Charming Python #17 (20010156)

Review of Python IDEs

David Mertz, Ph.D.
Accidental Ideologue, Gnosis Software, Inc.
March, 2001

David looks at a half-dozen Python integrated development environments, and compares features, platforms, and stability across them. He finds--perhaps as an unintended testament to the open source model--that the free products seem to stack up much better than the commercial ones.

What Is Python?

Python is a freely available, very-high-level, interpreted language developed by Guido van Rossum. It combines a clear syntax with powerful (but optional) object-oriented semantics. Python is available for almost every computer platform you might find yourself working on, and has strong portability between platforms.

The Raw And The Cooked

I have had the opportunity in the last couple weeks to take a fresh look--or a first look--at a number of Python development environments. While it will probably take a lot to sway me from a tried-and-true "favorite text editor, plus command-line" approach to Python development, interest in more comprehensive integrated development environments (IDEs) for Python is evident on Python discussion sites.

My overall impression of Python IDEs leads me to a somewhat surprising conclusion. Perhaps some general principle underlays this, or perhaps it is merely chance. In general, I find the free tools quite a bit better than the commercial ones that cost money.

Before I begin some reviews of actual IDEs, I should note a couple tools I did not have an opportunity to look at, but that readers might want to check out. In my defense, there is probably quite enough covered in this summary for readers (and myself) to digest at once.

PythonWorks Pro 1.1, from PythonWare looks promising. It includes a Tkinter form designer, a modern editor, a debugger, and sleek looking screenshots. It is available for Linux, Windows, and Solaris. PythonWorks Pro is also a fairly pricely $400 product. Unfortunately, I did not obtain a review copy of the final version in time for review.

Boa Constructor is a rather impressive looking open source Python IDE, that includes a form designer for wxWindows. It also appears to have a decent editor, debugger, project manager, and some other components. Boa Constructor runs on Win32 and X11 (with wxWindows for the appropriate platform required). Unfortunately, its home page bills its development status as "pre-alpha"; as pretty as the screenshots are, I felt it would be hard to recommend something in such an apparently early stage of development.

Of course, the final class of tools not reviewed here are the dozens of excellent text editors out there that include varying Python-friendly features, such as syntax highlighting, execution windows, code-folding, macros, and many other features that even the best IDEs lack. This is not the place to try to cover those, but there is a lot to be said for your favorite, and familiar, text editor.

Drawing A Baseline

There are a number of more-or-less standard free tools available for developing Python code. In general, these tools are stable, consistent, and well-established. On the other hand, the standard free tools are not necessarily all that flashy.

Idle is a fairly basic IDE written in pure Python, using Tkinter. Idle is part of all the standard Python distributions, and is even written by Guido van Rossum himself (at least originally, and in large part). You should be able to run Idle anywhere you can run Python and TK. Idle starts out as an enhanced interactive shell window (with a bit better cut-and-paste, scrollback, etc. than the basic interactive prompt). Add to that a Python-aware editor (no code-folding, but nice syntax highlighting and code-completion), class-browser, and debugger. The menus are TK "tear-off" style; that is, clicking on the dashed line at the top of any pull-down menu will promote that menu to its own persistent window. The "Edit" menu in particular is nice if kept "docked" at the side of your desktop. Idle's debugger provides, breakpoints, stepping and variable watches; but nothing so fancy as poking at memory locations and variable contents, or performing timings and other analyses. Of course, usually my own debugging style is some scattered print statements, but your mileage may vary.

A few glitches jump out in Idle--at least as of 0.6. At least on my Win95r2 machine (where I have been playing with it), pop-up templates have an annoying habit of staying on screen and blocking what you are trying to type. Probably more important is that it is really easy to freeze up Idle by running an errant script. For example, the code while 1: x=1 winds up requiring a forced-close of Idle itself, not just of that script's execution. Obviously, one prefers not to write such code in the first place, but even the plain-old Python interactive session lets you kill it with a Ctrl-C (and the session with it, admittedly).

