Living Code

I’m still here. I’m going to post the previous examples .dmg with some corrections pointed out by Bob Ippolito (4-space indents, don’t modify data directly in the Bundle). I’ve been quiet because a) I’ve been hitting some walls with Renaissance and investigating work-arounds and alternatives, and b) my coding/blogging time is pretty much between the time I get the kids to bed and the time my wife comes home from tutoring.

I’m investigating the PyGUI and Wax APIs, to see if they are worth porting to run on top of Cocoa (PyGUI runs on Carbon, Wax runs on top of wxPython). Both are attempts to make GUI creation more “Pythonic,” which is a Good Thing™. I have figured out how to get the menus initialized using pure Python (on top of PyObjC, of course), or maybe the newer pyobjc/py2app has fixed the problem, but it is possible to build applications in Python with no Nib file (or Renaissance .gsmarkup file) at all. My earlier inabillity to do that is what drove me to Renaissance in the first place.

I’ve also discovered the nibtool utility, which I did not know about. This allows you to see a textual representation of the nibs created by Interface Builder, search and replace strings (class names, etc.). This is a major discovery. Now if you could take the textual representation and put it back… I’m going to have to investigate this further.

In other news, I will be giving a presentation on Tuesday, February 1 at the Vancouver Zope and Python Users Group (VanPyZ) at 7:00 p.m. It will be a variation on the talk I gave in December to the XML users group, updated with what I’ve been exploring since then. Specifically I will show a simple (Hello World) application built three different ways, with Renaissance, with Interface Builder, and in pure Python. I’ll also show some apps written in other toolkits (wxPython, tkinter) for comparison. I hope some of my readers are close enough to make it.

I’ll also be attending the Northern Voice blogging conference here in Vancouver on Saturday, February 19th. I’m looking forward to meeting some fellow bloggers face to face, rather than RSS to RSS.

Finally, I managed to install Python 2.4 today, and so far nothing has been obviously screwed up, so I’ll be exploring some of the crunchy new features here in the near future.

More posts coming soon. Honest!

My talk at VanX last night was a success. Not many people showed (too close to Xmas), but the ones who did seemed to enjoy my presentation on Cocoa, Python, and Renaissance. Gerald was a great host, SchemaSoft provided a good (and convenient!) venue, Paul came to show support, and BlastRadius (my employer) sponsored the snacks. After we went to Mira in Yaletown for beers and tech talk, had the whole place to ourselves, and a musician playing Flamenco guitar, then I walked across the bridge to home. A great end to a great evening.

I’ve posted my slides at livingcode.org/slides/renaissance.html using Eric Meyer’s neat S5 tool to put the whole slideshow into one HTML file.

I’ve also built a new .dmg containing all the source code and built, runnable examples (seven of them now), although they’re not all fully functional yet. More example gsmarkup to view, improved setup scripts, and they all have icons now. The file is examples 2004-12-17 on SourceForge.

I’ve been working hard to put this all together, which hasn’t left much time for posting, but I will have a lot more to say real soon now.

Today’s Example is a simple, but full application. Our setup file is getting more complicated as we give the app a custom icon and a name which isn’t taken from the main python file. We’re finally using the menus for more than just default behaviors. We’re loading in resources at runtime. We’re adding a custom About box. And we’re taking advantage of Python standard libraries from within a Cocoa program. One icon file + 224 lines of python, XML, and HTML.

Some years ago Brian Eno and Peter Schmidt created a deck of cards for brainstorming your way through artistic blocks. Each card had one idea, and they were called Oblique Strategies. The Whole Earth Review published a list of some of the strategies, the decks went through several editions, and there were quite a number of programs written to simulate drawing a card from the deck. The Oblique Strategies Web Site has more details. You can buy the deck from Brian Eno’s site. And a group called curvedspace created a nice OS X version which you can download for free from their site.

The curvedspace app is so nice, in fact, that we’re going to slavishly imitate it. There are only a couple of problems with it. First, you can’t add your own quotes and sayings to the mix. Second, it’s free, but not open source, so you can’t patch it to allow you to add your own quotes. Tonight’s example will build a version identical to the curvedspace tool, but which allows you to choose from among several quote files, not just the Oblique Strategies. A future exercise will be to allow the user to customize it with new quotes from within the running application.

