move things around afterwards. For example, you could use --enable-framework=/tmp/newversion/Library/Frameworks and use /tmp/newversion as the basis for an installer or something. If you want to install some part, but not all, read the main Makefile. The frameworkinstall is composed of a couple of sub-targets that install the framework itself, the Mac subtree, the applications and the unix tools. There is an extra target frameworkinstallextras that is not part of the normal frameworkinstall which installs the Demo and Tools directories into /Applications/MacPython-2.3, this is useful for binary distributions. If you want to run the Makefile here directly, in stead of through the main Makefile, you will have to pass various variable-assignments. Read the beginning of the Makefile for details. 5. What do all these programs do? --------------------------------- PythonIDE.app is an integrated development environment for Python: editor, debugger, etc. PythonLauncher.app is a helper application that will handle things when you double-click a .py, .pyc or .pyw file. For the first two it creates a Terminal window and runs the scripts with the normal command-line Python. For the latter it runs the script in the Python.app interpreter so the script can do GUI-things. Keep the "alt" key depressed while dragging or double-clicking a script to set runtime options. These options can be set once and for all through PythonLauncher's preferences dialog. BuildApplet.app creates an applet from a Python script. Drop the script on it and out comes a full-featured MacOS application. There is much more to this, to be supplied later. Some useful (but outdated) info can be found in Mac/Demo. The commandline scripts /usr/local/bin/python and pythonw can be used to run non-GUI and GUI python scripts from the command line, respectively. 6. How do I create a binary distribution? ----------------------------------------- First go to Mac/OSX and run "python fixversions.py -a" with the Python you are going to distribute. This will fix the version numbers and copyright strings in the various Info.plist files. Go to the Mac/OSX/Dist directory. There you find a script "build" that does all the work: it configures and builds a framework Python, installs it, creates the installer package file and packs this in a DMG image. All of this is normally done completely isolated in /tmp/_py, so it does not use your normal build directory nor does it install into /. Because the build script locates the Python source tree relative to its own pathname you may have to run it with a full pathname. If you are debugging your install you can pass one argument: the pathname where the build directory is located (i.e. where configure and make will be run), then this directory will be saved between runs of the build script. Do *not* specify your normal build directory here. build will ask you whether you have updated the readme file, and it will offer to include the full documentation in the installer. That option has not been used for a while, and it may not work. If you need to execute code on the client machine after installing Python you can add this to resources/postflight. If you need to do even stranger things you have to read Apple's documentation on PackageMaker and read the source of Mac/scripts/buildpkg.py. 7. Odds and ends. ----------------- The PythonLauncher is actually an Objective C Cocoa app built with Project Builder. It could be a Python program, except for the fact that pyobjc is not a part of the core distribution, and is not completely finished yet as of this writing. Something to take note of is that the ".rsrc" files in the distribution are not actually resource files, they're AppleSingle encoded resource files. The macresource module and the Mac/OSX/Makefile cater for this, and create ".rsrc.df.rsrc" files on the fly that are normal datafork-based resource files. Jack Jansen, Jack.Jansen@cwi.nl, 15-Jul-2004.