JetBrains PyCharm Blog

Giacomo Lacava recently wrote a blog post describing his not very good experience with Jython support in PyCharm. I’d like to explain what the situation actually is.

First of all, PyCharm currently supports Python versions starting with 2.4. This means that PyCharm’s own components written in Python use language features of Python 2.3 and 2.4, and simply will not run with Jython 2.2. With Jython 2.5, things like loading the list of library paths and completion for the standard library (which Giacomo had problems with) should work with no problems.

Second, it’s true that we do not support parsing jar files in PyCharm. When PyCharm was initially designed, the Java support in IntelliJ IDEA was a monolithic component, and we had the choice of either including it all or leaving it all out. Including it would mean that we would have a Python IDE that could do, say, an “Introduce Parameter” refactoring for Java but not for Python. Which would be really, really weird. So we decided to leave it all out.

On the other hand, the IntelliJ IDEA Python plugin can rely on the Java support in IntelliJ IDEA itself, and it contains all the necessary logic to support Java/Python interop. The plugin can resolve imports from Python files to Java code, perform cross-language refactorings, auto-import Java classes in Python code, etc. And as far as we know, it provides a better Jython development experience than any other IDE.

The good news is that, since that time, our Java support has become more modular, and now we have the option to include just enough of it in PyCharm to support Java/Python interop but not anything more. Therefore it’s possible that a future version of PyCharm will have the same degree of Jython support as the IntelliJ IDEA Python plugin currently has. However, we’re still not sure if there’s enough of a target audience for this functionality. So if you’d like to have this, please let us know.

The final release of PyCharm 2.0 is right around the corner, and now we’re giving you the last chance to test the new version before the final release and report any problems that you run into. Among the fixes and improvements that went into the new release, I would like to highlight the following:

• “Open in Browser” (Alt-F2) now works for Django templates. PyCharm tries to figure out the URL of the view in your application that renders this particular template, and to open that URL. If it fails, it simply opens the template as a static HTML file.
• The Move Statement action (Ctrl-Shift-Up/Down) has been rewritten and is much more reliable now.
• The Google App Engine integration now supports the Python 2.7 runtime added in Google App Engine 1.6.0.

The new version is available for download from the EAP page. As always, please submit your feedback to the issue tracker.

This week’s EAP build of PyCharm 2.0 is probably going to be the last one before the Beta release, and as such, it brings the last major batch of new features to be included in PyCharm 2.0:

• When opening a project, you now have an option to add it to the projects already open in the current window;



• The JavaScript debugger is now included in the PyCharm distribution and integrated with the Django server run configuration;



• The Python and Django consoles now support customization, including the possibility to specify a script which is automatically executed when the console is opened;

You can download the new build and check out the full release notes on the EAP page.

And now that the build is out, I can finally go home and get back to my game of Skyrim.

Cython is a language that allows you to write C extensions for the Python language using the familiar Python syntax. You can use Cython for creating extensions that can be 50-100 times faster than pure-Python modules. Also Cython allows you to integrate your Python code with C libraries more smoothly than the standard ctypes library or generated C bindings.

We are currently working on Cython support in PyCharm. Here is an overview of what’s already available in the EAP builds.

First of all, you get Cython syntax highlighting and error checking:

Next, there is context-sensitive code completion for Cython keywords, fields of structs, and attributes of extension types:

We will continue working on code completion for other elements, such as type names.

You can go to definitions and find usages of Cython cdef variables, functions, structs, and extension types. This is especially useful if you take into account various ways of importing Cython files, such as include statements and implicit imports of Cython definition files:

We have also adapted some Python inspections and refactorings for Cython. For example, PyCharm will highlight unresolved references in your Cython code:

There are various ways of compiling Cython modules: setup.py with Cython functions for distutils, Makefiles that directly call the cython compiler, etc. In PyCharm you can set up any external tool for compiling your Cython code from the IDE:

You can also set up the go to error line functionality via output filters for external tools:

Cython support in PyCharm is still work in progress. More Cython-related features and improvements will be available in PyCharm 2.0 EAP builds in the coming weeks.