Since there’s quite a bit more code, and by reader request, this example is contained on a downloadable .dmg file. The file contains both the finished, runnable application, and all the source code. I’ll just be describing highlights of what’s different from earlier examples. You can download it all here.

What’s new? First of all, the setup.py defines a plist resource inline to map some of the application features. This gives the application a name (”Oblique Strategies” rather than picking up “oblique” from the python file, and sets up some info for the About box. The setup call is a little more complex too, including English.lproj (which holds our icon) and Credits.html (which is the content of our About box), and passing in the plist we defined.

In the MainMenu.gsmarkup we have added a bunch of menu items to the File menu, to allow the user to pick a quotation file. What’s interesting is that we’ve implemented ‘About Oblique Strategies’ and Edit->Copy, but those menu items didn’t have to change.

In oblique.py, the main script, we implement a subclass of NSWindow called TexturedWindow. This is to work around a limitation of the current version of Renaissance, which doesn’t support so-called Metal windows (because GNUstep doesn’t have them). Nicola has fixed this in CVS, so it will be in the next release, but in the meantime it is a simple class (4 lines of code) and we use the instanceOf attribute of <window /> to call our subclass in the MainWindow.gsmarkup.

Our AppDelegate is similar to earlier examples, but has grown a couple of methods. The change() method is called by our one button to select another quotation at random from the selected file (or a random file if you like). The chooseFile_() method checks to see which menu item called it, and based on the menu item, selects the file for future calls to change(). There is one support function, getQuote(filename) which uses Python standard file manipulation and the random module to pick a quote (much less verbose than doing this from Objective-C).

All that’s left are the quote files. These are simple text files with short quotations, one to a line. If a quote requires newlines, they can be embedded with ‘\n‘. The included files have quotes from Martin Fowler’s book “Refactoring,” the book “The Pragmatic Programmer,” the Magic 8-Ball, Jenny Holzer’s Truisms, and more. Enjoy!

I’ve been requested to make binary packages of the applications for people who haven’t been following along at home. The first application I’ve made available is the GMarkup Browser, so you’ll need some GMarkup files to browse with it, either from the example here, the Renaissance site (the source package has lots of examples in the Examples folder) or by writing your own (the whole point is that that it isn’t hard to do). It’s available from the Living Code project on SourceForge.

I’ll make others available as I get the chance, now that I’ve figured out the SourceForge release system (sort of) and the steps for making a disk image for distribution. Soon I need to figure the Mac Package Manager and Installer (which py2app supports) so folks who want to install several apps don’t end up with multiple copies of Renaissance too. Baby steps for now, there’s a lot to learn.

Mac OS 10.3 only. Feedback appreciated. Coming soon: applications that I can post meaningful screenshots of.

Various small improvements. Switched the template so code doesn’t run off the edge so easily. Fixed whitespace, which I forgot to do after switching the template (thanks, Xavier, for pointing that out!). All the code for the renaissance examples is available via cvs from the SourceForge Living Code project, in the somewhat predictable cvs module, renaissance_examples. As some of the examples grow, I may only publish the highlights in the blog, and put the remainder in CVS. We’ll se how it goes.

Coming attractions. I’m researching how to build the Renaissance projects so they can be distributed (I haven’t forgotten you, Jorjun, I’m just still figuring it out myself). I can do it now (thanks, Bob!), but I want something more straightforward to build. Hopefully later tonight.

Now that we’ve got a brower for Renaissance files (see previous post), I wanted to create a markup file to show off most of the widgets and options, but realized there is no markup for tabbed views, so I’m going to try creating new tags from Python, and show how to do that. When I’ve got the tags which represent Cocoa widgets that do not yet have Renaissance representations working, then I’ll put together the demo gsmarkup file.

Then back to the Small Nerd examples and a couple of other applications (ports of existing tools, nothing terribly original yet).

It’s been nice to hear from people who are enjoying this series. If there are specific things you’d like to see, let me know, either in the comments, or at dethe(at)livingcode.org