PythonWin is, in most respects, a few steps better than Idle. Of course, as the name suggests, this tool is only for Win32 users. The easiest way to get PythonWin is probably to download the ActivePython 2.0 distribution, which is quite slick in itself (I installed build 203 for this column). ActiveState's Python includes a good collection of extra modules, with some selectable as extra downloads during the installation, such as NumPy and PIL. In particular, one extra is PythonWin (Idle is also there), and the useful PythonCOM extensions for Windows scripting. ActiveState makes non-Windows distributions also, but some components will not be relevant outside windows.

PythonWin is extremely comfortable to work with (as much as one can be comfortable on Windows). It has a nice editor, with code-folding, syntax highligting, and code-completion. PythonWin does not include any sort of form designer, as some IDEs do; but it has an excellent debugger with watches, code inspection, an interactive debug window, breakpoints, and everything you would expect in a debugger. For the most part, PythonWin is stable, although once in a while some erratic freezeups have occurred while working with it on a Win95r2 machine. In appearance, PythonWin is fairly simple, but attractive, and makes nice use of paned and dockable elements (which I somewhat prefer to the Idle style of "many windows everywhere" which is shared by some other IDEs). PythonWin also integrates with ActiveState's HtmlHelp version of Python documentation, and with PythonCOM.

MacPython IDE is similar to PythonWin, modulo the platform difference. Like Idle and PythonWin, MacPython IDE comes with its platform's standard distribution, and is free software (written by Just van Rossum). The first thing I recommend doing after installing MacPython is grabbing the Advanced Editor Patch (see Resources). Applying the patch was flakey in my attempt, but worked on the third try (I don't quite know what the problem was at first); with the patch you get syntax highlighting and some context-sensitive function/module help functions. Besides being standard, MacPython IDE is the only IDE I know of for working with Python on the Mac. Fortunately, Just van Rossum has created something that is both very Pythonic and very Mac-like.

With MacPython IDE you get a Python command window (which is more of a step for Macs, which have no command-line of their own), an editor, a debugger, and even a profiler. Within the environment, you also have a function jump list, a module browser, and a few miscellaneous tools. The debugger is good, but has no watches. The editor is a bit crude "out of the box", but the patch mentioned adds syntax highlighting; but there is still no code-folding or code-completion (you do get contextual function docstrings with the patch). Building in a profiler is something most of the IDEs do not include, so MacPython stands out here.

A Few Seconds Of Longitude

Under the "free but not standard" category, I had a chance to look at Komodo. Komodo seems to have a fair amount of "buzz" around it, but it is still in beta, so it is not certain how it will pan out. Komodo is a mutli-language, multi-platform IDE from ActiveState. In an interesting decision--that may or may not amount to much--Komodo is based on the Mozilla framework. At first brush, it would seem that a web-browser would not necessarily have that much code that is useful for an IDE, but ActiveState seems to have put it to good use (Mozilla is trying to be a "platform" rather than just a browser, it is true).

The Beta 1.3 I looked at supports development of Python, Perl, TCL, Javascript, and XML, with syntax highlighting of another dozen languages thrown in (but not much more language-wise yet). The Python support is currently the strongest. There is a beta available currently for Win32 and Linux, but other platforms might follow.

The best way to think of Komodo, in my opinion, is as a superset of PythonWin. It does not share most of the same codebase, as far as I know, but it has a very similar feel to work with. Because of the Mozilla heritage, Komodo is the slickest looking product in my roundup; but for the same reason it is also the slowest. I would not recommend trying Komodo on an older machine--it is usable on the 366Mhz Win95r2 machine I tested it on, but not speedy. The debugger and editor look and feel similar to PythonWin; but you can edit a lot of extra languages, and debug Perl, as well as Python. Plus you can run Komodo on Linux. One quite clever and unique Komodo feature is a "code check" feature that works like spell checkers in recent wordprocessors: problem code is marked with a squiggly underline as you type; you can keep typing, but it is a good reminder to go back to fix the problem before you are done. Komodo does not attempt to build in any sort of form designer or graphical programming, but other than that it seems quite well-rounded for a beta.

Crossing The Date Line

Now let us look at ways to spend money on Python IDEs. One imagines that commercial products would offer something extra to merit their money cost. In some respects they do; but unfortunately, I found neither the $100 WingIDE nor the $80 BlackAdder (but $400 for redistribution of components) sufficiently stable to recommend using them for live development. Nominal feautures are not worth much if you cannot practically use the IDE. Hopefully, both products will improve with versions and patches.

BlackAdder is a QT-based development environment for Linux and Windows. Of the products covered in this column, it is the only one with a form designer, and its form designer is itself quite nicely done (for PyQT programming). Like Delphi, Visual Basic, and similar tools, you can place widgets on palettes, and play with their attributes and behaviors in a "properties" sheet The icons for elements have a somewhat blockish look, especially when grayed out, but the aesthetic issue is minor. The source editor provides code-folding and syntax highlighting, but not code-completion tips. BlackAdder has a decent debugger, on par with the free tools except for the lack of watches.

Unfortunately, in testing V1.0 Beta 2, I encountered some serious usability problems. I tested the Mandrake, Slackware and Windows packages (but not Debian or Redhat, although I think the Linux variants are only packaging differences). Various problems occurred everywhere (perhaps in part because of reliance on exact OS versions and revisions). For example, the default font was far too small to read on both Linux and Windows. Changing the editor font required a quite tedious process of individually changing the font for each of 20 syntax markup elements (no "inherit font" option, as many text editors and IDEs have). Worse than this, under both Mandrake 7.1 and a customized Slackware 7.1, the Python interpreter "terminates unexpectedly" when BlackAdder launches. You can edit files, but not run them in the IDE. My attempts to change Python paths--and point to either Python 2.0 or Python 1.5.2 managed to change the error message, but not fix things. Further, under Windows I found that some Python scripts would not open under BlackAdder; I would get an "X is not a valid BlackAdder file" instead. There was no obvious pattern to this message. These are the sorts of matters that one might be able to resolve with some work--but if you've just shelled out $400, you are usually not in a mood for debugging the product you purchased.

WingIDE has the making of a quite nice IDE. Its editor includes syntax highlighting for a large number of languages, although beyond that it is Python-oriented. The source code browser is wonderfully useful for browsing projects/modules (presenting either navigable source, or docstring summaries). The debugger is well arranged, although without watches. The editor has nice command-completion and a function jump list, but no code-folding. The project-oriented style of the IDE would be useful for large products (better in this regard than most of the free IDEs, except Komodo). The overall interface is somewhat similar to an enhanced Idle in using the "many windows" arrangement familiar in many TK and XWindow interfaces. I prefer some use of docking and panes (but not the excesses of MS Visual Studio, in this regard), but different developers will like different styles of windowing. WingIDE has a lot of promise as a development environment.

Like BlackAdder, however, WingIDE--in both the 1.0 and 1.1b3 versions I tested--has problems that make it difficult to recommend for serious development. There are some small annoyances, like the annoying license key configuration procedure, and the erratic--but mostly missing--tooltips for toolbars. Also, little warts exist like the absence of an "open recent" menu item, and the fact you can only open an interactive shell window when a program is running (not just to experiment with code). But those types of things are minor. The killer is WingIDE's habit of randomly generating segmentation faults on my Mandrake 7.1 box. Everything dies in these cases, and you lose anything you were working on. "Save often" may be good advice, but is not really enough to make WingIDE usable fulltime.


Information on PythonWorks Pro 1.1, from PythonWare can be found at:

The wxWindows/wxPython-based screen builder and development environment, Boa Constructor, can be found at:

ActiveState's ActivePython 2.0 (for Win32) includes Mark Hammond's PythonWin IDE, as well as a number of other goodies (they also have Linux and Solaris versions).

ActiveState's Komodo multi-language IDE is currently available for Win32 and Linux:

A good starting point for MacPython information is:

The Advanced Editor Patch, and other enhancements to the MacPython IDE can be found at:

The Kompany's BlackAdder homesite is at:

Read Archaeopteryx' official WingIDE information at:

About The Author

Picture of Author David Mertz is blessed with the virtues of laziness, and impatience, and in his wisdom wishes to warn the world that hubris should not be confused with chutzpah or machismo. David may be reached at; his life pored over at Suggestions and recommendations on this, past, or future, columns are welcomed.